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  #1  
Old March 9th, 2012, 8:18 AM
shaolin95 shaolin95 is offline
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Please help with VTF-15h and Room placement.

Hello!
So I have a VTF-15H and MFW15 on one corner of the room which is sort of midway.
I noticed while measuring where I sit that the 20Hz test registers about 73db. If I move closer to the front wall it keeps going lower and it I move to the back wall..it goes lower for a few feet then it goes up like to 90 or even more. A HUGE difference there.

I am wondering what can I do to move that to my sitting location
I do have several GIK acoustic panels which are fantastic and highly recommended, but that have been shamelessly placed at random.
I guess it would be easier to show some pictures of what I have and how the room looks so you guys can offer some advice so I will get some pics tonight.
Here is a rough sketch though.
Its an unfinished basement where there are no ceiling panels. All walls are concrete except the left one which is gypsum board.
Ceiling is about 8'4" tall.

Thanks.


PS performance feels awesome where I sit but I just cant imagine how much better it could be if I had all that extra power where I sit
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Last edited by shaolin95 : March 9th, 2012 at 11:18 AM.
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  #2  
Old March 9th, 2012, 10:23 AM
Dr_Hsu Dr_Hsu is offline
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Originally Posted by shaolin95 View Post
Hello!
So I have a VTF-15H and MFW15 on one corner of the room which is sort of midway.
I noticed while measuring where I sit that the 20Hz test registers about 73db. If I move closer to the front wall it keeps going lower and it I move to the back wall..it goes lower for a few feet then it goes up like to 90 or even more. A HUGE difference there.

I am wondering what can I do to move that to my sitting location
I do have several GIK acoustic panels that have been shamelessly placed at random.
I guess it would be easier to show some pictures of what I have and how the room looks so you guys can offer some advice so I will get some pics tonight.
Here is a rough sketch though.
Its an unfinished basement where there are no ceiling panels. All walls are concrete except the left one which is gypsum board.
Ceiling is about 8'4" tall.

Thanks.


PS performance feels awesome where I sit but I just cant imagine how much better it could be if I had all that extra power where I sit
You have discovered the physics of sound waves - middle of the room - weak deep bass. You see, the middle is where the null for the deep bass is. Any chance of having the screen in the middle and sit at one end of the room?
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  #3  
Old March 9th, 2012, 10:44 AM
shaolin95 shaolin95 is offline
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Originally Posted by Dr_Hsu View Post
You have discovered the physics of sound waves - middle of the room - weak deep bass. You see, the middle is where the null for the deep bass is. Any chance of having the screen in the middle and sit at one end of the room?
That will be an interesting concept and a damn good one
So my idea of placing the subs in that almost midway corner was due to being close to a good viewing distance and also to use the walls to increase output. Like I said..the impact is big but of course thanks to the SPL meter now I know I am missing even more
You dont think any amount of room treatment can fix that do you?

Last edited by shaolin95 : March 9th, 2012 at 11:16 AM.
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  #4  
Old March 9th, 2012, 11:24 AM
Dr_Hsu Dr_Hsu is offline
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Originally Posted by shaolin95 View Post
That will be an interesting concept and a damn good one
So my idea of placing the subs in that almost midway corner was due to being close to a good viewing distance and also to use the walls to increase output. Like I said..the impact is big but of course thanks to the SPL meter now I know I am missing even more
You dont think any amount of room treatment can fix that do you?
Placing the sub close to you certainly helped a lot for the mid and upper bass - very high SPL at those frequencies. You should have a very strong 30 Hz where you sit. 30 Hz will be strong at the ends and in the middle. Since most program material do not go much below 30 Hz, you can also be happy with your current setup.

Is the basement your 'man cave'? If so, what I suggested should give you the crazy bass you want. Have your sofa two feet out from the back wall. Place the two subs directly behind your sofa. Have the TV (or projection screen) in the middle. One advantage of doing that is, if you use the system for music as well, the front speakers are pulled out into the room a lot, giving you much better soundstage depth (no early reflections off the wall behind the front speakers).

No. Unfortunately no amount of treatment can change that.
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  #5  
Old March 9th, 2012, 11:50 AM
shaolin95 shaolin95 is offline
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Originally Posted by Dr_Hsu View Post
Placing the sub close to you certainly helped a lot for the mid and upper bass - very high SPL at those frequencies. You should have a very strong 30 Hz where you sit. 30 Hz will be strong at the ends and in the middle. Since most program material do not go much below 30 Hz, you can also be happy with your current setup.

Is the basement your 'man cave'? If so, what I suggested should give you the crazy bass you want. Have your sofa two feet out from the back wall. Place the two subs directly behind your sofa. Have the TV (or projection screen) in the middle. One advantage of doing that is, if you use the system for music as well, the front speakers are pulled out into the room a lot, giving you much better soundstage depth (no early reflections off the wall behind the front speakers).

No. Unfortunately no amount of treatment can change that.
This the whole house is my cave And if I get married again...it will still be mine...I do not allow anyone to mess with my space.
Anyways...now you got me thinking.
Yes the impact is great where I am sitting specially since I play loud for sure...so I need to think if its worth moving back since the room is not very wide and on that part is even less (11-6")

I guess I will try moving them back there then sit there and see if the feeling is enough to make me change all that.
The screen is a blackout cloth a bit over 12' wide so you can see it will be hard
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  #6  
Old March 9th, 2012, 12:44 PM
Dr_Hsu Dr_Hsu is offline
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Originally Posted by shaolin95 View Post
This the whole house is my cave And if I get married again...it will still be mine...I do not allow anyone to mess with my space.
Anyways...now you got me thinking.
Yes the impact is great where I am sitting specially since I play loud for sure...so I need to think if its worth moving back since the room is not very wide and on that part is even less (11-6")

I guess I will try moving them back there then sit there and see if the feeling is enough to make me change all that.
The screen is a blackout cloth a bit over 12' wide so you can see it will be hard
Lucky guy! No WAF to worry about???

If it sounds much better back there (I would sit in the wider section of the basement), I would simply get a pull down screen that you retract when not watching so you can access the other half of the basement.
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  #7  
Old March 9th, 2012, 12:56 PM
shaolin95 shaolin95 is offline
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Originally Posted by Dr_Hsu View Post
Lucky guy! No WAF to worry about???

If it sounds much better back there (I would sit in the wider section of the basement), I would simply get a pull down screen that you retract when not watching so you can access the other half of the basement.
hahaha indeed. Even with my ex we had an arrangement , my area is my area.

Ok I guess I will look into pull down screens prices for such a size or maybe some huge stand for a screen but it would be super heavy I dont really need to move it since the room is for just HT so I will look for an option to leave it static there.
Thanks though...that sub is just a monster!
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  #8  
Old March 9th, 2012, 1:34 PM
Dr_Hsu Dr_Hsu is offline
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Originally Posted by shaolin95 View Post
hahaha indeed. Even with my ex we had an arrangement , my area is my area.

Ok I guess I will look into pull down screens prices for such a size or maybe some huge stand for a screen but it would be super heavy I dont really need to move it since the room is for just HT so I will look for an option to leave it static there.
Thanks though...that sub is just a monster!
If you sit at one end of that basement, the room mode is at 15 Hz. So you get plenty of room gain at 15 Hz. You can set the 15H to 2 ports open, EQ2, Q =0.3 and still get strong extension down to 15 Hz!
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  #9  
Old March 9th, 2012, 1:55 PM
shaolin95 shaolin95 is offline
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Originally Posted by Dr_Hsu View Post
If you sit at one end of that basement, the room mode is at 15 Hz. So you get plenty of room gain at 15 Hz. You can set the 15H to 2 ports open, EQ2, Q =0.3 and still get strong extension down to 15 Hz!
hahaha you are killing me! Is a good thing the weekend is here...a LOT of testing for me now...but why didnt you add wheels to that thing?

I already contacted someone about some screens just in case

One thing, you said .3 So to understand that well .3 will give more output and .7 more extension, correct?
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  #10  
Old March 9th, 2012, 4:43 PM
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[quote=shaolin95;132911]hahaha you are killing me! Is a good thing the weekend is here...a LOT of testing for me now...but why didnt you add wheels to that thing?

I already contacted someone about some screens just in case

One thing, you said .3 So to understand that well .3 will give more output and .7 more extension, correct?[/

Low Q means tighter bass with a gentle roll off in the low bass. Since your room should have a lot of low bass boost, the early gentle roll off from using Q of 0.3 should give the best result. It would also raise the headroom some.
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  #11  
Old March 9th, 2012, 5:18 PM
shaolin95 shaolin95 is offline
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[quote=Dr_Hsu;132912]
Quote:
Originally Posted by shaolin95 View Post
hahaha you are killing me! Is a good thing the weekend is here...a LOT of testing for me now...but why didnt you add wheels to that thing?

I already contacted someone about some screens just in case

One thing, you said .3 So to understand that well .3 will give more output and .7 more extension, correct?[/

Low Q means tighter bass with a gentle roll off in the low bass. Since your room should have a lot of low bass boost, the early gentle roll off from using Q of 0.3 should give the best result. It would also raise the headroom some.
Thanks again...you truly support your products!
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  #12  
Old March 9th, 2012, 6:10 PM
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[quote=shaolin95;132913]
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Originally Posted by Dr_Hsu View Post
Thanks again...you truly support your products!
Thank you! Please help spread the word ...
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  #13  
Old March 10th, 2012, 11:40 AM
shaolin95 shaolin95 is offline
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[quote=Dr_Hsu;132914]
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Originally Posted by shaolin95 View Post

Thank you! Please help spread the word ...
Oh trust me, I am! I will be doing a review as well soon. I used to work with AV123 but before that I used to get samples from different ID companies to review speakers so I am going back to that now as a hobby.
I noticed that moving forward out of the worst area (40-60% lenght) I am actually getting higher 16 and 12hz output than 20Hz...well technically it may not be right as I forgot to correct the readings so I will work on that today.
Also, for 16Hz..if I open the room door I get almost 3 extra dbs! Gotta love acoustics
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  #14  
Old March 10th, 2012, 12:09 PM
Dr_Hsu Dr_Hsu is offline
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[quote=shaolin95;132918]
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Originally Posted by Dr_Hsu View Post
Oh trust me, I am! I will be doing a review as well soon. I used to work with AV123 but before that I used to get samples from different ID companies to review speakers so I am going back to that now as a hobby.
I noticed that moving forward out of the worst area (40-60% lenght) I am actually getting higher 16 and 12hz output than 20Hz...well technically it may not be right as I forgot to correct the readings so I will work on that today.
Also, for 16Hz..if I open the room door I get almost 3 extra dbs! Gotta love acoustics
That is what I expect - if you see my post above, I said your room mode is at 15 Hz, with 12 and 16 Hz bands closest to that frequency.
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  #15  
Old March 10th, 2012, 8:15 PM
shaolin95 shaolin95 is offline
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[quote=Dr_Hsu;132919]
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Originally Posted by shaolin95 View Post

That is what I expect - if you see my post above, I said your room mode is at 15 Hz, with 12 and 16 Hz bands closest to that frequency.
Indeed you got that right. I am even getting nice 10Hz output
A shame the CD that came with the sub only has down to 16Hz. I was going to use Tone Generator but not sure what type of sound to select. It comes with Triangle as default I think.

