When does port noise become a problem for VTF3.3?

[tman]

I'm pretty happy with my VTF3.3, have had it in Max Output mode for last 2 years and it's been underwhelmed by my 5500cuft room. Moving it to Max Extension Mode and wondering where that kicks in. My sub Volume is set in about the 10 o'clock position. The amp calibrated by Audyssey and verified manually was at -6dB with Max Extension and I just adjusted it to 0dB to cover the 4dB loss with Max Extension and give it slight bass heaviness for movies. I typically watch movies at -16dB, occassionally have to go toward -10dB. Should I expect port noise in Max Extension??? When and what to listen for. Any advise on what to play and listen for would be appreciated. I have some good LFE disks including the Hsu calibration disk, Master and Commander, LOTR, Incredibles and can rent WOTR as needed.

[tman]

The amp calibrated by Audyssey and verified manually was at -6dB with Max Output and I just adjusted it to 0dB to cover the 4dB loss with Max Extension and give it slight bass heaviness for movies. I typically watch movies at -16dB, occassionally have to go toward -10dB. Should I expect port noise in Max Extension??? What's a good set of movie scenes to watch (other than WOTR) that will exhibit port noise if it is a problem and what to listen for.

[shadyJ]

You can't really do better than the 16 hertz test tone on the CD which Hsu sends with its subs. If you turn your sub up high enough while playing that CD, you will eventually induce chuffing. Just using that track to see which mode produces chuffing at a lower volume level might be the most straight forward way of accomplishing your goal.

If you want to use real material to induce shuffing, one of the best movie scenes might be the lab scene in the film Pulse, which occurs at 1:11:58 in the movie. It has a strong, continuous 15 to 20 hertz sound which exposes the limitations of most subwoofers, and has them begging for mercy (my ULS's, on the other hand, loves it and begs for more!). Here is a waterfall (http://img.photobucket.com/albums/v24/weezR/Waterfall%20SPL/Pulse_ch15_1-1.jpg) for that scene.

Movies like Master and Commander won't be as good for getting your sub to chuff, because the bass happens in short bursts. You want a continuous low frequency.

[Bill Mitchell]

tman, you raise an interesting question. With corner placement of the sub, tones under 20Hz in MaxExtension mode energize resonant frequencies in my house. So much so that on the Saint-Saens Organ Symphony on the test disk I stop raising the volume long before I hear any stress from the sub, to limit the house vibration. With just the one port open, it does move a lot of air.

I don't quite understand what you mean when you write that you raised the sub trim on the AVR to adjust for a 4dB drop in MaxExtension mode. Did you measure the 4dB drop yourself? Are you taking this from published data on the difference between MaxOutput and MaxExtension? I would have thought that, if you reran the Audyssey setup after changing to MaxExtension mode, Audyssey would have adjusted the sub trim for the volume it measures in your room.

[tman]

Thanks for feedback.

Re Bill's questions, I didn't measure the 4dB myself. I think there are other threads here where people quote a rougly 4dB difference between Max Extension and Max Output. I've seen some posts by Peter Maercks or one of the other Hsu people quoting 4dB as an approximate delta. You are right I really should be calibrating and then deciding whether to bump it up a little. I plan to do that on the weekend when my wife and young kids are out of the house. My kids are good at freezing in place when test tones play. My wife is either unsympathetic to the need for calibration or jealous of the attention the sub+speakers recieve so she usually destroys the tests... During the week I plan to just bump it up a few dB and see whether the port noise is there, then test again during the weekend.

p.s. My sub too is corner loaded...

[skool]

Hi TMAN,

Do you have large openings in your current HT room? How large is the space including the openings? Is the sub place nearfield? By underwhelmed, what do you mean? I am not sure what you're trying to achieve by switching to Maximum Extension since you feel that MO mode is not satisfactory. Even under ME mode, I would not recommend adjusting the trim under maximum extension mode. You will risk clipping your subs at loud volume.

Do you a SPL meter that you can verify Audyssey's bass trim? Since Audyssey tend to calibrate for a "flat" frequency response, I would stick with MO mode and increase your trim 2-3 dB. Try it and see.

If you're not satisfactory, try using the VTF3.3 nearfield.

[tman]

Do you have large openings in your current HT room? How large is the space including the openings?

No large openings, but the room is pretty large. Long axis of room is 38', short axis is 19', ceiling is about 8'. It is a combination kitchen, dining, living room (like a loft). I calculated about 5500 cu ft room. There is a 3' wide hallway opening along one of the longer walls.
My kitchen, dining, are on one side of this hallway opening (19' x 23').

