I'm currently using a Servo-15(-3db at 17hz) to augment my B&W CDM-9NT speakers(-3db at 38hz) in a room slightly larger than yours.
Surprizingly, the Subwoofer actually has slightly less apparent bass output than the speakers alone, and there is virtually zero difference in bass "impact" and "slam" with most music.
I believe this is due to a large "suckout" at 50-60hz in my room. The ideal solution would be to remove the suckout and accompanying peaks using large bass traps.
Since your room is dedicated to music, the bass traps should be much easier to implement than in a typical living room, and may even mitigate the need for a subwoofer.
Build a Better Basstrap
Surprizingly, the Subwoofer actually has slightly less apparent bass output than the speakers alone, and there is virtually zero difference in bass "impact" and "slam" with most music.
I believe this is due to a large "suckout" at 50-60hz in my room. The ideal solution would be to remove the suckout and accompanying peaks using large bass traps.
Since your room is dedicated to music, the bass traps should be much easier to implement than in a typical living room, and may even mitigate the need for a subwoofer.
Build a Better Basstrap