In any case, when I add the MFW15 to the mix the 20 freq with an adjust listening position gets closer to the 16Hz performance so except for peaks at 25 and 31.5 all freq up to 100 are pretty flat.
I am for sure leaving the door open for that extra 4dbs of 16Hz performance
A test of War of the Worlds with the adjustments was awesome! I can feel the pressure , pants flapping and chair vibrations...so addictive.
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Old March 10th, 2012, 8:41 PM
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[quote=shaolin95;132925]
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Originally Posted by Dr_Hsu View Post
Indeed you got that right. I am even getting nice 10Hz output
A shame the CD that came with the sub only has down to 16Hz. I was going to use Tone Generator but not sure what type of sound to select. It comes with Triangle as default I think.

In any case, when I add the MFW15 to the mix the 20 freq with an adjust listening position gets closer to the 16Hz performance so except for peaks at 25 and 31.5 all freq up to 100 are pretty flat.
I am for sure leaving the door open for that extra 4dbs of 16Hz performance
A test of War of the Worlds with the adjustments was awesome! I can feel the pressure , pants flapping and chair vibrations...so addictive.
Excellent! Definitely leave that door open!
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  #17  
Old March 11th, 2012, 3:06 AM
Nigel_Pl Nigel_Pl is offline
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Originally Posted by shaolin95
Indeed you got that right. I am even getting nice 10Hz output
Hi Shaolin95,

I am curious, what do you mean by nice 10Hz output? High SPL? Something shaking in the room?

Regards,
Nigel
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Old March 11th, 2012, 8:01 PM
shaolin95 shaolin95 is offline
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Hi Shaolin95,

I am curious, what do you mean by nice 10Hz output? High SPL? Something shaking in the room?

Regards,
Nigel
Hello!
In my room I get usable bass down to 10Hz. My 16Hz gives my a bit higher SPL than 20Hz as well due to my room acoustics and the experience is amazing. Feeling the bass is just something everyone should experience.
Going to the movies now is out of the question!

I followed the recommendations on the manual to calibrate it and noticed that based on the steps there I am running 6db hot my subwoofer (duals) but in real life, at -7 on my receiver I am getting max 110db in Cloverfield for example and the bass just feels perfect while the action from the speakers is great and clear without getting too loud to bother my ears.
Most movies I play at -5 so I think that I will leave it the way it is for now.
Still more testing to do when I get help to move them around...is the hard part of having concrete floor...sliding around is not an option
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Old March 11th, 2012, 9:39 PM
Dr_Hsu Dr_Hsu is offline
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Originally Posted by shaolin95 View Post
Hello!
In my room I get usable bass down to 10Hz. My 16Hz gives my a bit higher SPL than 20Hz as well due to my room acoustics and the experience is amazing. Feeling the bass is just something everyone should experience.
Going to the movies now is out of the question!

I followed the recommendations on the manual to calibrate it and noticed that based on the steps there I am running 6db hot my subwoofer (duals) but in real life, at -7 on my receiver I am getting max 110db in Cloverfield for example and the bass just feels perfect while the action from the speakers is great and clear without getting too loud to bother my ears.
Most movies I play at -5 so I think that I will leave it the way it is for now.
Still more testing to do when I get help to move them around...is the hard part of having concrete floor...sliding around is not an option
Maybe you can try some sliders like these:

http://www.homedepot.com/h_d1/N-5yc1...&storeId=10051
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Old March 12th, 2012, 1:22 AM
Nigel_Pl Nigel_Pl is offline
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Originally Posted by shaolin95 View Post
Hello!
In my room I get usable bass down to 10Hz. My 16Hz gives my a bit higher SPL than 20Hz as well due to my room acoustics and the experience is amazing. Feeling the bass is just something everyone should experience.
Going to the movies now is out of the question!

I followed the recommendations on the manual to calibrate it and noticed that based on the steps there I am running 6db hot my subwoofer (duals) but in real life, at -7 on my receiver I am getting max 110db in Cloverfield for example and the bass just feels perfect while the action from the speakers is great and clear without getting too loud to bother my ears.
Most movies I play at -5 so I think that I will leave it the way it is for now.
Still more testing to do when I get help to move them around...is the hard part of having concrete floor...sliding around is not an option
Hi Shaolin,

Sounds like you have a great setup! I doubt I could get through a loud movie at -5 in my current room, more like -10 maximum, typically -25 to -20. I am hoping to move to a larger place, with more living zones, which will allow me to turn up the volume without bothering the rest of the family.

I've experienced couch shaking and pressure on my insides, but I don't think I've experienced flapping pants. Is that caused by the sound pressure level in general, or a specific range of frequencies? Is that something particular to forward firing and ported subs? I've read, that in one sub shoot out, that the port of a particular sub was producing large gusts of wind like a fan.

Yes, that is one heavy subwoofer. The TN1220 is a lot easier to move in comparison

What instrument are you using to measure as low as 10Hz? Could you hear anything from the sub with a frequency that low?

Regards,
Nige
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Old March 12th, 2012, 8:04 PM
shaolin95 shaolin95 is offline
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Originally Posted by Nigel_Pl View Post
Hi Shaolin,

Sounds like you have a great setup! I doubt I could get through a loud movie at -5 in my current room, more like -10 maximum, typically -25 to -20. I am hoping to move to a larger place, with more living zones, which will allow me to turn up the volume without bothering the rest of the family.

I've experienced couch shaking and pressure on my insides, but I don't think I've experienced flapping pants. Is that caused by the sound pressure level in general, or a specific range of frequencies? Is that something particular to forward firing and ported subs? I've read, that in one sub shoot out, that the port of a particular sub was producing large gusts of wind like a fan.

Yes, that is one heavy subwoofer. The TN1220 is a lot easier to move in comparison

What instrument are you using to measure as low as 10Hz? Could you hear anything from the sub with a frequency that low?

Regards,
Nige
Not sure what causes the flapping thing but I think is more of a pressure thing since I was not in direct path to either sub's ports.
As for 10Hz I think is more of a feel thing although some test tones for some reason do have some sound but does not sound natural as it sounds too high pitched compared to 15Hz etc.
In any case I decided to move them right behind my seat and OMG the experience just went through the roof (and I almost did too! lol).
Seriously the tactile experience, the ultra low frequencies hitting you like that just makes everything a LOT better. Hard to explain but if you have the chance to do it, give it a shot. Mine are NEVER moving from there.
Not only I push them lower but the experience is just on another level..cannot really argue with that.

Last time I tried such a setup I was living in Puerto Rico and it was the sub from my first HT ever..a Kenwood HTB-503..I still remember the model as it was a gift from a very special person. And then my other sub was a Sony W400 (something like that)...of course, the difference is beyond imagination but its fun to think on how one started
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  #22  
Old March 12th, 2012, 8:32 PM
Dr_Hsu Dr_Hsu is offline
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Originally Posted by shaolin95 View Post
Not sure what causes the flapping thing but I think is more of a pressure thing since I was not in direct path to either sub's ports.
As for 10Hz I think is more of a feel thing although some test tones for some reason do have some sound but does not sound natural as it sounds too high pitched compared to 15Hz etc.
In any case I decided to move them right behind my seat and OMG the experience just went through the roof (and I almost did too! lol).
Seriously the tactile experience, the ultra low frequencies hitting you like that just makes everything a LOT better. Hard to explain but if you have the chance to do it, give it a shot. Mine are NEVER moving from there.
Not only I push them lower but the experience is just on another level..cannot really argue with that.

Last time I tried such a setup I was living in Puerto Rico and it was the sub from my first HT ever..a Kenwood HTB-503..I still remember the model as it was a gift from a very special person. And then my other sub was a Sony W400 (something like that)...of course, the difference is beyond imagination but its fun to think on how one started
Cool! I have always advocated a behind the back placement. When the room is not deep like yours, it's better to have the true sub in a front corner and an MBM behind you. In your case, you have a wonderfully deep room and you can place the true sub behind you and not need a MBM!
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Old March 12th, 2012, 8:44 PM
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I am beginning to think the MFW is not needed in this new placement really. I need to test more but then again..nothing like extra power just in case I feel like bringing down the block
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Old March 12th, 2012, 9:44 PM
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I am beginning to think the MFW is not needed in this new placement really. I need to test more but then again..nothing like extra power just in case I feel like bringing down the block
It's good to use both. Of course, it's even better to use two 15H! When you have two subs, each sub is running at a much lower level so their long term reliability is greatly improved.
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Old March 13th, 2012, 10:33 AM
shaolin95 shaolin95 is offline
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It's good to use both. Of course, it's even better to use two 15H! When you have two subs, each sub is running at a much lower level so their long term reliability is greatly improved.
I would love to have 2 or 4 but it will take a while ..besides..not sure how much more I really need now...I am just having too much fun!
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Old March 13th, 2012, 10:47 AM
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I would love to have 2 or 4 but it will take a while ..besides..not sure how much more I really need now...I am just having too much fun!
But but but just think of it - with two, each needs only 1/4 the power to achieve the same output. With four, each only needs 1/16 the power. So much lower distortion, so much more effortless, so much more dynamic, so much more likely to get a heart attack due to too much bass! (Make sure to leave all your things to me in your will)
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Old March 13th, 2012, 2:13 PM
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But but but just think of it - with two, each needs only 1/4 the power to achieve the same output. With four, each only needs 1/16 the power. So much lower distortion, so much more effortless, so much more dynamic, so much more likely to get a heart attack due to too much bass! (Make sure to leave all your things to me in your will)
OMG hahahahaha you are one special doctor! Ok I will for sure! The power..the power!
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  #28  
Old March 13th, 2012, 2:56 PM
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[quote=shaolin95;132925]
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Originally Posted by Dr_Hsu View Post
Indeed you got that right. I am even getting nice 10Hz output
A shame the CD that came with the sub only has down to 16Hz. I was going to use Tone Generator but not sure what type of sound to select. It comes with Triangle as default I think.

In any case, when I add the MFW15 to the mix the 20 freq with an adjust listening position gets closer to the 16Hz performance so except for peaks at 25 and 31.5 all freq up to 100 are pretty flat.
I am for sure leaving the door open for that extra 4dbs of 16Hz performance
A test of War of the Worlds with the adjustments was awesome! I can feel the pressure , pants flapping and chair vibrations...so addictive.
Sorry to disagree with you, with the HPF I doubt very much you're getting much if anything at 10hz. I get nice gain in my room but it drops at 13.5hz or even a tad higher. Since the HPF isn't a wall so it slowly drops off below tune. For useable output I don't see it.

