is there any need an active crossover in biamping a stereo system? It is said that,when we connect a act.crs.over before speaker,we should disconnect the passive crossover of the speaker. Is act.crs.over must for bi-amping? without act.crs.over cant we get the absolute resolution in the low,mid&high?. Dear friends, anyone having&experiencing with such a set up? It really works?can we hear the differences? If so, which act.crs.over(for two way speaker) is fine? & costs how much? Is there any models with DAC?