Glen, even for the highest audio frequencies RG59(or even smaller coax)would be good for over a hundred feet. The cable to a sub has probably the easiest job in all of audio since it is just responsible for analog signals from about 20-100Hz. The usual precaution to not run it near power lines for a significant distance should be taken, but the ordinary well-shielded coax will rarely run into a problem with interference.


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Enjoy the music, not the equipment.