best placement for VTF2 (original)

[Vedder323]

file:///C:/DOCUME%7E1/rbrenay/LOCALS%7E1/Temp/moz-screenshot.pngIve attached my a quick drawing of my room, im wondering the best position for 2 channel listening with my VTF2? I was thinking right in front in between my 2 speakers?

[squeeks]

Any of the empty corners would be best, generally the middle of a wall is NOT recommended

[kinggimp]

I would put it in the front right corner. You could also put it on the right side of the couch if you want more impact at your listening position. Also what would you mainly listening to?

[Vedder323]

I would put it in the front right corner. You could also put it on the right side of the couch if you want more impact at your listening position. Also what would you mainly listening to?


Mostly rock, classical, lots of acoustic stuff as well.

I might have room on the right front corner OR under the coffee table to the left of the couch... all other locations in the room are pretty much taken up.

[Vedder323]

Any of the empty corners would be best, generally the middle of a wall is NOT recommended

Thanks Squeeks, that surprises me, id think it would blend better with my 2 fronts but placing it in between them?

[kinggimp]

Thanks Squeeks, that surprises me, id think it would blend better with my 2 fronts but placing it in between them?
It is bad to put a sub in the middle of a wall because the bass tends to cancel itself out. Basically the bass travels to the corners on that wall and then travels back to the sub from both corners. When the sound from both directions meets it cancels out the sound and makes the sub sound faint. I have my subwoofer in the front corner and it blends perfectly with my main speakers. Can't even tell the bass is coming from the sub.

[Bill Mitchell]

Blending is not the issue. Provided you don't set the crossover higher than 80Hz-100Hz, you should not be able to notice the direction of the sound.

With the corner placement, the walls will help reinforce the sound from the sub, so its amp will have to do less work to achieve a given sound level. The risk with a corner placement is that it energizes the room resonances better. Although you could expect to have a resonance ~38Hz, with the large opening to the left, this may not happen as much in your room. If you set the sub up in the corner and it sounds as if the peaks are too uneven, you can try a mid-wall placement to see how it works for you. (You can use the test tones on the Hsu test disk and an SPL meter, or more sophisticated software if you are so inclined, to verify the response.)

As Andrew points out, if the sub is exactly centered on the wall, you have the risk of creating a null in the response, too.

In my case when I tried a mid-wall placement, the AVR trim/sub gain had to be set much higher for the same volume level, and there was a huge resonance peak across the room from sub to listening position that even Audyssey could not cure. So I moved the sub back to the corner.

Have fun experimenting,
Bill

[Vedder323]

Thanks guys, I bought the sub off craigslist for $80 and I dont have any kind of test cd that came with it. One of the issues im having is if I do a corner placement, ill be running tons of wire cause im using this with a tube amp which doesnt have an LFE out.

[Bill Mitchell]

Given you don't have a modern AVR with a built-in equalization system, it is even more important that you place your sub where its in-room response is smoothest. My guess is still that this will be the corner; that will give you the most extension from the room. You will have to play with the VTF's tuning to see which gives you a smoother response.

For a test disk, you could try the free one on AVS Forum (http://www.avsforum.com/avs-vb/showthread.php?t=742969). I used it as an independent verification, but I did most of my adjustment using the REW software (http://www.hometheatershack.com/roomeq/). As the receiver is not doing it for you, you will want an SPL meter to verify the level setting of the sub against one of the front speakers.

Keep in mind that the crossover built into the sub is only the low-pass-filter half of a receiver's crossover. It limits the part of the content passed to the sub, but leaves the original unchanged on the high level outputs. So you will need to be more careful where you set the crossover frequency on the sub to get it near where your front speaker response rolls off; otherwise you will hear a peak for the frequencies that are reproduced by both. This may be an advantage to you. There is no particular reason you have to feed the front speakers from the outputs of the sub; you can feed the sub in parallel with the fronts from the amplifier, or from the terminals on the front speakers themselves. This way you need only two high level cable runs, one for each channel to the sub, and not four, each channel to the sub and back again.

It would be a lot longer pair of cable runs for you, but you could try the sub in the corner next to the couch. Without an equalizer, this might give you the most even response from the room itself, sitting near field to the speaker. When I tried something like this, with the sub next to my chair in the middle of the room, I found the sound too localizable -- it annoyed me to hear cannons from Master and Commander come from beside me instead of in front of me. But it might work best for you.

Bill

[Vedder323]

There is no particular reason you have to feed the front speakers from the outputs of the sub; you can feed the sub in parallel with the fronts from the amplifier, or from the terminals on the front speakers themselves. This way you need only two high level cable runs, one for each channel to the sub, and not four, each channel to the sub and back again.

Bill, if i understand you, I can run to sets of wires off my speaker output? One to the sub high level input and one to the speakers?

PS: Doesnt that mess with ohms when you do that?

[Bill Mitchell]

Yes, exactly. You need to do that for both your stereo outputs to the separate high level inputs on the sub, because some low frequency content may be in one channel and not the other.

If you had a preamp with an LFE output and its own crossover filters, it would do this for you, combine the low level content of the two channels to send just one signal to the sub.

You can download the VTF Owner's Manual (http://www.hsuresearch.com/products/VTF.pdf), if you didn't get one with the sub. It contains some advice on how to adjust the crossover frequency when you are using high level speaker connections.

[Vedder323]

Alright, this is friggin bizarre. So... last night I tried what Bill suggested (connecting my sub and speakers in parallel (both connected from the amps speakers outputs) and the sound stage completely changed... I cant figure out what the hell is going on... its really baffling!