Maybe Dr Hsu can explain it better.


P.S. @Dr Hsu, I went to bed thinking if SMS was engaged for the above graph. I know I said it wasn't but it was gnawing at me and I think it was. I had two peaks, one at 25hz and one at 32hz. Both were reduced by 5db. I'm getting old and my notes aren't as complete as they should be (age thingy). Sorry for the misinformation.

Here is a graph to show what I mean.
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Last edited by Sputter : March 13th, 2012 at 3:07 PM. Reason: added the P.S.
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  #29  
Old March 13th, 2012, 3:22 PM
Nigel_Pl Nigel_Pl is offline
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Originally Posted by shaolin95 View Post
Not sure what causes the flapping thing but I think is more of a pressure thing since I was not in direct path to either sub's ports.
As for 10Hz I think is more of a feel thing although some test tones for some reason do have some sound but does not sound natural as it sounds too high pitched compared to 15Hz etc.
In any case I decided to move them right behind my seat and OMG the experience just went through the roof (and I almost did too! lol).
Seriously the tactile experience, the ultra low frequencies hitting you like that just makes everything a LOT better. Hard to explain but if you have the chance to do it, give it a shot. Mine are NEVER moving from there.
Not only I push them lower but the experience is just on another level..cannot really argue with that.

Last time I tried such a setup I was living in Puerto Rico and it was the sub from my first HT ever..a Kenwood HTB-503..I still remember the model as it was a gift from a very special person. And then my other sub was a Sony W400 (something like that)...of course, the difference is beyond imagination but its fun to think on how one started
Haha! I am glad you are getting such a good result from the setup. Yes, some good visceral effects can certainly make even bad movies enjoyable.

Is what you are hearing at 10Hz harmonic distortion? Or mechanical?

My first sub was an Sansui 10", followed by a DB Dynamics dual 12" push-pull and then the TN1220HO. The TN was certainly several orders of magnitude better in sound quality and extension. Two VTF-15Hs would be comparable to four TNs, which would be an amazing increase in performance.

Regards,
Nigel
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Old March 13th, 2012, 4:06 PM
Sputter Sputter is offline
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Originally Posted by Nigel_Pl View Post
Haha! I am glad you are getting such a good result from the setup. Yes, some good visceral effects can certainly make even bad movies enjoyable.

Is what you are hearing at 10Hz harmonic distortion? Or mechanical?

My first sub was an Sansui 10", followed by a DB Dynamics dual 12" push-pull and then the TN1220HO. The TN was certainly several orders of magnitude better in sound quality and extension. Two VTF-15Hs would be comparable to four TNs, which would be an amazing increase in performance.

Regards,
Nigel
If I had to guess it would be 2nd order or even 3rd?
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  #31  
Old March 13th, 2012, 6:33 PM
Dr_Hsu Dr_Hsu is offline
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If I had to guess it would be 2nd order or even 3rd?
The subsonic filter in the 15H is second order. Yes, the 15H should not have any significant acoustic output at 10 Hz. The output at that frequency are out of phase with the output from the woofer. Output at 16 Hz though should be Very Nice and pretty decent at 14, 15 Hz, especially if the room has a strong boost there (like in Shaolin95's case).

Last edited by Dr_Hsu : March 13th, 2012 at 7:44 PM.
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  #32  
Old March 13th, 2012, 7:12 PM
Nigel_Pl Nigel_Pl is offline
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Originally Posted by Sputter View Post

Sorry to disagree with you, with the HPF I doubt very much you're getting much if anything at 10hz. I get nice gain in my room but it drops at 13.5hz or even a tad higher. Since the HPF isn't a wall so it slowly drops off below tune. For useable output I don't see it.

Maybe Dr Hsu can explain it better.


P.S. @Dr Hsu, I went to bed thinking if SMS was engaged for the above graph. I know I said it wasn't but it was gnawing at me and I think it was. I had two peaks, one at 25hz and one at 32hz. Both were reduced by 5db. I'm getting old and my notes aren't as complete as they should be (age thingy). Sorry for the misinformation.

Here is a graph to show what I mean.
Hi Sputter,

That is a pretty good low end response. Any idea about the maximum clean spl at 20 and 15hz?

Regards,
Nige
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Old March 13th, 2012, 7:44 PM
shaolin95 shaolin95 is offline
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Originally Posted by Dr_Hsu View Post
The subsonic filter in the 15H is second order. Yes, the 15H should not have any significant acoustic output at 10 Hz. The output at that frequency are out of phase with the output from the woofer at that frequency. Output at 16 Hz though should be Very Nice and pretty decent at 14, 15 Hz, especially if the room has a strong boost there (like in Shaolin95's case).
So to clarify this I decided to run my tests again even now is a different location where there is not the same corner boosting but overall I love the tactile experience now.
Any to make sure I download the files since I was using an audio CD with no naming to the files to make sure I was not messing up my frequencies.
So The output is not huge but at least it registers and I think is decent unless I am not analyzing it correctly.
Playing several demo scenes the feeling when the lower end frequencies hit are hard to explain completely different from audible experience. Which frequencies...well I cannot tell but I watch the Flight of the Phoenix scene first and took a note where I felt that ultra low "sound" and then check the internet for when it is supposed to happen and it matches my experience.
How low is it digging? I dont know but it feels damn sweet!

FREQ
10hz 80.1
11hz 86.3
12.5hz 83.8
14hz 84.7
16hz 93.2
20hz 92.8
25hz 101.5
31.5hz 101.5
40hz 79
50hz 92.3
63hz 87.3
80hz 92.2
100hz 90.8
125hz 92.8
160hz 88.4
200hz 92.5

Last edited by shaolin95 : March 14th, 2012 at 6:15 AM.
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  #34  
Old March 13th, 2012, 8:22 PM
OZZ OZZ is offline
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You have a serious dip at 40Hz and 63Hz has almost as bad.
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Old March 13th, 2012, 9:30 PM
Dr_Hsu Dr_Hsu is offline
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You have a serious dip at 40Hz and 63Hz has almost as bad.
63 Hz isn't bad, but 40 Hz is low. Try moving off center - try sitting 5 ft from your right wall (the right wall as you look at the screen) and move the 15H directly behind you new chair position.
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Old March 14th, 2012, 4:16 AM
shaolin95 shaolin95 is offline
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Originally Posted by Dr_Hsu View Post
63 Hz isn't bad, but 40 Hz is low. Try moving off center - try sitting 5 ft from your right wall (the right wall as you look at the screen) and move the 15H directly behind you new chair position.
Either I made a typo (after 14 hours on the computer yesterday at work..not unlikely!) or I was more tired than I though because indeed a 79 is pretty nasty.
You know I am on a mission tonight to test that and fix it if its really there !
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Old March 14th, 2012, 5:27 AM
Sputter Sputter is offline
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Originally Posted by Nigel_Pl View Post
Hi Sputter,

That is a pretty good low end response. Any idea about the maximum clean spl at 20 and 15hz?

Regards,
Nige

I'm not a REW wizzard so unfortunately I don't have those numbers, sorry man.
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Old March 14th, 2012, 5:40 AM
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Originally Posted by shaolin95 View Post
So to clarify this I decided to run my tests again even now is a different location where there is not the same corner boosting but overall I love the tactile experience now.
Any to make sure I download the files since I was using an audio CD with no naming to the files to make sure I was not messing up my frequencies.
So The output is not huge but at least it registers and I think is decent unless I am not analyzing it correctly.
Playing several demo scenes the feeling when the lower end frequencies hit are hard to explain completely different from audible experience. Which frequencies...well I cannot tell but I watch the Flight of the Phoenix scene first and took a note where I felt that ultra low "sound" and then check the internet for when it is supposed to happen and it matches my experience.
How low is it digging? I dont know but it fells damn sweet!

FREQ
10hz 80.1
11hz 86.3
12.5hz 83.8
14hz 84.7
16hz 93.2
20hz 92.8
25hz 101.5
31.5hz 101.5
40hz 79
50hz 92.3
63hz 87.3
80hz 92.2
100hz 90.8
125hz 92.8
160hz 88.4
200hz 92.5

This thread is getting interesting .

2 questions and one comment.

Which SPL meter are you using and are you using a correction table?
SPL meters are pretty dicey the lower you go in freq.

A getto test would be to run the 10hz tone and listen, if you are hearing it then it's likely 2nd or 3rd order colouring it.

Dr. Hsu, have you measured a 10hz fundamental from this sub?

as an aside, I place my subs behind my couch facing each other about 12" apart. Time to run REW. lol I fully expect to lose my 13-14hz. We'll see
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Old March 14th, 2012, 6:00 AM
shaolin95 shaolin95 is offline
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Originally Posted by Sputter View Post
This thread is getting interesting .

2 questions and one comment.

Which SPL meter are you using and are you using a correction table?
SPL meters are pretty dicey the lower you go in freq.

A getto test would be to run the 10hz tone and listen, if you are hearing it then it's likely 2nd or 3rd order colouring it.

Dr. Hsu, have you measured a 10hz fundamental from this sub?

as an aside, I place my subs behind my couch facing each other about 12" apart. Time to run REW. lol I fully expect to lose my 13-14hz. We'll see
Yeah all of this at the mercy of the analog Radio Shack meter and correction tables so...yes...who knows. I will be getting a calibrated cm-140 in a couple of weeks though.

I think the 10hz noise was just one disc I was using.
The new files I got have no sound that I can hear at 10 hz I just see the sub moving but no sound.
Good luck with that...always fun testing..unless you find a bad freq or lose your nice settings after all the work moving around

Last edited by shaolin95 : March 14th, 2012 at 6:13 AM.
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  #40  
Old March 14th, 2012, 6:06 AM
Nigel_Pl Nigel_Pl is offline
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Originally Posted by Sputter View Post
I'm not a REW wizzard so unfortunately I don't have those numbers, sorry man.
No worries, all I have is a Radio Shack spl meter
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  #41  
Old March 14th, 2012, 6:11 AM
Nigel_Pl Nigel_Pl is offline
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Quote:
Originally Posted by Sputter View Post
This thread is getting interesting .

2 questions and one comment.

Which SPL meter are you using and are you using a correction table?
SPL meters are pretty dicey the lower you go in freq.

A getto test would be to run the 10hz tone and listen, if you are hearing it then it's likely 2nd or 3rd order colouring it.

