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Topic: Trying to wire my rear speakers in a new place (Read 592 times) previous topic - next topic
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Trying to wire my rear speakers in a new place

I've got to get two 6 Ohm rear speakers wired for my 5.1 system 40ft and 25ft from the receiver. Does it matter much what gauge wire I use? I have 16gauge from a previous installation in another home before we bought our current apartment. Is that overkill? What are the factors/calculations needed to figure this out? I've always wanted to properly learn about how power controls speakers.

Thanks for any help!

Re: Trying to wire my rear speakers in a new place

Reply #1 –
There are just two considerations (ignoring gold-plated deoxygenated voodoo stuff): the ability of the cable to carry the current without overheating, and the amount of power lost in the cable before it gets to the speaker.

Power = I²R, and by definition the same current flows through the wire as the speaker, so the proportion of power lost to the cable is directly proportional to the resistance of the wire relative to the resistance of the speaker.

By the same equation, you can compute the current handling requirement by taking the power specification for the amplifier (at the given speaker impedance): I = √︎(P/R).  The "gauge" of the wire is of no help here, you need to look up the current carrying limit for the actual wire.

However, there are some rules of thumb:
  • Rear speakers are never driven very hard, so the current will always be low;
  • Thick wire is never overkill if that's what you happen to have available.
It's your privilege to disagree, but that doesn't make you right and me wrong.

Re: Trying to wire my rear speakers in a new place

Reply #2 –
Quote from: tinpanalley on
Does it matter much what gauge wire I use? I have 16 gauge from a previous installation in another home before we bought our current apartment. Is that overkill?
Common commercial home speaker cable is 16 gauge, which is fine; for runs longer than 50 feet, I use 14 gauge. Good connections matter more.
Quis custodiet ipsos custodes?  ;~)