Why a pair?

[OneMalt]

I notice from reading some recent threads that a lot of you are running 2 subs. I had always thought that the conventional wisdom was that at lower frequencies, sound was non-directional and non-imaging. What benefits are you getting out of more than one?

[US Blues]

All audible sound is directional, I had the good fortune of listening to a thunderstorm today and those low-frequency rumbles clearly emanated from specific directions. In recordings low frequency sounds- basses (acoustic or electric), drums, keys and synths- may be mixed more into one channel than the other and thus two subs will preserve accurate instrumental placement. Also, proper production of low frequencies requires lots of air movement and power, especially at realistic listening levels, and two subs will more easily provide these in spades.

These are my thoughts on the matter, ymmv.

[b3n]

Ideal theater (not home theater) uses many subs in the front and rear. Home theaters have always gained from having multiple subs to enhance the imaging and surround effects. I don't see why stereo applications wouldn't benefit from multiple subs, however in my case always using REL I've only ever used one.

[Masterlu]

I too have witnessed the fact that even the best bass from a single Gotham was directional. Adding the second one went the extra mile in providing an even greater level of realism and non-directionalilty.

JL's in particular are so musical it is much more than just "making things symmetrical" it makes the music better.

[Face]

Taken from: Harman International

Subwoofers: Optimum Number and Locations
By Todd Welti, Research Acoustician, Harman International Industries, Inc.
Intuition tells us that putting a large number of subwoofers at different locations in a room is likely to excite room modes in a more "balanced" manner, as compared to a single subwoofer. This idea has potential where there is not a single listening location, but rather a listening area. In this case, we look for consistency of acoustical response within this area. One way to approach this problem is to excite all modes evenly. Another approach is to excite as few modes as possible. Using simulations and measurements, we have made an investigation to determine whether using a large number of subwoofers is advantageous, and in particular what configurations give the best results. Several interesting and surprising results were uncovered along the way.

To read the white paper: http://www.harman.com/wp/pdf/multsubs.pdf

[Gonzalo]

All i can say is when I hear thinder I can't tell where it comes from unless I see a lightning first, another ; same thing about low rumble noise from earthquake, wavelength of really low bass y very large 30 40 or even 50 ft long, do you really think you cna hear where it comes from?? not really now room modes and reflections will interfere with teh rest of your music and also that is true . . .
Just experiment with location and your tastes listen and you'll see , ,,

Take care;

Gonzalo

[Charles]

IMO low bass can be directional. If you place the subwoofer way over in a corner to the left or right you may notice directionality. I employ a Krell MRS subwoofer which is the best subwoofer in the world. It is not so much the quantity of the bass but the quality of the bass and the quality of the electronics that separates it from other subwoofers. Any signal that passes through a subwoofer crossover and then to a high resolution highend 2 channel audio system is colored and degraded audibly by a subwoofer crossover. The Krell MRS has associated electronics that are truely highend so signal degradation is minimal. Mine sets in between and slightly behind my McIntosh XRT 29's. It is crossed over at 80 Hz, 3rd order Butterworth, slope 18 dB. My bass exhibits no directionality at all. Placement of the subwoofer is critical in a two channel system. When I bought the MRS I asked Krell about the benefits of purchasing two of them. Krell recommended against it citing the possiblity of comb filter effects. That's what Krell said, not me. I had always heard that two subs were better than one. Krell does recommend daisy chaining for increased output if it is absolutely required. The MRS has two side firing 15'' dual spider woofers, 8,000 watt power supply, class A 2,600 watt amplifier, and an all aluminium enclosure of one inch aircraft grade aluminium. The baffles are two inch thick aluminium. When the subwoofer is placed it does not move. Many subwoofers will move over time. The MRS retains absolute floor position. It's the most incredible unique piece of equipment I have ever seen. It looks like aliens built it.

Charles system
Speakers: McIntosh XRT 30's, Krell MRS Subwoofer with dedicated 20 amp line/Palladian PK10 20 amp Power Cord
Preamp: McIntosh C1000 C/P Solid State
Power Amps: McIntosh 1.2 KW's (2) each with dedicated 20 amp line, MIT Z-Cord II power cords, (2) Z-Stabilizers
Sources: McIntosh MCD11000 SACD/CD Player, McIntosh MVP881BR Audio Video Player, McIntosh MVP851 DVD Player, McIntosh MR85 Digital Tuner, Marantz LV510 Multi LD Player
Line Treatment Systems: MIT Z-Center, Z-ISO-Duo
Interconnects, Speaker cables & Power cords: Kimber Kable Select Copper top tier both balanced and unbalanced interconnects are employed throughout, Audioquest Coffee USB cable for computer audio, Kimber Kable KS 3033 Select Copper Speaker Kable, Kimber Kable Palladian PK10 20 amp power cord, Multiple MIT Z-Cord II's
Computer: ASUS Laptop with Windows 7 64 bit OS and 750G HD using J Rivers Media Center, dedicated for Computer Audio

[AudioNut]

Originally Posted by OneMalt

I notice from reading some recent threads that a lot of you are running 2 subs. I had always thought that the conventional wisdom was that at lower frequencies, sound was non-directional and non-imaging. What benefits are you getting out of more than one?

Then too, it keeps your poor single sub-woofer from feeling lonely - and it helps out your dealer a lot too.

[Face]

Originally Posted by Charles

When I bought the MRS I asked Krell about the benefits of purchasing two of them. Krell recommended against it citing the possiblity of comb filter effects. That's what Krell said, not me. I had always heard that two subs were better than one.

When set up correctly, two will have flatter room response than one. The possibility of comb filtering is possible if the person setting them up doesn't know what they're doing(incorrectly setting phase, etc...). I'm surprised they don't have some sort of room correction or DSP circuitry, even the lowly JL Audio Fathom and JL in wall's come with room optimization.

[drummermitchell]

I'd borrow or home audition from your dealer another sub(preferably the same as what you have).
Instantly you'll here the balance of bottom end,nice layer of bottomend for the rest of the music to play on.
I use to use one and then added another,SHOWTIME.
The audition's free and then YOU will know.