Recently bought some big PA Mosfet amps off a mate of mine.

[DrNomis_44]

9kW is nothing these days. But with 2 channels per amp, that set up was probably 18kW

My small Yamaha PA system - 2 x DXR10s and a DXS12 sub was rated at around 3kW continuous and 5kW peak.

But it's the speaker efficiency that really determines the overall system loudness.

Yep, basically how many dB per Watts SPL the speaker would put-out, taking into consideration how the load-impedance varies with frequency, speaker cab resonances, and the frequency response of the speakers, you're quite right, I forgot that each of the 20 450W amps were stereo so 450W per stereo channel.


So, a speaker that has an efficiency of say 105dB/W is going to be more efficient, and sound louder, than a similarly specced speaker with an efficiency rating of say 75dB/W, because it is more efficient at converting the electrical power (energy) output of the amp into acoustic power (energy).