Dan,

If you are running the M22's in such a small room, with that Yamaha amp, there is no way you are running out of power. If you were, you'd be deaf.

The M22's are a very transparent speaker. Any detail in a recording will come out with them.

If you are using a sub, I would recommend crossing them over at around 80hz, and send all the bass down to your sub. This will allow your Yamaha to focus more on amplifying what the M22's can really play properly, which is signal above 60hz.