Dual VTF 15H + MBM and Audessey help please... - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 6 Old 03-26-2020, 07:42 PM - Thread Starter
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Dual VTF 15H + MBM and Audessey help please...

I just ordered a second Hsu VTF 15h MK2 today to go along with my current one that was delivered this past Tuesday. I am having a few questions setting up the subs after replacing a 3.3 with turbo.


I currently run an MBM nearfield, and the two subs will be located in the back left corner of a rectangular room 7 feet behind the main listening position. The room is 19 x 27 x 8.

My receiver is a Denon 6400h, that has two sub outputs.

Question 1.

Do I switch the phase on the subs pre audessey, or does that do it for me?


Question 2.

Do I use both sub outputs form the denon or just split the signal to both subs?


Question 3.

Can I stack the subs on top of one another?


Question 4.

Do I use dynamic eq and dynamic volume after Audessy XT32?



Question 5.

Will the duals be significantly more impactful than just one? The 15h is is clearly a beast to behold for the price tag; and is a worthy upgrade from my 3.3 with turbo; which was a revelation 12 years ago for my theater.

"Go Blue"
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post #2 of 6 Old 03-26-2020, 08:22 PM
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REW
MiniDSP 2x4 HD
Umik-1

That's the correct set of things you'll need to integrate multiple subs, especially multiple subs with radically different capabilities (MBM is a mid-bass monster), VTF-15H Mk2 are just plain monsters all around).

Q1. Don't know, don't use Audyssey myself; I'd hope it can tell you if the phase needs adjusting, but I'll have to defer to someone who uses it. Without a way to measure, you're not in the best position to judge phase. (REW & UMIK help here). However, an SPL meter and the test CD that comes with the subs will help you. The output should be 6dB higher with 2 subs. If it's not, then they're out of phase with each other (if they're both set the same and stacked, they should be in phase). When you've got them in phase with each other, then you'd use the test tones (warble would be best, IIRC), around the crossover frequency and your SPL meter to get the highest reading by flipping phase on them and seeing what it does (setting to best integrate with the main speakers).

Q2. Not sure how the MBM gets hooked up, but with just the 2 VTF's, you'd want to use one output to each VTF if they aren't stacked together. If you go MiniDSP, then you'd run everything off one output to the MiniDSP. If you run both VTF's stacked, then you should be able to use a Y splitter to them since they'll effectively be 1 sub. I don't know what audyssey will do if the MBM gets hooked to one output and the pair of subs to the other, since the MBM, to the best of my knowledge, is a 50Hz and up sub, so auddysey might screw things up when it sees a sub that does little below 30Hz and a "sub" (VTF pair acting as 1 sub) that should go down into the teens with authority.

Q3. Absolutely, you can stack the VTF's. If stacking the VTF's, you'll get about 6dB more output than a single VTF, and might as well use a Y splitter to drive them since they're effectively 1 sub when stacked from an acoustic standpoint.

Q4. personal preference.

Q5. Depends on if you can integrate them properly.

I'd recommend a MiniDSP 2x4HD, UMIK-1, and REW and then not stacking the VTF-15H Mk2 together as a general rule. However, you may have the 1 in a 100 room where the spot the VTF's are going to go results in flat bass, and if that's the case, then stack them up for more output! But you've got to be able to measure to know.

MiniDSP 2x4HD, UMIK-1, REW... The holy trinity for running multiple subs.
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post #3 of 6 Old 03-26-2020, 09:33 PM
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The VTF-15 weighs about 110 pounds. If you stack them you might dent the one on the bottom. I would place them side by side.
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post #4 of 6 Old 03-27-2020, 07:56 AM - Thread Starter
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Quote:
Originally Posted by Sorny View Post
REW
MiniDSP 2x4 HD
Umik-1

That's the correct set of things you'll need to integrate multiple subs, especially multiple subs with radically different capabilities (MBM is a mid-bass monster), VTF-15H Mk2 are just plain monsters all around).

Q1. Don't know, don't use Audyssey myself; I'd hope it can tell you if the phase needs adjusting, but I'll have to defer to someone who uses it. Without a way to measure, you're not in the best position to judge phase. (REW & UMIK help here). However, an SPL meter and the test CD that comes with the subs will help you. The output should be 6dB higher with 2 subs. If it's not, then they're out of phase with each other (if they're both set the same and stacked, they should be in phase). When you've got them in phase with each other, then you'd use the test tones (warble would be best, IIRC), around the crossover frequency and your SPL meter to get the highest reading by flipping phase on them and seeing what it does (setting to best integrate with the main speakers).

Q2. Not sure how the MBM gets hooked up, but with just the 2 VTF's, you'd want to use one output to each VTF if they aren't stacked together. If you go MiniDSP, then you'd run everything off one output to the MiniDSP. If you run both VTF's stacked, then you should be able to use a Y splitter to them since they'll effectively be 1 sub. I don't know what audyssey will do if the MBM gets hooked to one output and the pair of subs to the other, since the MBM, to the best of my knowledge, is a 50Hz and up sub, so auddysey might screw things up when it sees a sub that does little below 30Hz and a "sub" (VTF pair acting as 1 sub) that should go down into the teens with authority.

Q3. Absolutely, you can stack the VTF's. If stacking the VTF's, you'll get about 6dB more output than a single VTF, and might as well use a Y splitter to drive them since they're effectively 1 sub when stacked from an acoustic standpoint.

Q4. personal preference.

Q5. Depends on if you can integrate them properly.

I'd recommend a MiniDSP 2x4HD, UMIK-1, and REW and then not stacking the VTF-15H Mk2 together as a general rule. However, you may have the 1 in a 100 room where the spot the VTF's are going to go results in flat bass, and if that's the case, then stack them up for more output! But you've got to be able to measure to know.

Thank you for your awesome response.
If I order these parts, and am pretty tech savvy, how difficult is this to accomplish? Does it really make that big of an impact?

"Go Blue"
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post #5 of 6 Old 03-27-2020, 01:19 PM
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Quote:
Originally Posted by ccarzoo View Post
Thank you for your awesome response.
If I order these parts, and am pretty tech savvy, how difficult is this to accomplish? Does it really make that big of an impact?
If you can sign up and ask questions on AVS Forum, you can run REW and set a MiniDSP to fix the problem. All you need is a computer with HDMI output, and a few hours to monkey around.

Start looking at REW threads and you'll get up to speed quick. There are several good vids on youtube showing how to do sweeps and set EQ to fix room problems via EQ also.

It's hard to quantify what properly EQ'd bass sounds like compared to the natural response in room, as each room is different. In my case, the addition of a MiniDSP made my bass sound like it is supposed to.

MiniDSP 2x4HD, UMIK-1, REW... The holy trinity for running multiple subs.
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post #6 of 6 Old Yesterday, 09:01 AM - Thread Starter
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Quote:
Originally Posted by Sorny View Post
If you can sign up and ask questions on AVS Forum, you can run REW and set a MiniDSP to fix the problem. All you need is a computer with HDMI output, and a few hours to monkey around.

Start looking at REW threads and you'll get up to speed quick. There are several good vids on youtube showing how to do sweeps and set EQ to fix room problems via EQ also.

It's hard to quantify what properly EQ'd bass sounds like compared to the natural response in room, as each room is different. In my case, the addition of a MiniDSP made my bass sound like it is supposed to.

I just ordered the DSP and UMIK, Ihave spent thousands on the theater, a few hundred more, is a small price to pay...

"Go Blue"
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