One sub sounds louder than the other

[matt houser]

So I have finally purchased my second sub, a matching HSU VTF-3 mk5, I have level matched them both, I have them both located at side mid-walls, I am very close to equal distance from both subs and the listening position no matter what I do One sub always seems to put out more bass than the other, it almost seems like it's mainly certain frequencies that it seems louder, it's almost like I will hear a kick drum more on one side of the room and deeper base on another side of the room, it's very strange but it almost does seem frequency related and it's not necessarily that I'm hearing the sub from a localized standpoint it's more that there is more bass at certain frequencies on one side of the room than the other, does anyone have any advice on why this could be happening

 

[tyhjaarpa]

You have different furniture / wall materials on other side? This can cause the waves to reflect differently. I have 2 matching subs as well and I have to run them at different levels to have even bass in my listening area as well.

 

[lovinthehd]

Have you tried changing the phase on one of the subs?

 

[shadyJ]

The frequencies that the sub is reproducing is supposed to be omnidirectional, ie you are not supposed to be able to determine where the sound is coming from. This is only true of 80 Hz and below. What is the crossover point in your AVR? That being said, the room absolutely is accentuating and diminishing certain frequencies from one sub to the other.

Do you have the ability to make measurements? If so, measure the response of the subwoofers individually. This will tell you how the room is affecting the response of each subwoofer.

Also make sure the subs are gain matched according to the sound pressure level at your listening position, not simply having the volume knobs at the same position on their dial. This means taking SPL readings at your listening position, and setting the sub's gain volume knobs where they generate the same SPL as measured by your listening position. You can try different test tones to achieve this, or also use a pink noise (with the mains OFF for that test).

As lovingthehd said, try different phase settings as well. Keep the phase settings that get you the most SPL. If the subs are out of phase, they could be fighting each other.

Make sure the crossover settings on the plate amp are the same. The crossover switch on both subs should be set to 'out', unless you are doing something a bit more manual with respect to bass management.

 

[William Lemmerhirt]

Do you have an spl meter? Setting multiple subs(or any really) by ear is not going to be very successful.

 

[matt houser]

I think I have come to the realization that to go any further I'm going to have to get a mic, I think I've decided to purchase the mini DSP along with it, hopefully this will expose my problems & maybe get me closer to where I need to be

 

[Bucknekked]

I think I have come to the realization that to go any further I'm going to have to get a mic, I think I've decided to purchase the mini DSP along with it, hopefully this will expose my problems & maybe get me closer to where I need to be

When I first started on the AH forum, shadyj suggested I get a better mic and do some measurements instead of relying on my ear and subjective measures. It was an excellent outcome. I bought the mini dsp microphone and did the REW measurements. Objective data means others on the AH forums could chime in with observations about the data instead of "it might be" kind of opinions. It worked out great.

Lots of help is available for how to do it and it is an interesting process. I learned a lot about my listening space. I will wager if you follow shadyj's suggestion, you will learn enough about yours to fix the lopsided low frequency stuff.

 

[matt houser]

When I first started on the AH forum, shadyj suggested I get a better mic and do some measurements instead of relying on my ear and subjective measures. It was an excellent outcome. I bought the mini dsp microphone and did the REW measurements. Objective data means others on the AH forums could chime in with observations about the data instead of "it might be" kind of opinions. It worked out great.

Lots of help is available for how to do it and it is an interesting process. I learned a lot about my listening space. I will wager if you follow shadyj's suggestion, you will learn enough about yours to fix the lopsided low frequency stuff.

Yes Believe it or not shadyj is the one who recommended the system that I now own, he also recommended a second sub which I now have, at this point why wouldn't I listen to him he's been spot on, I owe a huge thanks to him for his excellent advice, I will be purchasing a mic and mini DSP real soon

 

[lovinthehd]

Curious what avr you are using?

