Dual Subwoofer Question

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wydileie

Audiophyte
#1
I am sure this has been asked a million times, but I couldn't find a definitive answer, so I am looking for input.

I recently purchased a HSU VTF-15H MK2. Previously I was running dual Energy 10" (S10.3) subs. I have my HSU tuned to the 16 Hz mode (at least I believe I do). The Energy subs are rated for 21Hz, but most people place it closer to around 26Hz before a substantial dip. If I continue to run dual subs with my HSU and one of these Energy subs, will I be hindering my low bass performance (14-26Hz levels)?

Basically, I'm asking if I should just run solo with my HSU, or run dual with one of my Energy subs. I am currently running dual because I thought it would help bolster the mid bass, but I feel like I can't really feel the low bass resonating as much as I hoped, or expected.
 
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shadyJ

Audioholic Spartan
Ratings
3,261 28 15
#2
The Energy subs probably can't contribute much alongside a VTF15h mk2. One problem they may present is that the phase of the output of any ported sub goes bananas below its tuning point, so the Energy subs may be causing some cancellation below their tuning point, meaning you may get less deep bass than simply running the VTF15h mk2 alone. More than that, if they are not heavily limited below their tuning, they will be distorting a lot versus a VTF15h mk2 below the tuning point, meaning all they will be contributing is distortion rather than clean bass. When you mix different ported subs in a system, you want their tuning points to be roughly similar.

Do you have a way of taking measurements of the output of each of the subs in your setup like with Room Equalization Wizard?
 
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wydileie

Audiophyte
#3
Thanks, that is kind of what I figured after I felt the lack of deep base out of the HSU. Although, my room is definitely nowhere near good for bass either, so that may be a contributing factor.

I don't have the equipment necessary for a good measuring. Also, I'm not sure it could help me much besides just removing the Energy sub. Due to the wife, I only have two places I can place subs (both corners of the room, luckily),so I can't do a crawl or anything.

I assume I will need to re-run my Audyssey setup after removing the Energy sub?
 
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shadyJ

Audioholic Spartan
Ratings
3,261 28 15
#4
Thanks, that is kind of what I figured after I felt the lack of deep base out of the HSU. Although, my room is definitely nowhere near good for bass either, so that may be a contributing factor.

I don't have the equipment necessary for a good measuring. Also, I'm not sure it could help me much besides just removing the Energy sub. Due to the wife, I only have two places I can place subs (both corners of the room, luckily),so I can't do a crawl or anything.

I assume I will need to re-run my Audyssey setup after removing the Energy sub?
Yes, you will need to rerun Audyssey.

To get the most deep bass from the VTF15h mk2, make sure it is set to '1EQ' with one of the ports plugged, and set the Q control to '0.7'. However, the lack of deep bass could be a room problem, or maybe a problem of what your expectations might be for deep bass. We would need to see in-room measurements to be sure.

Make sure it is not your expectations that is the cause. A lot of people think that 20 Hz bass and lower should be some kind of monstrous earth-quacking sensation, but in reality it is a subtle effect unless it is experienced at insane SPLs (your wife would not accommodate the kind of system that could achieve this). The VTF15h mk2 itself does boast a flat response down to 16 Hz, so the deep bass should be there unless your room acoustics are causing nulls at your listening position.
 
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wydileie

Audiophyte
#5
That's fair. Thanks for the feedback. I have a pretty solid system, with a Denon AVR-X4300H, and a 5.1.4 setup comprised of midrange PSB speakers. I tend to watch some things on my own at higher levels (about -10db from reference) when the wife is not around.

It's just strange, after replacing the Energy subs with the HSU and running the Audyssey again, it just feels like I am missing the "punch" the Energy subs gave me. It does sound cleaner, but I would expect the HSU to force more air than the 2x 10" subs. I'll probably buy a mic and try to do some measuring, or maybe I should just move it to the other corner and see what it sounds like.
 