My living area is on the other side of the hallway (19' deep, about 12' wide). In the living area, next to the hallway are my L,C,R speaker around a 46" TV and then (in the corner) Hsu VTF3.3. We sit between 10 and 15 ft back from the LCD within a listening area 10 ft wide. We actually have our sofa and love seat facing each other on the two sides of the living space. We will frequently lie down on them and watch TV as though they were bedding. There are recliner and other chairs further from the TV (about 15 feet back) which are for whoever didn't get a sofa to lie down on or was unwilling to lie down on someone else (our kids are shameless).

Is the sub place nearfield?

As I have described it, the sub is corner loaded to the front right of the listening space. Distance to listeners is probably between 10 and 20 ft. from the closest listener (sleeping in the Love seat on the right side of the listening space, with the sub a few feet from their feet) to the furthest (in a chair at the back left of the listening area. As a result of the large listening area, the ratio of direct to reflected will differ. The flooring is wood throughout the space, the walls are all insulated with fiberglass blow in.

By underwhelmed, what do you mean?

The sub is underwhelmed by the space in Max Output mode (the sub iitself is not "underwhelming"). It came, it saw, it kicked ass. It is trying to keep up with the detailed delivery of Ascend Sierra-1's (crossed over at 60Hz). Though I prefer music in 2-channel audio, I find the sub works quite well on music of any variety I try (from Bhimsen Joshi and Veena Sahastrabudhe to Manu Chao and Noir Desir to Bartok to NIN to Zeppelin and Hendrix and onwards). I will hurt my ears with the sub before I find it unable to keep up with the speakers and amp. Again, the adjustment on my Denon is set at -6dB for the sub and the volume dial on the sub is at 10 o'clock. Obviously I should take time to dial toward 9 o'clock and make more positive correction on the sub, but have not had time to do that.

I am not sure what you're trying to achieve by switching to Maximum Extension since you feel that MO mode is not satisfactory.

MO is quite satisfactory, however if you listen to a scene in Master and Commander in MO, you do not get as much LFE as I would like which affects the realism and oomph quite dramatically. Even at low volume level setting (-33dB on the receiver) the Hsu in ME is quite impressive in terms of the depiction of low frequency. Hence my comment about being a satisified Hsu customer wanting to experiment with the limits of the sub as I switch it over to ME for the first time.

Even under ME mode, I would not recommend adjusting the trim under maximum extension mode. You will risk clipping your subs at loud volume.

Do you a SPL meter that you can verify Audyssey's bass trim?

Yes. I have and have used it. I have set crossover higher and used Rat Shack manual meter and used the manual noise signals from the Denon. I have not gone and plotted out each frequency with test tones and made corrections to the Rat Shack meter for low frequency, though.

Since Audyssey tend to calibrate for a "flat" frequency response, I would stick with MO mode and increase your trim 2-3 dB. Try it and see.

I have tried small adjustments to trim. For music I prefer the flat response. For home movie, I have not in 2 years made up my mind on that one, but I have listened with MO bumped up enough to have a good sense how it has changed the sound when I start listening to ME and trying to decide if it sounds okay.

If you're not satisfactory, try using the VTF3.3 nearfield.

Near field is not an option due to (1) the odd listening layout and (2) because it is a multifunction room with a significant collection of south-east asian art and antiques on display. 2nd sub is also not an option right now. Again, I am not trying to get more output after 2 years of use, just want to experiment with the other thing this sub is designed to do to identify whether the port noise is a concern at reasonable volumes in the large space or not. Clipping is not from my experience with Max Extension mode much of a concern. The speaker and sub can play fine at much higher volumes (I have actually set up a limiter on the Denon at 0dB which is already deafeningly loud from most sources).

If the Turbo was still manufactured I would probably look at that as a backup option as well, but for now I want to focus on testing whether the Max Extension has port noise or not.

[tman]

Do you have large openings in your current HT room? How large is the space including the openings?

No large openings, but the room is pretty large. Long axis of room is 38', short axis is 19', ceiling is about 8'. It is a combination kitchen, dining, living room (like a loft). I calculated about 5500 cu ft room. There is a 3' wide hallway opening along one of the longer walls.
My kitchen, dining, are on one side of this hallway opening (19' x 23').

