Should Dual Subwoofers Be Identical Models?

So, if sub-60Hz is non-localizable, then the concept of "channels" does not apply to such signals, and it matters not which of any or all your subs output the sound into the listening room.

While frequencies on LP's below 100Hz are generally mixed in mono to save on groove excursion CD's have no need for it. A CD can be in stereo from 20Hz up. I've tried running my subs in mono in what's called a distributed bass system. I've even tried using just one sub. However, to my ears the sound is better running two in stereo. I can clearly hear direction when an electric bass plays an open E (41.2Hz) in one channel and not the other.
 
In that case, wouldn't it be best to break the low-end into separate frequencies which each sub would then handle on its own to reduce overall interference between competing same-frequency points sources?
Not got or had a sub myself but can't they be tuned to do exactly that.
 
So, if sub-60Hz is non-localizable, then the concept of "channels" does not apply to such signals, and it matters not which of any or all your subs output the sound into the listening room.

Of course it matters. Subs are directional. I've never heard or sold a subwoofer that can reproduce frequencies that don't betray their positions. It's a myth, especially when the content contains instruments with a range down to low frequencies where they are placed left or right in the mix.

A full range 2 channel system incorporating subwoofers should have two identical units.
 
Ah, now we're getting somewhere. Do you have any ready sources that support your assertion of the localizability of sub-80Hz sound?

Just a long history of playing test tones using my own ears, for trouble-shooting or set-up. I feel no need to read where someone noted the same thing.
 
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Of course it matters. Subs are directional. I've never heard or sold a subwoofer that can reproduce frequencies that don't betray their positions. It's a myth, especially when the content contains instruments with a range down to low frequencies where they are placed left or right in the mix.
Agree, but I think the issue is more that low pass crossovers are not brickwall in nature. Even the 12 db/octave slope of my subs (have a pair) allows audible output above 100 hz even when set to 50 hz.

In practice, I use mine to supplement the low end of smallish Acoustat 1+1 electrostats in the HT which are more comfortable not dealing with first octave content. After much experimentation and measuring the results, I get the most linear response crossing them around 80 hz where a single sub could be directional. I run the sub crossover at highest frequency and use the HT's processor for both low and high pass duty to subs and stats.
 
If your subwoofers are under/next to the speakers, the audible localisation issue would be largely resolved.

I gave up on subwoofers, even with two identical ones. I take the limitations of whatever small speakers I am using as a given.
 
Surely not. E-Stat advocating for a brickwall filter? Hehe :)
Noooooo! Just observing their nature.

Phase relationships are just as important at the bottom of the spectrum. ;)

If your subwoofers are under/next to the speakers, the audible localisation issue would be largely resolved.
When I previously used Polk LSi9 mains in the HT (to match the LSiC center and LSi7 surrrounds), I used the subs as stands. They really became powered woofers which isolated any potential bass clipping from the mains and allowed me to flatten their voice.

ht2012.jpg


Now, they eliminate stator slap with the stats.

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I agree that blending subs is not an easy task and not something I would do entirely by ear. Fortunately, the U-1s upstairs don't need them.
 
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So no agreement on localization then? I'm hearing (no pun intended) that crossover effects that allow higher than 80Hz sound to be output violate the no-localization dictum. Makes sense. I'm also hearing that either no evidence exists showing localization testing (highly doubtful considering the $$$ associated with HT and subs) or that one person's subjective experience should serve as evidence everyone is to believe (even more doubtful). The search for audio, um, truth goes on...
 
Agree, but I think the issue is more that low pass crossovers are not brickwall in nature. Even the 12 db/octave slope of my subs (have a pair) allows audible output above 100 hz even when set to 50 hz.

In practice, I use mine to supplement the low end of smallish Acoustat 1+1 electrostats in the HT which are more comfortable not dealing with first octave content. After much experimentation and measuring the results, I get the most linear response crossing them around 80 hz where a single sub could be directional. I run the sub crossover at highest frequency and use the HT's processor for both low and high pass duty to subs and stats.

Many people have difficulty getting the concept of roll-off slopes, is my opinion. Either that, or they think the effects negligible, and ignore.
 
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So no agreement on localization then? I'm hearing (no pun intended) that crossover effects that allow higher than 80Hz sound to be output violate the no-localization dictum. Makes sense. I'm also hearing that either no evidence exists showing localization testing (highly doubtful considering the $$$ associated with HT and subs) or that one person's subjective experience should serve as evidence everyone is to believe (even more doubtful). The search for audio, um, truth goes on...

I would correct that to "many people's subjective experience..." and etc.
 
Just a long history of playing test tones using my own ears, for trouble-shooting or set-up. I feel no need to read where someone noted the same thing.

I agree with JoeESP9 and musichal. I can hear a bass E (~41 Hz) and where it's coming from. I use two subwoofers. It's definitely better than one and smooths the response in the room. You have to locate each one properly to get the even bass. If you can get some that goes down to 16 Hz, that would be awesome.

Four subwoofers would be better still, and more uniform bass in the room, I've been told.
 
Agree, but I think the issue is more that low pass crossovers are not brickwall in nature. Even the 12 db/octave slope of my subs (have a pair) allows audible output above 100 hz even when set to 50 hz.

In practice, I use mine to supplement the low end of smallish Acoustat 1+1 electrostats in the HT which are more comfortable not dealing with first octave content. After much experimentation and measuring the results, I get the most linear response crossing them around 80 hz where a single sub could be directional. I run the sub crossover at highest frequency and use the HT's processor for both low and high pass duty to subs and stats.

Interesting. Before one of the interfaces self destructed I crossed my Acoustat Spectra 22's (2 panel esl like the 1+1's) at 80Hz. I moved down to 60Hz with my current Magnepan 1.7's.
 
I can hear a bass E (~41 Hz) and where it's coming from.

Assuming you're not an alien, other humans should possess the same or similar capacity to localize, what, 41Hz sound. Can they? In what numbers? Does the ability change with age, sex, experience, physical attributes?
 
My experience is that no two subwoofers placed in different spots (as they have to be if you are using two) measure the same in the room anyway. So, while it would be nice to have identical subs, I don't think it makes a huge difference. Visual aesthetics is a different matter. What makes a huge difference sound wise is having DSP to control them and get them absolutely "in-phase" with your mains and to EQ out the peaks and nulls so that they perform very similarly - whether they are identical or not. As pch300 says above having more subs helps in that it smooths out the bass response in the room. I cross my subs in at 40 Hz as my mains (open baffle) are very solid down to 40.
 
I agree with JoeESP9 and musichal. I can hear a bass E (~41 Hz) and where it's coming from. I use two subwoofers. It's definitely better than one and smooths the response in the room. You have to locate each one properly to get the even bass. If you can get some that goes down to 16 Hz, that would be awesome.

Four subwoofers would be better still, and more uniform bass in the room, I've been told.

Of course, the same note from various instruments will each have it's own timbre, which include other frequencies, too. Some bass instruments might be more amenable to localization than others because of these differences in timbre, obviously. The doubter should connect two subs, turn off the main speakers and try various test tones himself. Few, if any musical instruments, emit a pure tone, although I guess synthesizers can, and may be used that way at times.

Two subs is my limit. More than that, I start to get foolish. :biggrin:
 
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