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shadyJ

Audioholic Spartan
Ratings
3,261 28 15
#6
That's fair. Thanks for the feedback. I have a pretty solid system, with a Denon AVR-X4300H, and a 5.1.4 setup comprised of midrange PSB speakers. I tend to watch some things on my own at higher levels (about -10db from reference) when the wife is not around.

It's just strange, after replacing the Energy subs with the HSU and running the Audyssey again, it just feels like I am missing the "punch" the Energy subs gave me. It does sound cleaner, but I would expect the HSU to force more air than the 2x 10" subs. I'll probably buy a mic and try to do some measuring, or maybe I should just move it to the other corner and see what it sounds like.
The 'punch' sensation is more a matter of 50 Hz to 150 Hz rather than deep bass. That occurs in the chest because the lungs act as a resonant chamber for these wavelengths, and this is why many people describe it as a 'chest-punch' sensation. What you might want to do to emphasize that range more is set the VTF15h mk2 to the '2EQ' setting, and open both ports, than set the Q control to '0.3'. After that, boost the subwoofer level in the AVR by 3 or 4 dB, or more if you desire. You might also raise the crossover frequency to 100 Hz, or maybe 120 Hz if you go with dual subs eventually. That will gain you a lot more punch.
 
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wydileie

Audiophyte
#7
So, if I got a miniDSP or something, could I use that to crossover my HSU and one of (or both) of my Energy subs, so that the Energy could handle the mid bass while the HSU handles the low range, so I can get both with the subs I already have? Or is my only real option to purchase another VTF-15H?
 
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shadyJ

Audioholic Spartan
Ratings
3,261 28 15
#8
So, if I got a miniDSP or something, could I use that to crossover my HSU and one of (or both) of my Energy subs, so that the Energy could handle the mid bass while the HSU handles the low range, so I can get both with the subs I already have? Or is my only real option to purchase another VTF-15H?
The energy subs just cant compete with the Hsu, so you definitely do not want to cross the Hsu over to them at any frequency, but you can use them to give you a bit more mid bass output. You do want to high-pass filter the S10.3s to do that though, since their deep bass would be a bottleneck on your system. A miniDSP would work as a high-pass filter, but that would be a bit of a waste of a miniDSP since it can do so much more than that. Your best bet would be to get another VTF15h mk2 and then measure and shape the response to your taste with an equalizer. You may want to sell the Energy subs to subsidize the purchase of a MiniDSP or another VTF15h.

If I were you, I would acquire a way to measure the response to see what it looks like, and that means getting a measurement mic and REW. Maybe get the UMIK mic and go from there. That will help you calibrate your entire system too, not just the bass. Once you see what you are getting, you can work from there, perhaps see what kind of addition the Energy subs can provide, and see what the response of the Hsu sub is at each of its available placements.

It is not uncommon to see large suckouts in mid bass frequencies which can make the system sound a bit anemic.

One thing you can try doing is adding the Energy subs and then adjusting the phase of the energy subs. If the phase was in conflict with the Hsu, that alone could do a lot to diminish the output of all the subs. If you add in the Energy subs, make sure that they are right next to each other or stacked on top of each other, and make sure their settings are exactly the same.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Samurai
Ratings
1,104 4 1
#10
Probably won’t add to much, but the energy’s just can’t keep pace. Even if you can figure out how to phase them, what will happen is you’ll likely drive them into distortion trying to keep up and basically hinder the overall capability of the system. I would sell them and get another HSU. Fwiw, even an spl meter can help find phase issues but it’s much more difficult than measuring with REW and a umik.
 
lovinthehd

lovinthehd

Audioholic Overlord
Ratings
3,546 16 36
#11
While you might get somewhat satisfactory results putting the Energy subs with the Hsu for now, long term getting another Hsu (or two) is the way to go.
 
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Masher59

Junior Audioholic
Ratings
15
#12
I was having that issue but with my MK2 but it was a room/placement issue. One port plugged EQ1 and Q.7. So I got another one and problem solved. I have the same X4300h with Salk LRC and Philharmonics in the back. Add another one and that low end will come alive in most rooms.
 

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