If I connect to the high level inputs on the sub and also use the high level outputs from the sub to my speakers, the sound stage is very confusing and not focused... it sounds over the top WIDE and the vocals are NOT centered at all.., if anything, they sound like they are all around me, and the instruments sound like they are panned extremely far left and right.

If I connect the sub and speakers both to the speaker out from my amp but dont use the subs high level "output" to my speakers, the sound-stage becomes focused and to my ears "correct". The vocals are dead center in the room the way they are supposed to be.

What the heck is going on here?

[hometheatergeek]

Make sure your speaker wire is connected correctly. + to + and - to -. Most speaker wire will usually have writing on one side of the pair of wires. Make the wire with the writing your plus side and the other your negative side.

[Bill Mitchell]

If the wiring of the high level amp output in parallel to the front speakers and the two sub high level inputs works, simplest is to go with that. Is the sub extending the low end response below what your front speakers provide? When you use the test disk, for tones below the front speakers response, you are hearing them from the sub?

Intuitively, I like the above parallel wiring system better, because you are not passing the current for the front speakers through the connectors on the sub. If you really want to play with the high level outputs, I would double check the wiring, to make sure there is no signal being passed from one channel to the other speaker's output -- that would certainly mess up the imaging.

In this thread (http://forum.hsuresearch.com/showthread.php?t=2075&highlight=high+level+output), I've found that people have problems with high level connections from certain amplifiers. In particular, there is this note (http://forum.hsuresearch.com/report.php?p=18086) on a PWM Class D amplifier. So if you describe what your tube equipment is, and what type of amplifier it is, that might lead to more suggestions. Also, do you have a tube pre-amp separate from the amp?

[Vedder323]

Hi Bill, Thanks so much for the help, I also likes the parallel wiring option but it created another problem, I have no way to filter the low end going to my mains which extend all the way down to 42hz. I liked using the subs in/out crossover cause it created a nice transition from the sub to the mains.

My system:

Source: Denon DVD-2910
http://www.audioholics.com/reviews/transports/dvd-players/denon-dvd-2910

Amplifier: Onix SP3 integrated Amplifier
http://www.audioholics.com/reviews/amplifiers/onix-melody-sp3-tube-integrated-amplifier-review

Speakers: Onix Reference 1 mkII
http://www.stereophile.com/content/av123-onix-reference-1-mkii-loudspeaker

Subwoofer: HSU VTF-2 mkI

[Bill Mitchell]

It seems you are making an assumption that is, unfortunately, incorrect. As documented in the VTF Owner's manual (http://www.hsuresearch.com/products/VTF.pdf), particularly in the table at the end, the built-in crossover in the sub is low pass only. It does not filter the bass out of the content passed on to the high level output. Using the high level outputs, you want to set the crossover in the sub low enough that it is not overlapping the front speakers, to avoid the increased level from any duplication.

If you had a separate preamp, where you could capture the low level signals, you could use Hsu's High Pass Filter (http://www.hsuresearch.com/products/high-pass-filter.html) to remove the low bass from the signals going to the amp. You would need to choose two alternate crossover frequencies at time of purchase.

I can imagine a couple of ways one could use the low-level outputs of the Denon DVD-2910 (http://usa.denon.com/DocumentMaster/US/DVD2910_ownersmanual.pdf) directly, but you would then have no volume control on the sub level output if its signal is fed before your amplifier. So those ideas probably aren't worth pursuing.

Bill

(http://usa.denon.com/DocumentMaster/US/DVD2910_ownersmanual.pdf)

[Vedder323]

It seems you are making an assumption that is, unfortunately, incorrect. As documented in the VTF Owner's manual (http://www.hsuresearch.com/products/VTF.pdf), particularly in the table at the end, the built-in crossover in the sub is low pass only. It does not filter the bass out of the content passed on to the high level output. Using the high level outputs, you want to set the crossover in the sub low enough that it is not overlapping the front speakers, to avoid the increased level from any duplication.

If you had a separate preamp, where you could capture the low level signals, you could use Hsu's High Pass Filter (http://www.hsuresearch.com/products/high-pass-filter.html) to remove the low bass from the signals going to the amp. You would need to choose two alternate crossover frequencies at time of purchase.

I can imagine a couple of ways one could use the low-level outputs of the Denon DVD-2910 (http://usa.denon.com/DocumentMaster/US/DVD2910_ownersmanual.pdf) directly, but you would then have no volume control on the sub level output if its signal is fed before your amplifier. So those ideas probably aren't worth pursuing.

Bill

(http://usa.denon.com/DocumentMaster/US/DVD2910_ownersmanual.pdf)

Bill, you are once again correct, It just now hit me that the amp doesnt have any kind of high pass filter so it really doesnt make a difference. One option I suppose I have is to sell my Denon DVD-2910 and pick up an OPPO DVD player which has a volume control... that could work?

[Bill Mitchell]

I've looked before at one Oppo player, the BDP-83. Looking at the manual (http://download.oppodigital.com/BDP83/BDP-83_English_Manual.pdf), you are right, it does appear to have its own volume control, it has an option to specify down-mixing to stereo output while specifying that the front speakers are small, so you should be able to feed its front L/R multichannel outputs to your tube amp, while passing its low-level SW output to the LFE input on the sub. The manual indicates it has a fixed crossover at 80Hz. All of which sounds as if it would work for you.

[Vedder323]

Bill, I cant even begin to thank you enough, you have been a huge help here. I think im gonna give it some time and keep playing with my settings and placement before I rush out and start swapping DVD players but it appears the OPPO is a great choice if I decided to do that.