Amplifier Specs

Question is different from accusing somebody of cheating.

B&K amp in question is most likely class D amp where output circuitry (Zobel network) would burned out at full power at high frequencies. It is irrelevant since there is very little power in music at these frequencies but there is no easy way to specify it (it's a curve). It might apply as well to class AB amps since most of them has inductor on the output.

Most of manufacturer's don't even specify frequency range for the power. Not only class D (Rowland, Bel Canto and most likely hundred of others) but also other classes amps (Krell for instance) don't have frequency specification for the power at all. Are they all accused of cheating as well?

Do not call it cheating unless you can explain why you need 150W above 1kHz.

Mordenmail - I don't think 20Hz-20kHz is "given" since full power at 20kHz is absolutely useless. For class D it could not be possibly specified for the reason I mentioned before (full power at 20kHz would damage output filter).

Average music power is only few percent of max power. No need to design class AB amplifiers for sustained max power - otherwise they would have same size heatsinks as class A amps. Maximum current available is what counts.