Not realizing our emails would turn into public domain, I thought I would come in here and offer a response to this inquiry.
First off, we never claimed biamping would yield total output of 240wpc but instead said that the LP and HP portions of each speaker would receive 120wpc each, thus the amp had the potential of delivering a grand total of 240wpc to each main speaker. This is not the same as bridging where you would double the total power to the entire speaker load.
In reality you don’t see a 3dB gain in headroom with biamping like you would with bridging and I apologize if I caused confusion in my quick email reply. However, biamping can improve the sound quality of the system since each amp is delivering bandwidth limited amplification to their respected loads also reducing the potential of back EMF ingress from the other drivers that are now being amplified independently. Of course the true benefits of biamping cannot be realized without replacing the passive crossovers with actives, but that doesn’t mean no benefits exist for passive biamping.
In the case of a receiver amp with finite output impedance, this could be an advantage assuming the power supply is up to task for delivering full power into 4 channels instead of just two. The AVR-3805 is capable in this respect. Don’t forget that the HP portion of the speaker system usually consumes far less power than the LP portion so in a two way system the tweeter will at best consume a few watts since music above 8kHz is harmonic in nature. We have found that passive biamping of tower speakers with receivers does improve system bass control, which is likely to do more with the output impedance of the amps than actually furnishing additional power. We plan on doing more testing in the future to confirm our subjective listening assessments. Stay tuned…
