Well I used the Google translator to check out the Japanese page of the XR55. It was pretty tough to translate what the translator was saying, but there was one really interesting tid-bit:
"With new development "dual amplifier" the ハイクオリティ(High Quality) the stereo re-to raise, furthermore with bi- wiring connection treble quality actualization. Even with the speaker of bi- wiring connection non- correspondence it drives with two amplifiers. By the fact that the speaker is driven in ability of former 2 times, clearing which has the transparent impression medium high pass and the force which has tightening bass is actualized heavily. Furthermore when the bi- wiring you connect, treble quality it can enjoy stereo playback by the fact that 2 speakers are driven with six amplifiers."
http://panasonic.co.jp/corp/news/official.data/data.dir/jn050406-6/jn050406-6.htmlI think what this says is this:
1. If your speaker isn't bi-wirable, 2 amps can be used to drive it. . .possibly via bridging.
2. If your speaker is bi-wirable, you can use 6 amp channels to drive it, 4 for the lows and 2 for the highs.
Hope it doen't use the relays in the 70, but splits the digital signal instead to feee a duplicate signal to all channels. Much better than Party Mode.