Is it better to have two matched subs or one

There's a lot of unfounded info around subs, and this idea of summing bass losing info is one of them. At the 80Hz and below frequencies used for subs all bass is mono. Don't take my word for it. Hook em up yourself and listen. It simply does not matter. There is no such thing as stereo bass. Just because there's two channels doesn't mean they aren't the same. Even if they were, how would you know? We are unable to hear low bass frequencies less than a full wave. Low bass frequency wavelengths are as long or longer than the room. The sound travels clear across the room and back before we even hear it. So even if it was stereo, how would we know where its coming from? We can't. So not only is low bass not directional, we cannot hear where its coming from, and so we couldn't hear stereo bass even if it was there, which its not.

Contrary to popular belief bass can be stereo. If the bass driver from one channel is moving in the opposite direction of the other channel, when summed they can cancel out the signal between them.

@dbphd asked: "unsound/duke, how does [summing stereo bass] subtract some bass signals?"

In theory to the extent that the left and right channel bass signals are out of phase with one another, the resulting net electrical signal would be less than 100% summation. And in theory if the left and right channel bass signals are 180 degrees out-of-phase with one another, their electrical sum would be complete cancellation.

In practice, I don’t think this is a significant issue. I’ve run multiple subs in stereo and in summed mono and in dual mono and have yet to notice a difference which could be attributed to some bass signals being subtracted.

It is my understanding that true stereo south of 80 Hz or so is rare at best. 

Real (or synthetic) stereo bass can offer an enhanced sense of immersion in the acoustic space of the recording. 

Duke

Duke,

" Real (or synthetic) stereo bass can offer an enhanced sense of immersion in the acoustic space of the recording." That has been my experience and why I believe most systems benefit from using subwoofers. 

@salevick - How big is your listening room? 
Is it a dedicated room or shared living room, etc.? 
Do you have a budget in mind?