Rick, keep in mind that each amp channel is driving its own speaker and it doesn't know about the others. Each channel uses the amount of power from the amplifier's power supply section that it needs for its own speaker. As long as the total power that's needed in all channels for their requirements at the moment(some very little)is supplied everything's fine. Differences in impedance among the speakers aren't a problem.

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Enjoy the music, not the equipment.