Audio Systems: Speaker Wire Guage, spatial cues, home theater receiver

Question
I am fanatic about good sound in my home-whether it's music or home theater.  I recently purchased a home and noticed that the home builder (who I'm very impressed with so far) used in-wall 16 guage speaker wire for my surround sound wiring.  They did it for free, so I can't complain.  If I'm using a home theater receiver running 140 watts per channel (8 ohm speakers), is this adequate with an average speaker wire run of 25 feet, or should I switch the wire to a lower guage?  Thanks.  

Answer
Dear Jamie,

Ordinarily I advise using 14AWG gauge wiring for in-wall installations, especially if the runs are going to exceed 25 feet. However, for surround channels, I've also found that 16AWG is sufficient so long as the runs don't go much beyond 25 feet.

Keep in mind that 5.1 channel sound is 90% front channels, 5% center channel (especially dialog reinforcement), and the last 5% spread between (and in the case of 7.1 applications among) the surround speakers. Since surround sound is intended to provide ambience and spatial cues, I don't believe the wire gauge is as critical as it is for the front and center channels. So, 16AWG for a 25' run should do the job. However, if you're going to go much over that, say 30' or more, I wouldn't chance a voltage drop affecting the sound and would opt for 14AWG.

I just prewired a new family room. The surround runs are no more than 25', but I took no chances and installed 14AWG. Would 16AWG have worked? Probably, yes.

BTW, the output power of your receiver and the nominal impedance of your speakers are not critical factors. Your receiver will operate 95% of the time in the 10-15WPC range, and a nominal 8 ohms is not a difficult load. I say "nominal" because no speaker ever presents a constant load to the amplifier. The nominal rating represents an average dependent on the order of the crossover and a number of other factors.

Bottom line? You'll probably be fine with the 16AWG for the surround channels. I'd upgrade to 14AWG for the front and center channels. A good source for inexpensive and excellent in-wall wire is Home Tech at http://www.hometech.com/learn/spkrcbl.html

Good luck. And thanks for choosing allexperts.com!

Kindest regards,

Kevin