Dr. Hsu, have you measured a 10hz fundamental from this sub?

as an aside, I place my subs behind my couch facing each other about 12" apart. Time to run REW. lol I fully expect to lose my 13-14hz. We'll see
I am sure I've read a review where Dr Hsu played a 10Hz tone on a VTF-15H for the reviewer, but I can't find the link to the review anymore.
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  #42  
Old March 14th, 2012, 6:15 AM
Nigel_Pl Nigel_Pl is offline
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Originally Posted by shaolin95 View Post
Yeah all of this at the mercy of the analog Radio Shack meter and correction tables so...yes...who knows. I will be getting a calibrated cm-140 in a couple of weeks though.

I think the 10hz noise was just one tone generator I was using.
The new files I got have no sound that I can hear at 10 hz I just see the sub moving but no sound.
Good luck with that...always fun testing..unless you find a bad freq or lose your nice settings after all the work moving around

No sound is good that low, especially if you can still feel the effects of the sub.
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  #43  
Old March 14th, 2012, 6:21 AM
shaolin95 shaolin95 is offline
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Originally Posted by Nigel_Pl View Post
No sound is good that low, especially if you can still feel the effects of the sub.
Yeah that is so far the only thing that I think validates the meter reading..that I do feel that odd effect when the low notes hit...I cannot even find a way to describe it but it is just so awesome and addictive to feel. Now I see why people go crazy adding more and more subs etc and going for ultra low frequencies.
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Old March 14th, 2012, 7:44 AM
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I have a couple graphs to post lol. They are likely to be spread over 2 posts. * No mains used, subs only*.

The first 2 graphs show both subs in a near field postion facing each other. The difference between Q-7 and Q-3 made no difference in response in regards to peaks and dips, It all stayed relative.

The bottom 2 graphs show my original position, One near field and one far field.
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  #45  
Old March 14th, 2012, 7:56 AM
Sputter Sputter is offline
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Now here is my final graph. with EQ via SMS-1.

I did countless graphs making changes to the sub settings, however I couldn't shift my seating due to my mains/surrounds positioning.

I could squeeze out a hair bit flatter but it would take a bit of time.
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Old March 14th, 2012, 8:11 AM
Dr_Hsu Dr_Hsu is offline
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Quote:
Originally Posted by Sputter View Post
This thread is getting interesting .

2 questions and one comment.

Which SPL meter are you using and are you using a correction table?
SPL meters are pretty dicey the lower you go in freq.

A getto test would be to run the 10hz tone and listen, if you are hearing it then it's likely 2nd or 3rd order colouring it.

Dr. Hsu, have you measured a 10hz fundamental from this sub?

as an aside, I place my subs behind my couch facing each other about 12" apart. Time to run REW. lol I fully expect to lose my 13-14hz. We'll see
No, no useful output at 10 Hz. As I mentioned above (post 31), the output from the 15H at 10 Hz should be practically non-existent as the port output will be cancelling the woofer output at that frequency. In sealed mode, and in a room with strong gain at 10 Hz, maybe a bit of output. If anyone wants strong output in that range, get the Eminent Technology Rotary Woofer.
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Old March 14th, 2012, 8:17 AM
shaolin95 shaolin95 is offline
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Originally Posted by Dr_Hsu View Post
No, no useful output at 10 Hz. As I mentioned above (post 31), the output from the 15H at 10 Hz should be practically non-existent as the port output will be cancelling the woofer output at that frequency. In sealed mode, and in a room with strong gain at 10 Hz, maybe a bit of output. If anyone wants strong output in that range, get the Eminent Technology Rotary Woofer.
So what I am getting might still be enough to feel it but is just due to my room basically specially up to 11hz which is stronger than my 10hz? Also, since I have them so close to my seat...maybe sealed mode can dig deeper for me? I have not tried that.
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Old March 14th, 2012, 8:18 AM
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Originally Posted by Dr_Hsu View Post
No, no useful output at 10 Hz. As I mentioned above (post 31), the output from the 15H at 10 Hz should be practically non-existent as the port output will be cancelling the woofer output at that frequency. In sealed mode, and in a room with strong gain at 10 Hz, maybe a bit of output. If anyone wants strong output in that range, get the Eminent Technology Rotary Woofer.
Let me run that by my wife.
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Old March 14th, 2012, 8:29 AM
shaolin95 shaolin95 is offline
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Let me run that by my wife.
I dont have one but looks like the only part I can afford is Motor Controller $450.00
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  #50  
Old March 14th, 2012, 8:40 AM
Nigel_Pl Nigel_Pl is offline
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My bad, it was the ULS-15 review that Dr Hsu demonstrated the 10Hz extension. Very amusing review.

http://positive-feedback.com/Issue44/hsu.htm
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Old March 14th, 2012, 8:48 AM
Dr_Hsu Dr_Hsu is offline
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Originally Posted by Sputter View Post
I have a couple graphs to post lol. They are likely to be spread over 2 posts. * No mains used, subs only*.

The first 2 graphs show both subs in a near field postion facing each other. The difference between Q-7 and Q-3 made no difference in response in regards to peaks and dips, It all stayed relative.

The bottom 2 graphs show my original position, One near field and one far field.
Thank you for all the hard work! Do you have curves of the single 15H up front? I think you have posted that before but I don't remember where...

Also, can you increase the vertical scale? it's hard to estimate the SPL at different frequency when the scale is 20 dB/div.. If you can expand it so it displays 80 to 110 dB instead of - 60 dB to +160 dB, that would be great.

Are those measurements done with the signal level and sub level settings identical? i.e., you just do the measurements with the subs in the different locations but no changes to any controls (other than varying the Q controls)?

If so, I see that you lose maybe 2 - 3 dB output below 16Hz, but gain 10 - 20 dB headroom in the 20 - 40 Hz range. Looks like at 16 Hz, the two subs behind you is still 2 - 3 dB stronger than one in front and one behind you (very hard to estimate given the 20 dB/Div scale.. ). I think I would prefer the 10 - 20 dB more headroom in the 20 - 40 Hz range to give up 2 - 3 dB below 16 Hz where the subwoofer do not have very strong output anyway.

My philosophy is to try to get as much headroom as possible over the low bass range the subwoofer is designed for. Even if it is not flat, a good EQ like you have can take care of that. When both are behind you, you should get a lot lower distortion 20 - 40 Hz for the same SPL (the two subs are driven at 1/10 (10 dB) to 1/100 (20 dB) the power to achieve the same SPL). You still get smooth flat response thanks to your SMS-1. You get a heck of a lot more headroom as well! The system should sound a lot more effortless, and a lot more dynamic. Of course, without the SMS, your current setup will sound more balanced and accurate. But, since you have the SMS, you can have your cake (flat response) and eat it too (gain 10 - 20 dB more headroom plus lower distortion at the same listening level.)
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  #52  
Old March 14th, 2012, 8:54 AM
Nigel_Pl Nigel_Pl is offline
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Originally Posted by shaolin95 View Post
I dont have one but looks like the only part I can afford is Motor Controller $450.00
Haha! They can throw in a car with each subwoofer purchase

Very impressive technology. Who knows, in a few years time something like that could be a lot cheaper.
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  #53  
Old March 14th, 2012, 8:57 AM
Dr_Hsu Dr_Hsu is offline
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Originally Posted by shaolin95 View Post
So what I am getting might still be enough to feel it but is just due to my room basically specially up to 11hz which is stronger than my 10hz? Also, since I have them so close to my seat...maybe sealed mode can dig deeper for me? I have not tried that.
You cannot hear clean 15 - 16 Hz. You just feel it. Strong output capability in that range may be what is contributing to your experience. I would not go to sealed mode simply because you will lose a lot of headroom in the 15 - 25 Hz range to get a bit more output below 15 Hz.
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Old March 14th, 2012, 9:01 AM
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Let me run that by my wife.
'But honey, if you have constipation, the rotary sub will clear out your bowels for you' I heard that high SPL in the 7 - 10 Hz range can cause brain damage, upset your body so you can have uncontrolled bowel movement...
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  #55  
Old March 14th, 2012, 9:03 AM
Nigel_Pl Nigel_Pl is offline
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Originally Posted by Dr_Hsu View Post
'But honey, if you have constipation, the rotary sub will clear out your bowels for you' I heard that high SPL in the 7 - 10 Hz range can cause brain damage, upset your body so you can have uncontrolled bowel movement...
Haha! That is so wrong!
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Old March 14th, 2012, 9:32 AM
shaolin95 shaolin95 is offline
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Originally Posted by Dr_Hsu View Post
You cannot hear clean 15 - 16 Hz. You just feel it. Strong output capability in that range may be what is contributing to your experience. I would not go to sealed mode simply because you will lose a lot of headroom in the 15 - 25 Hz range to get a bit more output below 15 Hz.
Ok so it is likely just the 16hz-15hz that is giving me that "pressure change" feeling
Since movies of course I play louder than my measurements listed...do you think that the output below 15hz I am getting is really doing much for me?
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Old March 14th, 2012, 9:45 AM
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Ok so it is likely just the 16hz-15hz that is giving me that "pressure change" feeling
Since movies of course I play louder than my measurements listed...do you think that the output below 15hz I am getting is really doing much for me?
Of course you are hitting MUCH higher SPL with the movies. With the sub directly behind you, you are probably hitting 125 - 130 dB overall (total energy summed over all the bass frequencies). That is why it's so thrilling to experience that. I felt sick after sitting in front of one 15H playing the haunting movie in our demo room... But, as you discovered, its cool to feel my pants fluttering from all that bass.

I would be very happy with what you have. Just try to see if you can improve the 40 Hz output by moving off center (and move the sub to be behind you at the new position)
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Old March 14th, 2012, 10:28 AM
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Originally Posted by Dr_Hsu View Post
Of course you are hitting MUCH higher SPL with the movies. With the sub directly behind you, you are probably hitting 125 - 130 dB overall (total energy summed over all the bass frequencies). That is why it's so thrilling to experience that. I felt sick after sitting in front of one 15H playing the haunting movie in our demo room... But, as you discovered, its cool to feel my pants fluttering from all that bass.

I would be very happy with what you have. Just try to see if you can improve the 40 Hz output by moving off center (and move the sub to be behind you at the new position)
Indeed Happy I am! I will test and if indeed is that low I will move to test..but worst case, I can live with it if I HAVE to...but I wont give up that easily
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Old March 14th, 2012, 12:07 PM
Sputter Sputter is offline
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'But honey, if you have constipation, the rotary sub will clear out your bowels for you' I heard that high SPL in the 7 - 10 Hz range can cause brain damage, upset your body so you can have uncontrolled bowel movement...
More fun than a diuretic (sp?)
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Old March 14th, 2012, 12:18 PM
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Originally Posted by Dr_Hsu View Post
Thank you for all the hard work! Do you have curves of the single 15H up front? I think you have posted that before but I don't remember where...

Also, can you increase the vertical scale? it's hard to estimate the SPL at different frequency when the scale is 20 dB/div.. If you can expand it so it displays 80 to 110 dB instead of - 60 dB to +160 dB, that would be great.

