KCK: At 70 feet, you should be running 10 gauge at the minimum. Don't know the size of your amp or current draw, but the longer the run, the more voltage drop you'll have under load. Since it only costs a bit more for the 10 gauge versus the 12 gauge, use the heavier stuff right off the bat and be done with it. Even if you don't pull that much juice from the wall, you'll have peace of mind knowing that you are well covered, even for future use.
Marty: The "little" two channel Sunfire amp ( 300 @ 8 / 600 @ 4 ) can pop a 15 amp breaker if your standing on the volume with a 2 ohm load. As such, trying to drive SEVEN channels with a big amp and inefficient, low impedance speakers could be a real handful for anything less than an ideal AC circuit. Sean
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