I also own STS's and purchased them primarily for home theatre purposes but have found them to be really good for music as well. Even though these are considered "lifestyle" speakers the same care is required in set up as any multi kilobuck "audiophile" system. I have had these speakers in two different rooms in my house (the living room at 15' x 20' and a basement room at 15' x 23') but the big difference between the two was I had to place the STS's on the long wall in the living room and the short wall in the basement room. By far the STS's prefer the short wall in the basement which allows for more space behind the speakers. The greater space was allowing for a more spacious sound stage as well as allowing me to "bump up" the bass dial a tad more than in the living room. Doing this gave the speaker more fullness which was one of my criticisms with them being in the living room.
So, to get back to your question, based on my experience only, if the room is too small I don't think you are going to get out of this speaker what it has to offer. While I don't think my living is too small for the STS's being on the long wall they were too close to the back wall (18" or so) to really let the bass response breath. It is correct that you can dial down the bass response on the back of the speakers but I think the fullness suffers in so doing, thereby accentuating the high end frequency response. In my basement music only system they are a much better speaker for music on the short wall with roughly 3'-6" to the back wall. This is all based on my relatively limited experience with this speaker in my systems.
One thing I can say for sure is one should not dismiss this speaker as just a "lifestyle" speaker meant to look good in a room versus sounding good in a room. Properly set up in a good system and friendly space this is every bit a high end speaker as anything in it's price range. Now that doesn't mean YOU will like the sound of this speaker better than any other (definitely on the detailed side of things and bass integration can be tricky) but personally I don't think it makes any compromises for the sake of good looks.
So, to get back to your question, based on my experience only, if the room is too small I don't think you are going to get out of this speaker what it has to offer. While I don't think my living is too small for the STS's being on the long wall they were too close to the back wall (18" or so) to really let the bass response breath. It is correct that you can dial down the bass response on the back of the speakers but I think the fullness suffers in so doing, thereby accentuating the high end frequency response. In my basement music only system they are a much better speaker for music on the short wall with roughly 3'-6" to the back wall. This is all based on my relatively limited experience with this speaker in my systems.
One thing I can say for sure is one should not dismiss this speaker as just a "lifestyle" speaker meant to look good in a room versus sounding good in a room. Properly set up in a good system and friendly space this is every bit a high end speaker as anything in it's price range. Now that doesn't mean YOU will like the sound of this speaker better than any other (definitely on the detailed side of things and bass integration can be tricky) but personally I don't think it makes any compromises for the sake of good looks.