Are those measurements done with the signal level and sub level settings identical? i.e., you just do the measurements with the subs in the different locations but no changes to any controls (other than varying the Q controls)?

If so, I see that you lose maybe 2 - 3 dB output below 16Hz, but gain 10 - 20 dB headroom in the 20 - 40 Hz range. Looks like at 16 Hz, the two subs behind you is still 2 - 3 dB stronger than one in front and one behind you (very hard to estimate given the 20 dB/Div scale.. ). I think I would prefer the 10 - 20 dB more headroom in the 20 - 40 Hz range to give up 2 - 3 dB below 16 Hz where the subwoofer do not have very strong output anyway.


My philosophy is to try to get as much headroom as possible over the low bass range the subwoofer is designed for. Even if it is not flat, a good EQ like you have can take care of that. When both are behind you, you should get a lot lower distortion 20 - 40 Hz for the same SPL (the two subs are driven at 1/10 (10 dB) to 1/100 (20 dB) the power to achieve the same SPL). You still get smooth flat response thanks to your SMS-1. You get a heck of a lot more headroom as well! The system should sound a lot more effortless, and a lot more dynamic. Of course, without the SMS, your current setup will sound more balanced and accurate. But, since you have the SMS, you can have your cake (flat response) and eat it too (gain 10 - 20 dB more headroom plus lower distortion at the same listening level.)

I'll look at my graphs again. All modes/positions were done at the same signal lvl from the AVR.
No change except as you say at the Q/mode/position. Subs are gain matched and didn't change as well. I do/did have one graph of a single but it was hand graph before SMS or REW. (iirc)

Jim

P.S. meh, I didn't pay any attention to the vert scale because I was using my cursor on the REW graphs to check the numbers. . I only saved the graphs as .jpgs and not reloadable data.
Live and learn. I can do a do-over just not tonight, it's Survivor night.

Last edited by Sputter : March 14th, 2012 at 12:31 PM.
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  #61  
Old March 14th, 2012, 2:51 PM
Dr_Hsu Dr_Hsu is offline
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I'll look at my graphs again. All modes/positions were done at the same signal lvl from the AVR.
No change except as you say at the Q/mode/position. Subs are gain matched and didn't change as well. I do/did have one graph of a single but it was hand graph before SMS or REW. (iirc)

Jim

P.S. meh, I didn't pay any attention to the vert scale because I was using my cursor on the REW graphs to check the numbers. . I only saved the graphs as .jpgs and not reloadable data.
Live and learn. I can do a do-over just not tonight, it's Survivor night.
No hurry. Enjoy your Survivor night! But do you see what I mean? If you can get between 10 - 20 dB more headroom from 20 - 40 Hz, and 2 - 3 dB headroom at 16 Hz, your system will be one heck of a lot lower distortion and a lot higher headroom over frequencies that really matters. With the SMS, you will still get the same flat response with the sub located there. Win-win situation. 10 - 100 times more output between 20 - 40 Hz at no additional cost? That is fantastic. The problem with having the subs sum acoustically to get a flat response is some of the flattening is achieved by having the two subs cancel each other out. That is a very inefficient way to do it! In your case, you get 100 times more acoustic output at your listening chair around 22 - 24 Hz. That is a HUGE difference.
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Old March 14th, 2012, 4:02 PM
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No hurry. Enjoy your Survivor night! But do you see what I mean? If you can get between 10 - 20 dB more headroom from 20 - 40 Hz, and 2 - 3 dB headroom at 16 Hz, your system will be one heck of a lot lower distortion and a lot higher headroom over frequencies that really matters. With the SMS, you will still get the same flat response with the sub located there. Win-win situation. 10 - 100 times more output between 20 - 40 Hz at no additional cost? That is fantastic. The problem with having the subs sum acoustically to get a flat response is some of the flattening is achieved by having the two subs cancel each other out. That is a very inefficient way to do it! In your case, you get 100 times more acoustic output at your listening chair around 22 - 24 Hz. That is a HUGE difference.
Actually it's sinking in. Currently REW says I have 14.8db headroom at the level i was running my graphs. I didn't note what the placement difference made on the reported headroom. I'll take another stab at it in the morning.

I gots to run, the wife is calling me for survivor.
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Old March 14th, 2012, 7:08 PM
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Here are my new measurements. I was able to recover some of the 40hz power by just lowering my sitting position (was a tad high for my taste anyway) about 6" or so..pretty interesting what such a small difference can do for frequencies depending on location and subwoofer location. Not perfect but better I think.

FREQ
10hz - 80.6
11hz - 87.3
12.5hz - 84.3
14hz - 84.2
16hz - 93.2
20hz - 94.1
25hz - 102.5
31.5hz - 102.9
40hz - 88.5
50hz - 94.5
63hz - 90.3
80hz - 91
100hz - 89.5
125hz - 94.8
160hz - 87.9
200hz - 92.00

Last edited by shaolin95 : March 14th, 2012 at 8:25 PM.
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Old March 14th, 2012, 9:12 PM
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Here are my new measurements. I was able to recover some of the 40hz power by just lowering my sitting position (was a tad high for my taste anyway) about 6" or so..pretty interesting what such a small difference can do for frequencies depending on location and subwoofer location. Not perfect but better I think.

FREQ
10hz - 80.6
11hz - 87.3
12.5hz - 84.3
14hz - 84.2
16hz - 93.2
20hz - 94.1
25hz - 102.5
31.5hz - 102.9
40hz - 88.5
50hz - 94.5
63hz - 90.3
80hz - 91
100hz - 89.5
125hz - 94.8
160hz - 87.9
200hz - 92.00
That is much better. If you can equalize the system to bring down 25 and 31.5 Hz, you will have a very nice system! I personally would be quite happy with a strong 25 and 31.5 Hz. It does not sound boomy when the peak is that low in frequency. I love having a strong deep bass.
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Old March 15th, 2012, 4:06 AM
shaolin95 shaolin95 is offline
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Originally Posted by Dr_Hsu View Post
That is much better. If you can equalize the system to bring down 25 and 31.5 Hz, you will have a very nice system! I personally would be quite happy with a strong 25 and 31.5 Hz. It does not sound boomy when the peak is that low in frequency. I love having a strong deep bass.
Yeah I thought about that but I agree..I like that extra boost since its not too crazy ..gives that good pumping feeling!
Thanks for the help!
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Old March 15th, 2012, 7:48 AM
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Yeah I thought about that but I agree..I like that extra boost since its not too crazy ..gives that good pumping feeling!
Thanks for the help!
Yep. I love that extra shake...
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Old March 15th, 2012, 4:07 PM
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Today was an exercise in futility. No joy with EQ with either placements (new or old)
I developed 2 dips that I didn't have before in my old placement.
It drove me nuts . I finally cried uncle and gave up. Maybe tomorrow will be a better attempt.
I'm not fussy about having to make 10db cuts in the new placement (behind the couch). That's the variances I was getting nearfield and ~20hz was terrible as well. (measured at 90db sweeps)

I wasn't finding much difference in reported headroom through REW in any position. I'm getting 15db at the 90db sweeps. I don't know what a good number is though.

Jim
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Old March 15th, 2012, 4:36 PM
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Today was an exercise in futility. No joy with EQ with either placements (new or old)
I developed 2 dips that I didn't have before in my old placement.
It drove me nuts . I finally cried uncle and gave up. Maybe tomorrow will be a better attempt.
I'm not fussy about having to make 10db cuts in the new placement (behind the couch). That's the variances I was getting nearfield and ~20hz was terrible as well. (measured at 90db sweeps)

I wasn't finding much difference in reported headroom through REW in any position. I'm getting 15db at the 90db sweeps. I don't know what a good number is though.

Jim
Sorry to hear you are having so much trouble. I would not pay too much attention to the reported headroom. Did you manage to make the measurements without EQ but with a much narrower dB range? I wanted to see the curves you posted before but on a finer scale.
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Old March 15th, 2012, 4:41 PM
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Originally Posted by Dr_Hsu View Post
Sorry to hear you are having so much trouble. I would not pay too much attention to the reported headroom. Did you manage to make the measurements without EQ but with a much narrower dB range? I wanted to see the curves you posted before but on a finer scale.
I was so beat up today I didn't save any. I will tomorrow.
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Old March 15th, 2012, 4:46 PM
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I was so beat up today I didn't save any. I will tomorrow.
Yes, get some rest!
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Old March 15th, 2012, 7:09 PM
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I tried moving to the 38% of lenght position today for a test with the subs as well and while the 25 and 31.5 went down , overall the experience was not the same. Most of the higher frequencies went up (since I was much closer to the front speakers) but I like my previous one much more so back I went. So I think for now my current location is the one to keep and time to do some actual movie viewing. Seriously speaking , I am not sure if I would enjoy going to the movies and missing all this unless I find some uber theater
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Old March 15th, 2012, 7:20 PM
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Originally Posted by shaolin95 View Post
I tried moving to the 38% of lenght position today for a test with the subs as well and while the 25 and 31.5 went down , overall the experience was not the same. Most of the higher frequencies went up (since I was much closer to the front speakers) but I like my previous one much more so back I went. So I think for now my current location is the one to keep and time to do some actual movie viewing. Seriously speaking , I am not sure if I would enjoy going to the movies and missing all this unless I find some uber theater
I was asking you to move to your right a few feet and see if you get rid of the dip. Keep same distance from the back wall.
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Old March 15th, 2012, 7:32 PM
shaolin95 shaolin95 is offline
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I was asking you to move to your right a few feet and see if you get rid of the dip. Keep same distance from the back wall.
Yeah I did that before and it increased 40hz a bit and then moving it up or down even more but when I moved the sub behind me there, it went down quite a bit and it is too much to the sides for my liking so overall, I rather live with the slightly improved setting I posted last and be on a better location overall for my taste...at least for now. Damn acoustics...why cant we all perfectly flat rooms


BTW using both inputs on the back make no difference from using one right? I read on a SVS thread where they claim using both gives them +3db

Last edited by shaolin95 : March 15th, 2012 at 7:42 PM.
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Old March 15th, 2012, 8:17 PM
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Yeah I did that before and it increased 40hz a bit and then moving it up or down even more but when I moved the sub behind me there, it went down quite a bit and it is too much to the sides for my liking so overall, I rather live with the slightly improved setting I posted last and be on a better location overall for my taste...at least for now. Damn acoustics...why cant we all perfectly flat rooms


BTW using both inputs on the back make no difference from using one right? I read on a SVS thread where they claim using both gives them +3db
I see. Yes, be happy with the middle position!