 

[shadyJ]

Yes Believe it or not shadyj is the one who recommended the system that I now own, he also recommended a second sub which I now have, at this point why wouldn't I listen to him he's been spot on, I owe a huge thanks to him for his excellent advice, I will be purchasing a mic and mini DSP real soon

Matt, what is the crossover frequency you are using in the AVR? How is your bass management setup in your AVR?

 

[Pogre]

Also make sure the subs are gain matched according to the sound pressure level at your listening position, not simply having the volume knobs at the same position on their dial. This means taking SPL readings at your listening position, and setting the sub's gain volume knobs where they generate the same SPL as measured by your listening position. You can try different test tones to achieve this, or also use a pink noise (with the mains OFF for that test).

This did not even occur to me. Right now I have the gains set exactly the same on both. I have an android app spl meter too. I don't know about it's accuracy, but it should work for level matching. Great tip Shady.

 

[William Lemmerhirt]

This did not even occur to me. Right now I have the gains set exactly the same on both. I have an android app spl meter too. I don't know about it's accuracy, but it should work for level matching. Great tip Shady.

Yep. Depending on placement and how hot you want to run them. You would set the first one to 73db, turn it off. Set the second one to 73db. Turn them both on and remeasure. You'll probably be around 77. Trim to taste, enjoy.

 

[shadyJ]

This did not even occur to me. Right now I have the gains set exactly the same on both. I have an android app spl meter too. I don't know about it's accuracy, but it should work for level matching. Great tip Shady.

If that is the only SPL meter you have, the way I would go about handling it is to connect the sub to a device that can playback tones, like a laptop or tablet. Use a tone generator, there are lots online like this one. With both subs having the same gain knob setting, maybe at 9 o'clock or perhaps 12 o'clock, play back a series of tones to one sub at a time, and write down the results. I would try 25, Hz, 31 Hz, 40 Hz, 50 Hz, 63 Hz, and 80 Hz. When you have the SPL values written down for each sub, lower the gain on the sub that is getting more SPL until it is in the ballpark readings of the other sub. Remember the measurements have to be made in the same exact location, so don't move your android phone once you start taking the measurements.

Another way to do it is use a pink noise like on this page. See what each sub is getting you individually with that noise, and then adjust the gain dial until they are giving you roughly the same SPL at your listening position. The pink noise is a more fluctuating sound, so you kind of have estimate the SPL it is hovering at.

 

[Pogre]

Yep. Depending on placement and how hot you want to run them. You would set the first one to 73db, turn it off. Set the second one to 73db. Turn them both on and remeasure. You'll probably be around 77. Trim to taste, enjoy.

73 db, I'm assuming you mean at reference, which is zero?

Shady, I already have a laptop hooked up to my receiver. I'm using it as a HTPC. I know it's not the best, but I had one that was only a few years old that we retired it recently. I figured it still works fine and I didn't have to go buy a new one. I have a case that folds into a stand for my tablet. I'll set it up at my seating position on something and not move it. I'm going to carefully follow your instructions on this.

 

[matt houser]

Curious what avr you are using?

I have the Denon x3100w

 

[lovinthehd]

So you can use one sub at a time and set both to the same spl level at your listening position via Audyssey....did you do that?

PS posts above from shadyj and william also leaning in this direction With two subs I'd usually try 75dB each so as to let Audyssey turn down the sub trim a bit.

 

[matt houser]

Curious what avr you are using?

Denon x3100w

 

[matt houser]

So you can use one sub at a time and set both to the same spl level at your listening position via Audyssey....did you do that?

Yes I did even try this, I am pretty sure with everything that I have tried I have gotten the gains set precisely and I continue to notice boosts at certain frequencies, unfortunately though the receiver only supports a sub woofer out with single settings, it does have two outputs but not individual outputs that you can adjust separately

 

[lovinthehd]

Probably room modes. Did you try setting phase differently yet?

 

[matt houser]

Matt, what is the crossover frequency you are using in the AVR? How is your bass management setup in your AVR?

I had spoken with you several months back about raising the crossover slightly to have more punchy midbass and I have messed around with this but I currently have the crossover at 80 Hz that's kind of where I have left it, all speakers set to small