We often get asked what size power amplifier we recommend for a particular passive (i.e., non-powered) loudspeaker model. In general, the recommendation is that you should pick an amplifier that can deliver power equal to twice the speaker’s continuous average power rating. This means that a speaker with a nominal impedance of 8 ohms and a continuous average power rating of 300 watts, for example, would require an amplifier that can produce 600 watts into an 8 ohm load.
Why is it that we recommend a power amp that’s twice as big as the speaker? The short answer is that a quality professional loudspeaker can handle transient peaks in excess of its rated power, if the amplifier can deliver those peaks without distortion. Using an amp with some extra headroom helps assure that only clean, undistorted power get to the loudspeaker.