Small or large sub for music

There is much more to consider than just the size of the cone. The magnet structure, the amps power, the equalizer in the sub, and then the room, placement, etc...
Rel subs are some of the best out there and they have smaller cones compared to others, Plus, Rel recommends hooking up the subs so the main speakers run full range and the Rels just add to the lower octaves to the mains.
Personally I prefer multiple smaller cones in a sub instead of just 1 larger cone, same goes for my main speakers. Instead of getting a 15” woofer, I would get multiple 8 or 10” woofers.

" Two quibbles:

1 - Room modes ARE ringing
2 - Once bass traps are in place, DSP helps with ringing and nulls. .

Not going to argue this, plenty of professional acoustics literature out there. The bass traps help de-energize the rninging, and make DSP’s possible. You can even clean up nulls this way.

The combination of sub placement, room acoustics and DSP all contribute. Well done, they are lightning fast and completely organic sounding, and bigger = better.

However, poorly done, limited placement, no bass traps, no EQ, a small sub may often sound better.

Best,

Erik"

I think we fundamentally agree, but are not quibbling past each other.  As I understand it:

1)  Treating room modes by room treatments reduces decay time (ringing).  

2)  To optimize bass in a room takes a combination of setup, room treatment, and DSP.  Just like a three legged stool, all must be applied properly to get a good outcome.  

I thave tried a ML 12 in my 17x22 room, and it was to loud for stereo music, and I found  the stereo image and depth were diminished.  So, I did not go for a sub, but try it, and I am now fixe with it.  But I would suggest to try 2 smaller sub, if you listen in stereo music.  May be it woill work with your room.  So for me, one big sub kill the magic of music.

I'm not sure whether it's a more appropriate question than your original, but it's certainly a significant factor when weigh sub-woofers for music and that is whether you purchase ported or non-ported speakers. I prefer non-ported subs as they're less boomy, faster and more natural sounding. But hey, that's just one man's opinion.

I'm firmly in the "DSP robs the music of some soul" camp (I don't trust the sonic opinions of the designers...how do they know what I want to hear?), and think a normal room (meaning with furniture, rugs, and stuff other than traps and damping panels) can sound great. If you live in a steel shipping container with no furniture you have other issues to worry about that DSP ain't gonna fix. Using 2 subs takes care of a lot of the aforementioned room mode issues if they're receiving the same signal (not stereo) at the same time...it just works. Also, if sub levels are too loud, turn it down.