I read this article then I needed to understand the issue.
http://www.ultimateavmag.com/avreceivers/605arcam/index1.html
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On the Arcam, however, a menu option allows the two extra amp channels to serve your main L/R speakers in bi-amp mode. In my system, the result was a dramatic improvement in overall sound quality with both stereo and multichannel sources. (Speakers with bi-amp capability have separate pairs of input terminals for the high and low frequencies, which are normally jumpered together. In a bi-amp situation, the jumper is removed and each speaker is fed a full-range signal from two separate amp channels via two separate speaker wires, one connected to the speaker's HF terminals and the other to its LF terminals. Most high-quality full range speakers are bi-amp compatible.) "The text was taken from the article writen by Lawrence E. Ullman, June, 2005 at UltimateAV.com"
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