I used to own the Polk LSI 15's but sold them and got the Polk LSIM 705's. My room is 10' by 20' and the LSIM 705's were too much bass for the room. Sold them and bought Spatial Audio M4 Triode Masters. The Spatial Audio speakers are absolutely fantastic. No bass problems and no room treatments necessary. They are 100% made in America and cost $3,000. Average 12 ohm impedance and 93db efficient. I couldn't imagine a better speaker for classical music (or any music for that matter) than these speakers in the room size that I have. I don't listen to much classical music but when I do, the soundstage is so large and the imaging so precise, it feels like I am in the audience.
Disclaimer: I have them powered with a CODA 10.5R amp that puts out 100 watts (25 watts Class A) and an Audible Illusions preamp. I don't know if the 20 watt Decware amp could bring them to life or not because even though these speakers are high impedance and are fairly efficient, they are open baffles. I tried a Cary Rocket 88 tube amp with them and was not satisfied with the bass so I got the solid state CODA amp. I do not feel a need for a subwoofer using the CODA amp..