Feeding signal to both inputs increases the sensitivity of the sub, but does not affect the maximum output capability of the sub. What subs with two inputs do is to sum the left and right input voltages. If you feed 1V into one input and 0 on the other, summing them together gives you 1/2V. If you feed the 1V into both inputs, you get 1V, or twice the voltage after summing. That translates into 6 dB more output by feeding both inputs. That just means for the same volume setting, it plays louder if the sub has not reached it's limit. The upper limit remains unchanged. Feeding both inputs does not double the amplifier's maximum output power.
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Old March 16th, 2012, 4:15 AM
shaolin95 shaolin95 is offline
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Exactly that is what I though so I didnt see the point of it but I know sometimes people do things that make no sense...more often than they should
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Old March 16th, 2012, 6:59 AM
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Dr Hsu, I must have been tired yesterday. I just checked both subs, at some point during me moving then around I had the gain turned off on one.
I can't say when, i'm glad i didn't post any of those graphs. I don't expect to make a pro reviewer anyways.

Jim
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Old March 16th, 2012, 7:16 AM
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Todays offerings

Both subs are behind my couch.
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Old March 16th, 2012, 7:51 AM
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Exactly that is what I though so I didnt see the point of it but I know sometimes people do things that make no sense...more often than they should
Exactly!
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Old March 16th, 2012, 8:04 AM
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Dr Hsu, I must have been tired yesterday. I just checked both subs, at some point during me moving then around I had the gain turned off on one.
I can't say when, i'm glad i didn't post any of those graphs. I don't expect to make a pro reviewer anyways.

Jim
Glad to hear that you found the reason why it was behaving differently yesterday!

Note that some auto EQ cannot perform the job properly if the sub's gain is too high. So, for the case with both subs behind you, you may need to lower both subs' gain some for your equalizer to work properly.

If the subs are already level matched, to lower the gain on both is easy. You do not have to move the subs. Just play one sub at a time. Turn off sub 2. Play a 40 Hz tone (or 50 Hz, does not matter what frequency so long as it's within the sub's range), adjust your receiver volume to get 83 dB on the meter. If you want it to be 6 dB lower, adjust the volume control on the sub so your meter now reads 77 dB. Now turn off sub 1 and turn on sub 2. Repeat the above - adjust the receiver's volume to get 83 dB on sub 2. Then adjust the subwoofer's volume control to get the reading down to 77 dB. Now they are both level matched but 6 dB lower in sensitivity!
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Old March 16th, 2012, 8:08 AM
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Glad to hear that you found the reason why it was behaving differently yesterday!

Note that some auto EQ cannot perform the job properly if the sub's gain is too high. So, for the case with both subs behind you, you may need to lower both subs' gain some for your equalizer to work properly.

If the subs are already level matched, to lower the gain on both is easy. You do not have to move the subs. Just play one sub at a time. Turn off sub 2. Play a 40 Hz tone (or 50 Hz, does not matter what frequency so long as it's within the sub's range), adjust your receiver's volume to get 83 dB on the meter. If you want it to be 6 dB lower, adjust the volume control on the sub so your meter now reads 77 dB. Now turn off sub 1 and turn on sub 2. Repeat the above - adjust the receiver's volume to get 83 dB on sub 2. Then adjust the subwoofer's volume control to get the reading down to 77 dB. Now they are both level matched but 6 dB lower in sensitivity!
They are gained matched and the gain knob isn't very high.
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Old March 16th, 2012, 8:10 AM
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Both subs are behind my couch.
Nice! Did you save it so that you can go back and change scale if needed?

Please do the same for the original front-back subwoofer layout.

If possible, do a difference curve - plot the difference in SPL between both behind you versus one in front + one behind you. Of course with the same EQ and Q settings for both locations. That would be by far the best way to see the difference in headroom between the two subwoofer locations.
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Old March 16th, 2012, 8:19 AM
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Originally Posted by Dr_Hsu View Post
Nice! Did you save it so that you can go back and change scale if needed?

Please do the same for the original front-back subwoofer layout.

If possible, do a difference curve - plot the difference in SPL between both behind you versus one in front + one behind you. Of course with the same EQ and Q settings for both locations. That would be by far the best way to see the difference in headroom between the two subwoofer locations.
It'll take me a couple mins :P
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Old March 16th, 2012, 8:31 AM
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graph, one positions changed.
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Old March 16th, 2012, 8:33 AM
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They are gained matched and the gain knob isn't very high.
The 15H's gain is so high that in our 31 ft x 14 ft demo room, we had the volume on a single 15H up 1/3 of one notch from minimum and - 5dB on the Pioneer receiver (VSX-1018)!

Now, if SMS can flatten the response, you are probably fine. If with both subs behind you and SMS is not able to flatten the response as well as when you had one in front and one in the back, then you want to try lowering the gain on the subs.
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Old March 16th, 2012, 8:36 AM
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The 15H's gain is so high that in our 31 ft x 14 ft demo room, we had the volume on a single 15H up 1/3 of one notch from minimum and - 5dB on the Pioneer receiver (VSX-1018)!

Now, if SMS can flatten the response, you are probably fine. If with both subs behind you and SMS is not able to flatten the response as well as when you had one in front and one in the back, then you want to try lowering the gain on the subs.
No Kidding, my gain knob on both are very touchy and barely on.
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Old March 16th, 2012, 8:38 AM
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graph, one positions changed.
How about a single sub up front versus a single sub at the back? (Boy, I am giving you a work out here! Sorry!)
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Old March 16th, 2012, 8:39 AM
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How about a single sub up front versus a single sub at the back? (Boy, I am giving you a work out here! Sorry!)
I can do that lol, one min.
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Old March 16th, 2012, 8:44 AM
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One back and one front.
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Old March 16th, 2012, 8:49 AM
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graph, one positions changed.
Between 17 and 40 Hz you have 5 - 15 dB gain in headroom with both behind you. Between 22 and 25 Hz, you have a 15 dB advantage. The subs need only 1/30 the power to give you the same SPL in this range. Distortion will be much lower at the same listening level, and you have 15 dB more headroom.
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Old March 16th, 2012, 8:51 AM
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One back and one front.
Can you make the color more different? Say one red versus one blue? Easier to see! Thanks!
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Old March 16th, 2012, 8:57 AM
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One back and one front.
I find it somewhat surprising that the mid bass is stronger with the sub up front! Based on these two curves, I would say if you can have both up front, you will get more headroom across most frequencies.

More specifically, you get 8 dB more output at 16 Hz (where the 15Hs are performing at their best - low distortion, high output), 3 dB at 20 Hz, and 5 - 15 dB gain from 38 Hz through 60 Hz!
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Old March 16th, 2012, 8:58 AM
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Back placement I lose the corner gain below 20hz. also front/back combo will be easier to eq due to the natural flatness. A trade off between the two placements?
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Old March 16th, 2012, 9:06 AM
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Back placement I lose the corner gain below 20hz. also front/back combo will be easier to eq due to the natural flatness. A trade off between the two placements?
How about showing the front only versus one front and one back? If the program allows you, raise the front only by 6 dB - simulating the both up front scenario.

Boy, you better take a week off to rest after all this!

As long as you can still EQ the system flat, it is well worthwhile to place them both up front (looks like the best case right now) if you gain 5 - 15 dB headroom from 60 Hz down.
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Old March 16th, 2012, 9:11 AM
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How about showing the front only versus one front and one back? If the program allows you, raise the front only by 6 dB - simulating the both up front scenario.

Boy, you better take a week off to rest after all this!

Hahah not a big deal, really.
Back in a min. I'll bump the front up by 6db.
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Old March 16th, 2012, 9:15 AM
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Hahah not a big deal, really.
Back in a min. I'll bump the front up by 6db.
Just to make sure we are on the same wavelength here. I do not mean turning up the gain on the front sub. I mean raising the measured curve for the one sub up front by 6 dB.
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Old March 16th, 2012, 9:16 AM
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Are you usiong REW for those graphs? I want to do that too
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Old March 16th, 2012, 9:17 AM
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+6db front only
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Old March 16th, 2012, 9:18 AM
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Are you usiong REW for those graphs? I want to do that too
Yes.
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Old March 16th, 2012, 9:19 AM
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Just to make sure we are on the same wavelength here. I do not mean turning up the gain on the front sub. I mean raising the measured curve for the one sub up front by 6 dB.
I re-calibrated REW for an additional +6 as i was measuring at 90db, now at 96db.
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Old March 16th, 2012, 9:22 AM
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I re-calibrated REW for an additional +6 as i was measuring at 90db, now at 96db.
Please graph the +6 dB front curve together with just the one front + one back (your original configuration). Thanks!
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Old March 16th, 2012, 9:28 AM
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Please graph the +6 dB front curve together with just the one front + one back (your original configuration). Thanks!
Back + Front
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Old March 16th, 2012, 9:32 AM
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Back + Front
No, that is not what I meant. I meant put two graphs - 96 dB for one sub up front only, versus 90 dB for one sub up front + one sub behind.
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Old March 16th, 2012, 9:34 AM
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No, that is not what I meant. I meant put two graphs - 96 dB for one sub up front only, versus 90 dB for one sub up front + one sub behind.
sec
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Old March 16th, 2012, 9:48 AM
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front vs front/back
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Old March 16th, 2012, 9:49 AM
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At 96 db crap is flying off my shelves.

When I say 96db that's 96db at my seat, my sub is 13 feet away.
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Old March 16th, 2012, 9:50 AM
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Back + Front
No, that is not what I meant. I meant put two graphs - 96 dB for one sub up front only, versus 90 dB for one sub up front + one sub behind.

The rationale behind this is we want to compare two subs up front versus one sub up front + one sub behind. Having two subs up front is just like raising one sub up front by 6 dB. Hence I want to compared 96 dB for one sub up front versus 90 dB one sub up front + one sub at the back.
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Old March 16th, 2012, 9:57 AM
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No, that is not what I meant. I meant put two graphs - 96 dB for one sub up front only, versus 90 dB for one sub up front + one sub behind.

The rationale behind this is we want to compare two subs up front versus one sub up front + one sub behind. Having two subs up front is just like raising one sub up front by 6 dB. Hence I want to compared 96 dB for one sub up front versus 90 dB one sub up front + one sub at the back.

Right. The top line is front sub at 96db the lower line is both subs back and front at 90db
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Old March 16th, 2012, 10:04 AM
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front vs front/back
Very nice! You have:

Hz Additional Output
16 7 dB
20 11 dB
22 13 dB
28 8 dB
30 6 dB
40 12 dB
50 8 dB
60 6 dB

That is a pretty darned good increase in headroom! You need between 4 to 8 15Hs with 2 front + 2 back to 4 front + 4 back to get the same headroom as having both up front!

Put both subs up front and EQ your system. You now have a TOTALLY AWESOME system!
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Old March 16th, 2012, 10:07 AM
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Very nice! You have:

Hz Additional Output
16 7 dB
20 11 dB
22 13 dB
28 8 dB
30 6 dB
40 12 dB
50 8 dB
60 6 dB

That is a pretty darned good increase in headroom! You need between 4 to 8 15Hs with 2 front + 2 back to 4 front + 4 back to get the same headroom as having both up front!

