Room size.


I often see folks recommending speakers (or discouraging) certain speakers based on size of the listeners room.  While I have a good idea what would be considered a small room (both length and width no more than 15 ft), I am uncertain on the drawing line between a medium/moderate room and a large room.  Would a 15 x 20 ft be considered medium, and 20 x 25 a large? Disregarding room height for now. 
ihor
I recommend you watch Eric Alexander's video on this subject. He agrees with me, the whole small room/small speaker thing is bogus. 

Bass frequencies are very long wavelength, so long that every room is small relative to a 50+ foot bass wave. So every room will have bass resonance problems. Big speakers with more bass output might seem to be worse, but really not, it is the room, and you can prove this as I have done by isolating the speakers on Townshend Podiums. This excites the room less and alleviates a lot of bass problems everyone will have you believe can only be handled with tube traps.

A much better approach to speaker selection is to start with number one, you do not want anything less than 92dB sensitivity. Number two, how loud do they need to play? #1 and #2 filter the field down to where you can select from what is left those that have the sound you want and the price you can afford. Size is never a factor, not in terms of sound anyway. WAF, bragging rights, different story. 
Case in point - I had a pair of Maggie 3.6R's in a small basement listening area- maybe 10'x15' -- WAY too big of a presence for that room, especially with 7' ceilings. Everything was muddy and compressed as sound waves collided everywhere. Switched them out for a pair of Triangle Celius and the sound was infinitely better even though the Maggies are, I believe, better speakers than the Celius.


As MC points out though, it also depends on the sensitivity and your listening volume.

s
15X20 is still pretty small. That is the size of my TV room. 20X25 is a nice room but still not really big. I'm a big speaker fan and I have had big speakers in small rooms and they still sound pretty good. Not a real fan of small speakers in big rooms, they can work but you might end up driving them really hard.