Small or large sub for music


I've been using a pair of Velodyne HGS-10s to supplement KEF LS50s below 50 Hz, but I read that larger subs are better for music because the cone needs excursion.  Is there any truth to this?  I have a pair of HGS-15s that I could use to supplement the LS50s or Reference 1s (below 40 Hz) if I go there.  The HGS-15s do HT superbly.

db
Ag insider logo xs@2xdbphd
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. 
Thanks for all the advice.  Whether I use 10, 12, or 15 inch subs I will use a pair, most likely placed just behind the speaker stand.  Looks good and sounds good in my experience.  The sub will be non-ported.  

I've almost decided on rosewood KEF Reference 1s.  A pair Rhythmic F12s in piano black might be a good upgrade from my aging Velodyne HGS-10s or 15s.  I might continue to use the Velodyne SMS-1 bass manager that provides acoustic room correction, although that may be redundant with the F12s.

Thanks again for helping me firm up my plan.

db
I have two Rhythmic 15 inchers. I too thought I would place them on the inside of the tower speakers. That didn't work, so I went to the printed manual and they suggested placing them on opposite ends of the room pointing towards the middle. Magic! The difference was night and day.