Put both subs up front and EQ your system.
I can do that. I have enough space in the opposite corner for it. I did have one there way back but before REW and maybe before I bought the second. (that was over a year ago).
I'll post a non EQ'ed graph in a couple mins.
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Old March 16th, 2012, 10:22 AM
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both front 90db Pretty ugly but lots to work with.
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Old March 16th, 2012, 10:32 AM
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both front 90db Pretty ugly but lots to work with.
That does not look good. Can you stack both subs in the same great corner?
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Old March 16th, 2012, 10:50 AM
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That does not look good. Can you stack both subs in the same great corner?
Unfortunately not that corner, the best I could is side by side there.

P.S. however, it's not out of the realm of possibilty..lol (on second thought)

Last edited by Sputter : March 16th, 2012 at 11:10 AM. Reason: added P.S.
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Old March 16th, 2012, 11:24 AM
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Unfortunately not that corner, the best I could is side by side there.

P.S. however, it's not out of the realm of possibilty..lol (on second thought)
If you can put them there side by side, give that a try!
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Old March 16th, 2012, 11:28 AM
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If you can put them there side by side, give that a try!

I can do that, also i was looking at the shelving which I never really liked, I doubt my wife will care when I explain things to her. (Kerry is good that way).

Jim
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Old March 16th, 2012, 11:38 AM
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side by side
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Old March 16th, 2012, 11:46 AM
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if you feel there are gains to be made stacking over side by side then i have no issues taking down a couple shelves.
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Old March 16th, 2012, 12:01 PM
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side by side
I am confused. Are these tested at the same level on REW and on the subs? I see over 10 dB lower level overall. Deep bass below 20 Hz seems to be falling off more steeply. ???
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Old March 16th, 2012, 12:09 PM
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I am confused. Are these tested at the same level on REW and on the subs? I see over 10 dB lower level overall. Deep bass below 20 Hz seems to be falling off more steeply. ???
One sec, I switched to Mode-2 this is mode-1
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Old March 16th, 2012, 12:10 PM
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Are you using an external card with REW? I was going to set it up but then I read that most cards filter at 20hz so I wanted to know what I get below that even it its not much after 15Hz.
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Old March 16th, 2012, 12:12 PM
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Originally Posted by shaolin95 View Post
Are you using an external card with REW? I was going to set it up but then I read that most cards filter at 20hz so I wanted to know what I get below that even it its not much after 15Hz.
I use a Mobile-pre
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Old March 16th, 2012, 12:19 PM
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Cool. Thanks.
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Old March 16th, 2012, 12:30 PM
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welcome man
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Old March 16th, 2012, 12:36 PM
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One sec, I switched to Mode-2 this is mode-1
Still does not make sense. If the REW output is still the same as for the single sub up front, 90 dB, why is output between 40 - 50 Hz a lot lower with two subs?? Can you measure each sub separately in that front position? Actually, measure sub 1, then sub 2, then sub1 + sub 2 in that front position.
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Old March 16th, 2012, 1:47 PM
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the subs side by side or one in each corner?
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Old March 16th, 2012, 1:51 PM
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the subs side by side or one in each corner?
Side by side. If the two subs measure very differently, try swapping the positions and see if the second sub measures the same in the other position.

Sorry for asking you to do so much work!
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Old March 16th, 2012, 2:00 PM
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Side by side. If the two subs measure very differently, try swapping the positions and see if the second sub measures the same in the other position.

Sorry for asking you to do so much work!
It's interesting.
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Old March 16th, 2012, 2:12 PM
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Both together , green trace.

* the orientation is different, they fire into the room instead where the single front fired into the wall.
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Old March 16th, 2012, 2:19 PM
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It's interesting.
It is strange that both curves are now much lower than on posting #92 when you have a single sub up front. Can you put the red curve from post #92 together with these two?

From what I can see, the new reading (higher of the two curves) are much lower than post #92's red curve:

Hz dB less
15 2
20 2
30 3
40 5
50 8
60 6
70 9

Does REW send a fixed output level or adjusts each time you re-run the test?
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Old March 16th, 2012, 2:23 PM
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Originally Posted by Dr_Hsu View Post
It is strange that both curves are now much lower than on posting #92 when you have a single sub up front. Can you put the red curve from post #92 together with these two?

From what I can see, the new reading (higher of the two curves) are these much lower than post #92's red curve:

Hz dB less
15 2
20 2
30 3
40 5
50 8
60 6
70 9
Here is the original facing the wall orientation.
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  #130  
Old March 16th, 2012, 2:29 PM
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Originally Posted by Sputter View Post
Both together , green trace.

* the orientation is different, they fire into the room instead where the single front fired into the wall.
What is the difference between this new green curve and post #118? Are they not supposed to be the same?

The single firing into the wall seemed better (more output above 40 Hz, a lot more), so can you try firing both into the wall?
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Old March 16th, 2012, 2:32 PM
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Originally Posted by Dr_Hsu View Post
It is strange that both curves are now much lower than on posting #92 when you have a single sub up front. Can you put the red curve from post #92 together with these two?

From what I can see, the new reading (higher of the two curves) are much lower than post #92's red curve:

Hz dB less
15 2
20 2
30 3
40 5
50 8
60 6
70 9

Does REW send a fixed output level or adjusts each time you re-run the test?
Far as I know it should be the same unless I recalibrate it
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Old March 16th, 2012, 2:37 PM
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Here is the original facing the wall orientation.
That graph should take us back where we were , firing towards the wall. showing one trace for each sub and then showing them summed.
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Old March 16th, 2012, 2:40 PM
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Here is the original facing the wall orientation.
Oh, good. You beat me to it! The different scale threw me off (one is 5 dB/div, the other is 10 dB/Div). Actually facing the wall or facing into the room does not make a huge difference.

OK. I would say both up front next to each other looks great. I would just face them into the room - I think that would have a better WAF factor! Now you just have to equalize this flat. You should get huge headroom across a broad range of frequencies (as mentioned above, 6 - 13 dB more headroom than one on front and one in the back, from below 15 Hz to 70 Hz).

How high are you running the sub up to? Looks like the headroom above 50 Hz drops off rapidly. Maybe advantages to put an MBM behind you to complement the pair of 15Hs up front.

Looking at the 15H response behind your seating area, response is reasonably flat from 50 to 90 Hz. Hence a MBM back there should give you a very good uniform coverage from 50 Hz up. By not letting the 15Hs up front go up above 50 Hz, you don't suffer from the 90 Hz dip, and frees up the amplifier power in the 15Hs to just work from 50 Hz down where their new found super high headroom is taken full advantage of. Note that with the MBM-15H combo, we are no longer making them acoustically cancel each other to get the flatter response. Each is covering their own respective range where they are reasonably flat, and working VERY efficiently. Totally different approach. FAR higher headroom and lower distortion with the 15H-MBM combo.

Last edited by Dr_Hsu : March 16th, 2012 at 3:11 PM. Reason: More thoughts..
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  #134  
Old March 16th, 2012, 2:44 PM
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Oh, good. You beat me to it! The different scale threw me off (one is 5 dB/div, the other is 10 dB/Div). Actually facing the wall or facing into the room does not make a huge difference.

OK. I would say both up front next to each other looks great. I would just face them into the room - I think that would have a better WAF factor! Now you just have to equalize this flat. You should get huge headroom across a broad range of frequencies (as mentioned above, 6 - 13 dB more headroom than one on front and one in the back, from below 15 Hz to 70 Hz).
Would Stacking them create a better result? I suppose it's the same thing being co-located?
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Old March 16th, 2012, 3:33 PM
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Would Stacking them create a better result? I suppose it's the same thing being co-located?
I don't think it would make much difference. So, since it's heavy, I would suggest not doing it unless you feel that would look much better aesthetically.
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Old March 16th, 2012, 3:44 PM
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I don't think it would make much difference. So, since it's heavy, I would suggest not doing it unless you feel that would look much better aesthetically.
It would look kinda sweet, not tonight though. I'm going to work on this eqing and call it a night or maybe a movie later

I appreciate the time you took in guiding me through this. Man, what do people do that can't do accurate measurements...
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Old March 16th, 2012, 3:56 PM
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It would look kinda sweet, not tonight though. I'm going to work on this eqing and call it a night or maybe a movie later

I appreciate the time you took in guiding me through this. Man, what do people do that can't do accurate measurements...
A less than optimal system?
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Old March 16th, 2012, 4:07 PM
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A less than optimal system?
I have a few questions about what we did and why, not right now though. I need some time to digest.
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Old March 16th, 2012, 4:25 PM
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I have a few questions about what we did and why, not right now though. I need some time to digest.
Have a great weekend! Post when you are ready for the Words of Wisdom
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Old March 16th, 2012, 4:30 PM
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Have a great weekend! Post when you are ready for the Words of Wisdom
You as well, and count on the questions.
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Old March 16th, 2012, 4:53 PM
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So I was thinking, since moving up and down also makes a difference..is it the same effect if I move the subwoofer higher for example? I assume it would be.
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Old March 16th, 2012, 5:10 PM
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So I was thinking, since moving up and down also makes a difference..is it the same effect if I move the subwoofer higher for example? I assume it would be.
Some people like risers. I haven't seen any decent graphs of before and after however.

I'm sorry we totally hijacked your thread.
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Old March 16th, 2012, 5:50 PM
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I am almost done with my setup mate, I am learning from your own process as well so no worries.
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Old March 16th, 2012, 5:53 PM
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So I was thinking, since moving up and down also makes a difference..is it the same effect if I move the subwoofer higher for example? I assume it would be.
I think it's just a matter of your ear relative to the floor and ceiling. As SPUTTER said, I have not seen any well documented measurements.
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Old March 16th, 2012, 6:02 PM
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I am almost done with my setup mate, I am learning from your own process as well so no worries.
You sounded like an Australian! When I was in Australia last year, I find it hard to get used to their very frequent use of 'No worries'.
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Old March 16th, 2012, 6:23 PM
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First time I ever get that..one more to my mix of accents and words. I am from Puerto Rico with an Argentinian access in Spanish , with a "who knows" English Accent and now write in Australian!
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Old March 16th, 2012, 6:34 PM
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First time I ever get that..one more to my mix of accents and words. I am from Puerto Rico with an Argentinian access in Spanish , with a "who knows" English Accent and now write in Australian!
No worries, Mate!
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Old March 16th, 2012, 9:03 PM
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No worries, Mate!

