I would think 75 watts should be more than plenty in a room that size. At least for safe listening levels. M60s are not that power hungry despite their intimidating size.

However, if you like it 'ear splitting' then proper amperage gets expensive quickly.

Edit:
Here is a calculator to estimate the amps required based on the speaker, distance and listening level. Plug in "91" for the sensitivity of the M60s.
Amp Calculator

For instance, at 6 meters, 75 watts would allow for brief peaks up to 95 db which is pretty loud. Some like it louder but you are hurting your ears.

Last edited by Murph; 10/31/13 06:47 PM.
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