My living area is on the other side of the hallway (19' deep, about 12' wide). In the living area, next to the hallway are my L,C,R speaker around a 46" TV and then (in the corner) Hsu VTF3.3. We sit between 10 and 15 ft back from the LCD within a listening area 10 ft wide. We actually have our sofa and love seat facing each other on the two sides of the living space. We will frequently lie down on them and watch TV as though they were bedding. There are recliner and other chairs further from the TV (about 15 feet back) which are for whoever didn't get a sofa to lie down on or was unwilling to lie down on someone else (our kids are shameless).

Is the sub place nearfield?

As I have described it, the sub is corner loaded to the front right of the listening space. Distance to listeners is probably between 10 and 20 ft. from the closest listener (sleeping in the Love seat on the right side of the listening space, with the sub a few feet from their feet) to the furthest (in a chair at the back left of the listening area. As a result of the large listening area, the ratio of direct to reflected will differ. The flooring is wood throughout the space, the walls are all insulated with fiberglass blow in.

By underwhelmed, what do you mean?

The sub is underwhelmed by the space in Max Output mode (the sub iitself is not "underwhelming"). It came, it saw, it kicked ass. It is trying to keep up with the detailed delivery of Ascend Sierra-1's (crossed over at 60Hz). Though I prefer music in 2-channel audio, I find the sub works quite well on music of any variety I try (from Bhimsen Joshi and Veena Sahastrabudhe to Manu Chao and Noir Desir to Bartok to NIN to Zeppelin and Hendrix and onwards). I will hurt my ears with the sub before I find it unable to keep up with the speakers and amp. Again, the adjustment on my Denon is set at -6dB for the sub and the volume dial on the sub is at 10 o'clock. Obviously I should take time to dial toward 9 o'clock and make more positive correction on the sub, but have not had time to do that.

I am not sure what you're trying to achieve by switching to Maximum Extension since you feel that MO mode is not satisfactory.

MO is quite satisfactory, however if you listen to a scene in Master and Commander in MO, you do not get as much LFE as I would like which affects the realism and oomph quite dramatically. Even at low volume level setting (-33dB on the receiver) the Hsu in ME is quite impressive in terms of the depiction of low frequency. Hence my comment about being a satisified Hsu customer wanting to experiment with the limits of the sub as I switch it over to ME for the first time.

Even under ME mode, I would not recommend adjusting the trim under maximum extension mode. You will risk clipping your subs at loud volume.

Do you a SPL meter that you can verify Audyssey's bass trim?

Yes. I have and have used it. I have set crossover higher and used Rat Shack manual meter and used the manual noise signals from the Denon. I have not gone and plotted out each frequency with test tones and made corrections to the Rat Shack meter for low frequency, though.

Since Audyssey tend to calibrate for a "flat" frequency response, I would stick with MO mode and increase your trim 2-3 dB. Try it and see.

I have tried small adjustments to trim. For music I prefer the flat response. For home movie, I have not in 2 years made up my mind on that one, but I have listened with MO bumped up enough to have a good sense how it has changed the sound when I start listening to ME and trying to decide if it sounds okay.

If you're not satisfactory, try using the VTF3.3 nearfield.

Near field is not an option due to (1) the odd listening layout and (2) because it is a multifunction room with a significant collection of south-east asian art and antiques on display. 2nd sub is also not an option right now. Again, I am not trying to get more output after 2 years of use, just want to experiment with the other thing this sub is designed to do to identify whether the port noise is a concern at reasonable volumes in the large space or not. Clipping is not from my experience with Max Extension mode much of a concern. The speaker and sub can play fine at much higher volumes (I have actually set up a limiter on the Denon at 0dB which is already deafeningly loud from most sources).

If Turbo was still available I would probably just buy that if reasonably priced. However, in it's absense I want to test ME and make decision what mode to keep it in.

[skool]

Wow, thanks for the detailed reply.

How's your experience so far with ME mode in your room? Under ME mode, I would calibrate 2-3 dB hot. Watch some movies such as Transformers 2 at higher volume, if you're hearing some port noises, then I would go back to MO mode. If not, you're better in ME mode.

[tman]

Listened to 2nd half of Incredibles tonight. Had to dial down from -10 to -15 to -18dB due to complaints for loudness. THe THere is definately a variation in the LFE within the space but I think the whole room is happier with ME so far. The ornithopers flying by sound way more impressive in ME. Frankly I think 2 subs would be best in this space, but I'll probably wait til the kids are in high school and buy a $550 DIY kit.

