Axiom Home Page Forums General Discussion Stereo Stereo amp recommendation?

Whatever the HK630 does in "small" mode is pretty good in terms of keeping the imaging, but I have no idea what that is other than knowing it uses the DSP, ie I don't know if the filter implementations are 6, 12, 24 dB/octave or whether any special type of filter was coded in the DSP.

My guess is that the HK uses 24db/octave because going through the HK crossover seems to raise the bar yet again in terms of how loudly the M2s can play "comfortably". With no high-pass they were not able to play as loud as I wanted without sounding strained -- with the PSB's 12 dB/8va they were able to play "just about as loud as I wanted" and with the HK's crossover I reach my limit before the M2s meet theirs. Crossover frequency was 80 hz in every case.

If you are OK with looking into an outboard crossover then I guess nothing needs to affect your sub purchase, ie you don't need to get any specific sub model in order to get the right high-pass filtering path built into the sub.

All I can say is that the best sound *seems* to be at the extremes... you get the best imaging (by a small margin) when the mains are getting an unfiltered signal, but you get the best SPL with a fairly sharp high-pass on the mains (matching the low-pass on the sub, of course).