I just picked up a pair of Boston Acoustic pro60 speakers and I noticed that it says it runs at 125RMS @ 3ohms. I havent seen 3 ohm before and am not sure how to match this with an amp. The only thing that makes sense to me is to get something inbetween, like an amp that runs at like 100rms @ 4 ohm or one thats at 150rms @ 2 ohm. Anyone have an opinion on the matter? Thanks.

 

Impedance is not as cut and dry as 99.9% of people think it is. If you actually measure the impedance you will find substantial variations. I have run JL Audio amps at .66 ohms for instance, with no issues.

As for your logic on power ratings, you're about right...basically average out a 2 ohm and 4 ohm rating and you are about right.

Bottom line, an amp that has a 4 ohm RMS rating at or above your speaker's requirements will be just fine