I just want to share my experience very quick. The benefit of the biwire, passive biamp and active biamp are direct proportional with the reactance of your speakers. If your speakers have near constant impedance across the frequency then you won't hear a big improvement. If your speaker cables are or very high quality wire, with very low resitance and depending on case impedance, capacitance the effect won't be so big. BUT if you have some very reactive speakers, wich fluctuating impedance then you will hear a very big impreovement in this order: biwire, passive biamp, active biamp. This is generaly valable for speakers with electrostatic panels, ribbon tweeters etc. For example I was building a small second setup with some Elac BS 203.2 with ribbon tweeters and I was planing to use a Muse 160 poweramp (160W@8ohm) and even for these small speakers rated at 60W if I remember right, I ended biamping with a B&K AV-5125 poweramp which has a simetric design and I was using two chanels per speaker. Biamping with B&K resulted in a sound far more dynamic, detalied and cleaner, the Muse was starting to roll off the high frequencies and it was loosing control on the woofer. Now trying again these configurations on a pair of Rogers LS7t the difference was not so big. I found this article interesting: Link removed by moderator.