Audio room dimensions

I have and area in my basement where I'm going to build my audio room and have a couple of options. The easiest by far is to build the room to 12'9" by about 16' perhaps a few inches less on the 16. Or, 12'9" by about 19'. The latter will require I do some serious surgery to the area at the bottom of the stairs where the door at the bottom of the basement is. My question is: will the smaller room seriously compromise the sound vs. the larger room? The finished ceiling height will be about 7'. Thanks.
The larger room will benefit greatly by allowing you more flexibility to pull your speakers farther out from the back wall if needed. If they do well with minimum distance from the back wall, the larger room allows the listener more flexibility as to distance from the speakers and getting the audio gear (most likely along a side wall) farther away from the speakers. My basement room (13.5' x 18.5') is very close to your large dimensions and that extra length beyond 16' helps a lot in the ways I described above.
I just found out about a company that could probably help you: Auralex at They offer free room analysis and recommendations (existing and unconstructed)as well as products. I'm going to give them a try. Good luck.
my stereo room is ~ 20' x 12'. I've lived in several different houses, and tried many rooms, this one is the best acoustically that I've had. You'll want that extra 3 ft so your chair doesn't need to be against the wall, and you have room to pull the speakers out into the room as Jafox says. Mine are 3 ft out from the wall, and my chair is 3 ft in from the back wall - which is what works best for me.
My room is in the basement as well and close to the dimensions you have, 14x20x7. The one thing I really really wish for (in the next house..) is a higher CEILING. While movies sound a-ok, seeing that Hollywood has no clue how to mix a soundtrack, audio feels a bit constrained. Still good, but could be a more open sound with higher ceilings.