For 75-85 dB a few watts are enough so ...

Thank all your for your responses! I got it know! Macd made a good point: it has to do with the logaritmic scale. Doubling the power does not mean to doble the perceived sound presurre level just a 3 Db increse. Thanks again.

You also have to keep in mind that a low powered amp pushing a hard load can clip because of the lack of head room. You may not even know your destroying the speaker beacause of soft clipping.

Lokie,
Excellent!