Are two smaller subs better than one larger?


I have checked the threads, and many say that two subs are better than one. However, here is my question: are two smaller subs, say Martin Logan Depths, better than one larger sub, say Margin Logan Descent?

Thanks in advance, as usual,

Your brother in sonic bliss, or at least the continual search for it,

The rustler
rustler
Great replies so far, folks. I'm specifically think about adding either two Martin Logan Depths or one Descent to my Martin Logan Spires. Home theater is not involved, just pure two channel sound.
Three notes/Three caveats:

Caveat #1: Your budget is sufficient to buy 2 very high quality "small" subs - call that +/- $1500.

Note #1: A single large sub will usually provide great maximum output for a given distortion level than will two smaller subs. This observation is based on pretty extensive review of subwoofer test data.

Note #2: You can (in the vast majority of cases) achieve smoother bass response with 2 carefully placed subs (large or small) than you can with a single sub (large or small).

Caveat #2: If you're using digital room correction (e.g. Audyssey) in an AVR or Pre-Pro, you can smooth FR with the EQ.

Note #3: If you cross high enough you will need to maintain stereo integrity so 2 subs will be required.

Caveat #3: IME, few people will cross to the subs at a high enough frequency (>100ish hz) to make this concern audible (to me). Others claim that the effect is audible at a lower frequency, so this is a YMMV kind of deal.

Marty

PS If you wish to go with 2 subs for purposes of maintaining stereo integrity, make sure that your x-over will allow this. To my knowledge, very few AVRs or Pre-Pros (even those with dual sub outputs) are set up this way.
I will give this a "maybe" in response. Here is why one might be better than 2 (since the very valid reasons 2 might be better than 1 have been laid out above, in particular the emergence of stereo effects at 80Hz or so, and the potential of 2 subs to minimize room nodes):

1) The quality of the single sub is much better. I moved from dual NHT subs to a single REL Storm III, and this was definintely an improvement in my room. Related to the quality of the sub is the quality of the intergration a sub can achieve with mains. For the REL that came through their speaker level connections, but I could also imagine that single subs with DSP (digital signal processing) options could also work better than dual subs without DSP or with lower quality DSP.

2) You don't need a high crossover point. My NHT pair was originally purchsed when I needed an 80 Hz crossover point. My single REL was crossed over at 35 Hz.