i am wondering aboute hz ratings. most 2 channel amps have a respose up to 20000 hz. the mono class d amps that i am looking at getting generaly only respond up to 300hz. how will this affect what i hear coming out of my subs verse a 2 channel amp?
I'm assuming that you will be using the mono class D amp for a subwoofer(s). In this case, sub-bass frequencies usually fall below 100hz. Therefore, the mono amp will not affect the sound delivered to your sub. Actually, higher frequencies (over 300hz) may actually damage your sub at high volumes. Hope this helps.
class D amps are only meant for subs. subs usually play a range of 16-80Hz, so anything over about 150Hz doesn't matter (accounting for roll-off) with a subwoofer amp. multi-channel amps are class AB and mostly designed for mid/high frequency speakers like your front stage or rear fill, and not for subs. a class AB amp can run subs, but they are less efficient and high power class AB amps tend to generate a LOT of heat and draw a LOT of current, although for very high end systems, they also tend to be a bit cleaner for the really picky audiophile types.