Should Dual Subwoofers Be Identical Models?

Discussion in 'General Audio Discussion' started by musichal, Jan 1, 2018.

  1. awillia6

    awillia6 Active Member

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    Ah, now we're getting somewhere. Do you have any ready sources that support your assertion of the localizability of sub-80Hz sound?
     
  2. JoeESP9

    JoeESP9 ESL's & tubes since 83

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    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.
     
  3. SteveA

    SteveA AK Subscriber Subscriber

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    Not got or had a sub myself but can't they be tuned to do exactly that.
     
  4. restorer-john

    restorer-john Super Member

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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.

    A full range 2 channel system incorporating subwoofers should have two identical units.
     
  5. musichal

    musichal poet emeritus Subscriber

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    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.
     
    Last edited: Jan 1, 2018
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  6. E-Stat

    E-Stat Super Member

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    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.
     
  7. restorer-john

    restorer-john Super Member

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    Surely not. E-Stat advocating for a brickwall filter? Hehe :)
     
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  8. KevinJS

    KevinJS Super Member

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    sorry. Wrong thread
     

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  9. restorer-john

    restorer-john Super Member

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    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.
     
  10. E-Stat

    E-Stat Super Member

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    Noooooo! Just observing their nature.

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

    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.

    [​IMG]

    Now, they eliminate stator slap with the stats.

    [​IMG]

    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.
     
    Last edited: Jan 1, 2018
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  11. awillia6

    awillia6 Active Member

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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...
     
  12. musichal

    musichal poet emeritus Subscriber

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    Many people have difficulty getting the concept of roll-off slopes, is my opinion. Either that, or they think the effects negligible, and ignore.
     
    Last edited: Jan 13, 2018 at 4:01 PM
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  13. awillia6

    awillia6 Active Member

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    I LOVE it! Let 'em roll off the bass and forget the whole thing. 'Nother round over here for me and my friend.
     
  14. musichal

    musichal poet emeritus Subscriber

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    I would correct that to "many people's subjective experience..." and etc.
     
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  15. pch300

    pch300 Member

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    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.
     
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  16. JoeESP9

    JoeESP9 ESL's & tubes since 83

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    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.
     
  17. awillia6

    awillia6 Active Member

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    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?
     
  18. biscuithead

    biscuithead Me likes the eargasm retroplasm... Subscriber

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    I've done both... and to my surprise, it does matter. The single channel bass. I now have two subs, one for my left channel, one for my right channel. I have started listening to a lot of Yo-Yo Ma... you can certainly hear a difference.
     
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  19. soundmig

    soundmig AK Subscriber Subscriber

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    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.
     
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  20. musichal

    musichal poet emeritus Subscriber

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    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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