Why dual subwoofers ?


Just got a new processor ( EAD 8000 pro ) that has outputs for two ( stereo ? ) subwoofers. What advantage is there to going with two subs ? Does it really make a difference ?
128x128robedk
It really cleaned up my bass. Now it's infinitely more accurate and, for whatever scientific principle, less boomy.
Mostly the above said is not really a good assesment of the Pro's and Con's.
Adding more subs(in this case two) can increase the obvious dyanmic range of a system, by adding more bass to the room potentially. At the very least, you can run two subs at less output than one single sub, for more dynamic potential and ease/effortlessness. That said, you can also run stereo bass(which I'm not sure your pre offers). This allows for each sub to only have to deal with Bass from the left or right channels, mixed with the LFE or .1 channel, rather than handling all the bass symultaneously.
Yes, you can smooth out potential bass mode problems by placing one sub so that it is placed to counteract bass peaks in a room, thus smoothing response overall, by not coupling well at certain frequencies, if the other sub is placed where it does excite certain frequencies. (i.e, one sub placed in a peak at say 40hz, and the other placed in the null at 40hz). When the two subs are balanced well, it evens out frequencies avaraged between the two better, rather if placed in different strategically calculated locations. Also, with STEREO BASS, you can get better potential bass separation, detail, and imaging, less distortion potentially, just like stereo woofers in a full range speaker...all to varying degrees depending on execusion, acoustics,effectiveness of set up, calibration, etc.
Basically, two subwoofers can offer a lot of advantages IF SET UP CORRECTLY! The problem here is that most would probably cause more damage than good from lack of knowledge of what they're doign if they don't implement things properly.
For instance, it's very easy to get phase cancelation from comb filtering. at certain frequencies(likely one or two different freq's), especially in "mono" dual sub configs. You can also put two subs in tandem "Peaks" at certain bass frequqencies, compounding bass modes. You can put subs at distances from each other and the wall boundaries that causes more bumps and valleys in the response as well, without getting into too many details there.(See "Haus effect/Shreoder effect", others)
Basically, I think people can't set up one sub well enough mostly, let alone two or more! But, in the right hands, dual or multiple subs can be very effective if done correctly. INfact you can do much better in the hands of a skilled person who's putting the system together. Two subs can help maximize out put, smooth response, increase range, separation, imaging, etc.
The key here is you gotta know what you're doing...otherwise, you're just adding more speakers without knowing what's happening
More is always better right?

It's either easier for placement because you have two subs to make up for any errors, or harder because you have twice the errors.

I really have not made up my mind on this one yet.....

"plus at the office you can say "I got dual subwoofers" and sound cool." YEP

Marty
Robedk, I belive that the dual subwoofer outputs on your
preamp have the same .1 signal. The second one is for use
on large rooms where one sub might not be enough. Another
reason is when one wants to use two small ones instead of one large one and blend the system with the room decor.

I use two subs on a 2 channel system, one gets the signal
from the left channel and the other from the right one.
The sound is awesome, they are big (Linn AV-5150) but the
sound (bass) did improved a lot. I started the system with one sub, didn't like it because I felt that the bass was coming from one side of the room. When I got the second one
the image came back. As stated by Themadmilkman,Slappy & Vvrinc the use of two subs will cancel some of the satnding waves and the bass will be cleaner. Hope this helps.
Well, I just ordered the second sub( another Velodyne HGS 15 ). BTW, the rest of the speakers are B&W Nautilus( 802's - mains / 803's- surrounds / HTM1 - center ). I'll let you know what I think once I get it in the system. Thanks for the feedback !