Just fixed my speaker placement a bit today to fine tune the system since I am covered for now subwoofer wise with that little monster I got from you!
Tomorrow I will actually do some movie watching...but sometimes the tweaking is actually more addictive than the movies
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Old March 17th, 2012, 12:04 PM
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Doctor...one question...when I open the door in front I told you I get 4db more at 16Hz.
I do have a door the same size on the back which I sealed with a gypsum board panel but I am wondering how that could affect frequency as well. Damn I am sure I need to try it so it is almost impossible to predict ...so guess I have work today!
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Old March 17th, 2012, 3:08 PM
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Doctor...one question...when I open the door in front I told you I get 4db more at 16Hz.
I do have a door the same size on the back which I sealed with a gypsum board panel but I am wondering how that could affect frequency as well. Damn I am sure I need to try it so it is almost impossible to predict ...so guess I have work today!
To your side, or behind you? Can you post a drawing that includes the space behind that door?
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Old March 17th, 2012, 3:30 PM
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To your side, or behind you? Can you post a drawing that includes the space behind that door?
Sure , I am finishing a 3D rendering of my room. I will post it as soon as I get home but its to the back near the area where that 20hz peak is.
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Old March 17th, 2012, 3:44 PM
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Sure , I am finishing a 3D rendering of my room. I will post it as soon as I get home but its to the back near the area where that 20hz peak is.
Sounds good.
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Old March 17th, 2012, 3:50 PM
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You want to know the dimensions on the other side of this room basically..right?
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Old March 17th, 2012, 4:48 PM
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Ok this is my full layout..I hope is clear. First time using that program
That door way on the back is the one currently blocked.
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Old March 17th, 2012, 6:27 PM
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Ok this is my full layout..I hope is clear. First time using that program
That door way on the back is the one currently blocked.
So, right now, the 3' door to the left of the front left speaker is open, and so is the 1' 11" doorway, but the 3' 2" doorway is blocked?

Your 40 Hz dip is probably due to the fact that you are 7 ft from the left and right wall. Try sitting 14 ft from the front wall (screen wall) and see if 40 Hz is better (The bounce off the front wall reinforces 40 Hz while bounce off the side walls cancel). 14 ft from the back wall works too, if you prefer to move back rather than move forward.
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Old March 17th, 2012, 10:39 PM
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So, right now, the 3' door to the left of the front left speaker is open, and so is the 1' 11" doorway, but the 3' 2" doorway is blocked?
Yes that was the the configuration I had but I decided to open the back door today for testing and I think is a keeper but lets see you what you think.

I tried moving forward to 14' earlier and yes 40Hz improved a lot although 160 and 200 took a dive but also did the ULF areas so overall it was not a compromise I wanted to take since being that close also was going to make me reduce my screen size so the cons were more than the pros for me.

Here are my results from today. A VERY interesting boost from so low end frequencies but 10hz and 11hz both went down which I guess is fine since they are not that high to begin with so I think focusing on the more useful ones is a better choice but lets see what you think from all 3.
#1 is Back door opened and Front Door closed
#2 is Both Doors opened (seems to give me the biggest impact like that 14hz)
#3 is my previous setup Back Door closed and Front Door opened.
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Last edited by shaolin95 : March 17th, 2012 at 10:58 PM.
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  #157  
Old March 18th, 2012, 9:27 AM
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Yes that was the the configuration I had but I decided to open the back door today for testing and I think is a keeper but lets see you what you think.

I tried moving forward to 14' earlier and yes 40Hz improved a lot although 160 and 200 took a dive but also did the ULF areas so overall it was not a compromise I wanted to take since being that close also was going to make me reduce my screen size so the cons were more than the pros for me.

Here are my results from today. A VERY interesting boost from so low end frequencies but 10hz and 11hz both went down which I guess is fine since they are not that high to begin with so I think focusing on the more useful ones is a better choice but lets see what you think from all 3.
#1 is Back door opened and Front Door closed
#2 is Both Doors opened (seems to give me the biggest impact like that 14hz)
#3 is my previous setup Back Door closed and Front Door opened.
Both doors open it is!
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Old March 18th, 2012, 9:44 AM
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Both doors open it is!
Indeed!
My movie demos yesterday went up another level of impact!
I did notice that in the spinning airplane scene for Flight of the Phoenix ..I "think" like some thing is not there that was there before when my 10-11hz output was higher...but I forgot to check with the door closed which I will do tomorrow..although I think it is just a mind game since that 14Hz and even the 12 is much higher than what I had before and boy it makes a huge impact difference and that special "feeling" of low hz

Last edited by shaolin95 : March 18th, 2012 at 7:26 PM.
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  #159  
Old March 26th, 2012, 7:09 PM
shaolin95 shaolin95 is offline
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I got a better response now in my opinion. I was able to fix the 40 and 100 which where weaker and got a few dbs here and there so now everything is at 90 or above all the way down to 12.5Hz. I think that is pretty cool and I could feel it nicely today so I think I am keeping this new setup. Maybe is not drastic but it gives me peace of mind
Just a little crazy thinking using one available gypsum board placed on the back sort of creating a fake partial wall. Love acoustics!
I added my previous best as a comparison (2nd image)
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  #160  
Old March 26th, 2012, 8:14 PM
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Originally Posted by shaolin95 View Post
I got a better response now in my opinion. I was able to fix the 40 and 100 which where weaker and got a few dbs here and there so now everything is at 90 or above all the way down to 12.5Hz. I think that is pretty cool and I could feel it nicely today so I think I am keeping this new setup. Maybe is not drastic but it gives me peace of mind
Just a little crazy thinking using one available gypsum board placed on the back sort of creating a fake partial wall. Love acoustics!
I added my previous best as a comparison (2nd image)
That is cool! How did you get the 40 Hz level up?
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  #161  
Old March 26th, 2012, 8:19 PM
shaolin95 shaolin95 is offline
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Moving that fake partial wall back and forth had different effects on some frequencies and specially in my final location (for now lol) it gave me that boost so when I saw all those in 90s I was one happy camper.
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  #162  
Old April 3rd, 2012, 7:01 PM
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One more test for fun with stacked subwoofers (mfw15 on top).
#1 is Stacked
#2 is my previous favorite one
I am not sure what to think...tactile experience is of course bigger and for some reason the deepest notes that..pressure thingy feels stronger yet I lost SPL at 16hz and 12hz but gained decently at 20hz and above. I think the MFW15 weight on top of the VTF helps it when the action gets louder to make the cabinet even more solid which at the test volumes is something that may not come into play..that is my theory as to why the lower SPL in the ultra low frequencies yet it feels bigger during the movie.
What do you think?
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  #163  
Old April 3rd, 2012, 11:40 PM
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Originally Posted by shaolin95 View Post
One more test for fun with stacked subwoofers (mfw15 on top).
#1 is Stacked
#2 is my previous favorite one
I am not sure what to think...tactile experience is of course bigger and for some reason the deepest notes that..pressure thingy feels stronger yet I lost SPL at 16hz and 12hz but gained decently at 20hz and above. I think the MFW15 weight on top of the VTF helps it when the action gets louder to make the cabinet even more solid which at the test volumes is something that may not come into play..that is my theory as to why the lower SPL in the ultra low frequencies yet it feels bigger during the movie.
What do you think?
You have increased mid bass by 3 - 7 dB while reducing 16 Hz and below. This new balance is a lot more skewed toward mid bass.
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  #164  
Old April 4th, 2012, 4:24 AM
shaolin95 shaolin95 is offline
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So I guess its back to the floor
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  #165  
Old April 4th, 2012, 7:15 AM
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So I guess its back to the floor
I think so. Boy! You must be pretty buffed by now having moved the subs around so much!
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  #166  
Old April 4th, 2012, 7:40 AM
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I think so. Boy! You must be pretty buffed by now having moved the subs around so much!
Does the word hernia ring a bell?
I think it was not a good idea to have the MFW shooting right behind my head. Like I didnt feel anything bad but this morning i woke up all unbalanced so I think it did affect me ...so down it goes
I need to think of something else to try while someone sends me some awesome treat I want ...hehehe

Do you think the extra weight helped the VTF in those lower frequencies when playing movies at much louder levels by making the enclosure even more solid with less movement or something? I am just trying to understand why I felt many of the bottom "sounds" like tighter and stronger. Maybe placebo...who knows
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  #167  
Old April 4th, 2012, 2:29 PM
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Does the word hernia ring a bell?
I think it was not a good idea to have the MFW shooting right behind my head. Like I didnt feel anything bad but this morning i woke up all unbalanced so I think it did affect me ...so down it goes
I need to think of something else to try while someone sends me some awesome treat I want ...hehehe

Do you think the extra weight helped the VTF in those lower frequencies when playing movies at much louder levels by making the enclosure even more solid with less movement or something? I am just trying to understand why I felt many of the bottom "sounds" like tighter and stronger. Maybe placebo...who knows
When the balance is more mid bass, one perceive it as 'tighter' because you will have more harmonic details than the original (emphasis on the transient part of the bass). That is kind of what happens when you turn the Q lower - the deep bass rolls off more in the lower Q setting, emphasizing the mid bass more, and it sounds tighter.
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  #168  
Old April 4th, 2012, 2:47 PM
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Oh yeah but I mean the very bottom end , that one that is more feeling than sound that I thought would be doing less actually felt more...I am going to test at actual movie playing levels to see what is the deal.
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  #169  
Old April 4th, 2012, 4:54 PM
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Oh yeah but I mean the very bottom end , that one that is more feeling than sound that I thought would be doing less actually felt more...I am going to test at actual movie playing levels to see what is the deal.
Let me know what you find...
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  #170  
Old April 5th, 2012, 11:37 AM
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I will have to rest because I am sure I made a mistake. I saw a 1 db gain at 16hz and 4db gain at 20hz but somehow I dont believe that is accurate. I was not feeling very well...I think my experiment the other day was a bit stupid as I had to put my ear to close to the sub to read the spl and it was so I woke up with vertigo and lightheaded...never again
I also updated my current numbers as my ear is a bit higher than I though on that chair which changes mostly the 40hz and 100hz for me ..as well as 16hz...didnt notice any other changes when moving up and down.

All fun...still rocks..until Santa Delivers !
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  #171  
Old April 5th, 2012, 3:25 PM
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I will have to rest because I am sure I made a mistake. I saw a 1 db gain at 16hz and 4db gain at 20hz but somehow I dont believe that is accurate. I was not feeling very well...I think my experiment the other day was a bit stupid as I had to put my ear to close to the sub to read the spl and it was so I woke up with vertigo and lightheaded...never again
I also updated my current numbers as my ear is a bit higher than I though on that chair which changes mostly the 40hz and 100hz for me ..as well as 16hz...didnt notice any other changes when moving up and down.

All fun...still rocks..until Santa Delivers !
Oh Dear. Did you sign the waiver I sent you? Don't wanna get sued for getting you sick! Rest and get well!
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  #172  
Old April 5th, 2012, 4:23 PM
shaolin95 shaolin95 is offline
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Oh Dear. Did you sign the waiver I sent you? Don't wanna get sued for getting you sick! Rest and get well!
Darn it lucky for you it was the MWF15 the one hitting me so I think suing wont get me much Thanks
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