Will re-watch Gladiator on Blu Ray this weekend and try some of the test disks mentioned.

[skool]

I am glad to hear you're happy with ME mode. I tried MO mode in my room, which is much smaller than yours, didn't notice much more output versus ME mode. However, it is likely due to the fact I watch movies at night at lower volume. One thing for sure though, my VTF-2 Mk. 3 blends much better musically with the mains in ME mode versus the MO mode.

For your room, although dual subs will probably be best, I would go with a larger sub if you don't have the space for two.

[tman]

Haven't had a chance to calirate yet but had a quick question.

Tried the Test disk from Hsu per your recommendations. I had a question:

On the 1st or 2nd track of the disk there is a symphony accompanying an organ. There is a sustained note in that track, which is low and sounds like it is oscilating. I just want to confirm the oscillation is what I should expect for that piece.

Regarding port noise, I'm finding the beast of a sub is creating too much LFE at low volumes so I have some rattling in my walls I will calibrate it, put a gramma under it and also play with placement to the corner, but I think I'll be pretty happy to keep the sub in Max Extension. Quite a little monster...

[Bill Mitchell]

Yes, it is the first piece on the demo disk that contains a movement of the Saint-Saens Organ Symphony. It has a sustained line that includes the lowest note on a pipe organ, at 16Hz.

My house does vibrate with this piece, as it has modal resonances at 18Hz and 11Hz. I commented on how Audyssey DynEQ aggravates this problem at below reference volumes in this thread (http://forum.hsuresearch.com/showpost.php?p=47669&postcount=25).

[shadyJ]

Yes, Saint-Saens' Organ Symphony, that track has deep and sustained 16 hertz notes, which is rare in music, so it may sound strange to you. Very few sound systems could audibly play that tune. I really enjoy that song, by the way. Another great track is 5, which is a piece from Verdi's Requim. When I first received my HB-1 speakers and VTF3, I was listening to track 4, and by the end of that track I had turned the volume way up because track 4 became very soft. Track 5 begins with a bang, and it startled not only me, but my brother who was one floor up and two rooms over!

[tman]

That's the same note I'm talking about. Quite low, quite impressive. The question I have is whether it should have oscillations (like vibrato). I don't really listen to organ music so not sure if that oscillating sound is in the source or is something to do with the sub or the room. Please advise.

[Bill Mitchell]

Yes. Think about 16Hz for a moment. At 16 cycles per second, that is slow enough that you can perceive the individual cycles. So you might think this is vibrato, even when it is staying on the same note. When I just listened to the demo disk again, the bass line is not just at 16Hz, so you will hear some changes in the note, still in the same subcontra octave.

Now you may also be hearing vibration in the house. One article I read said that in churches with 32ft organ pipes to hit this 16Hz note, they had to reinforce the structure when the organ was installed, otherwise it would shake the building apart.

[Stiletto]

At what time in the recording is the pipe organ note?

[tman]

Thanks! Don't think the room is vibrating.

Also not hearing any port noise.

I will have to post a vote for Max Extension in the poll.

[Bill Mitchell]

At what time in the recording is the pipe organ note?

In the excerpt from the Saint Saens Symphony No 3 on the BAS test disk provided by Hsu, the organ comes in at about 30 seconds. The excerpt begins with a pizzicato section, then the organ joins in playing in its bottom octave.

It could be that it's clear to me with the corner placement and with Audyssey DynEQ enabled even in MaxOutput mode, but maybe in other environments in MaxOutput mode the volume would be too low and one would need to be in MaxExtension mode to notice it. I can feel the walls shaking, the dog runs away, and lots of air is being moved through both ports.

[Stiletto]

I have ULS-15s so no Max Anything mode. I didn't notice because it is inaudible and I didn't have it turned up enough to make it felt. I cranked the sub up to +12dB on my receiver last night and was able to notice the windows shaking. Makes me want to hear a real pipe organ playing a real 16Hz note for comparison.

In the excerpt from the Saint Saens Symphony No 3 on the BAS test disk provided by Hsu, the organ comes in at about 30 seconds. The excerpt begins with a pizzicato section, then the organ joins in playing in its bottom octave.

It could be that it's clear to me with the corner placement and with Audyssey DynEQ enabled even in MaxOutput mode, but maybe in other environments in MaxOutput mode the volume would be too low and one would need to be in MaxExtension mode to notice it. I can feel the walls shaking, the dog runs away, and lots of air is being moved through both ports.