# Speaker wires just as sensitive as RCAs..



## thornygravy (May 28, 2016)

I've had people tell me you should keep your speaker wires away from power wire just like your RCAs. 

I don't believe this is true. I've never had a speaker wire pick up noise from being ran next to power wire but.. maybe someone else has? What do you think?


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## gijoe (Mar 25, 2008)

Nope, speaker wires will not pick up noise like an RCA can. I've never even had trouble running RCA's next to power.


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## DC/Hertz (Nov 27, 2011)

Speaker wire is balanced so they reject noise


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## Holmz (Jul 12, 2017)

thornygravy said:


> I've had people tell me you should keep your speaker wires away from power wire just like your RCAs.
> 
> I don't believe this is true. I've never had a speaker wire pick up noise from being ran next to power wire but.. maybe someone else has? What do you think?


They will pick up the noise just as well.

The preamp RCAs are usually driven with 150-1000 ohms, and the Amp input is often 100k ohms.
If you used speaker wires there (RCA points), then they would experience the same physics as the RCAs do. The good lord does not look at the wires and change the physics in-situ.

Using the speaker wire where they belong are driven with an amp output impedance of 1-8 Ohms, and the input impedance of the speaker is in that range and the damping factor of amp is low.


So it is basically total B$ that one needs to keep them away from power lines.
But it is also true that the physics is still happening, and the amp and speaker are coupling the co-channel to ground at the speed of light plus their bandwidth.

All that presumes that there is AC on the power lines.


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## 94VG30DE (Nov 28, 2007)

OK before this gets too much further out of hand, read this: WIRE
I don't know how to put this, but ohms, don't, uhhh, "drive". Voltage drives. Speaker wire doesn't need to be kept away from power wire, but not because it's "balanced" or whatever speed of light is referring to. Speaker wire is operating at a higher voltage than RCAs. MUCH higher level means induced noise doesn't matter. 
Do high voltage wires interfere with speaker cable? - AVS Forum | Home Theater Discussions And Reviews
post #9: "The field generated by any power cable in your home is far too small to be audible in a speaker level circuit. The impedance of the speaker level circuit is the key point. There simply isn't enough radiated power coupled into the 8 Ohm speaker wire to cause even a minuscule movement of the speaker. If you doubt this try placing a unconnected headphone cable against any current carrying power cable you find in your home. Even your 30 Amp dryer cord. You will hear nothing, nada, zip. And a headphone requires much less power than a typical home speaker. It would be difficult to have any impact on even a line level coaxial run."


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## Holmz (Jul 12, 2017)

This is the key point, which I was also saying...



94VG30DE said:


> ...The impedance of the speaker level circuit is the key point. There simply isn't enough radiated power coupled into the 8 Ohm speaker wire to cause even a minuscule movement of the speaker.
> ...


But it is both the impedance of the speaker as well as the output impedance of the amplifier, that is having an effect.

The amplifier will be driving against any back-EMF that a coupled noise signal is injecting in, in a damping factor type of way.


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## gijoe (Mar 25, 2008)

High voltage speaker wire will not pick up noise.


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## SPLEclipse (Aug 17, 2012)

Holmz is correct, although jeez....I don't know of an amp with 100k input impedance.


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## Holmz (Jul 12, 2017)

SPLEclipse said:


> Holmz is correct, although jeez....I don't know of an amp with 100k input impedance.


My friends Mellios amp is 100k. And his old VTL monoblocks, that he unloaded to me, are 100k.
And Most transistor amps are 20k.

There is no standard in home audio, but maybe it is unusual for car audio to be that high?


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## Locomotive Tech (May 23, 2016)

Interestingly enough, the tranformer in my front yard exploded last week. The power company had to replace the unit......after the environmental came and dug a big hole in the yard to recover the transforme oil. The power company was here all day with the feeder lines exposed. I asked the guys if i could run a few speaker wires along the feeders when they turned the power back on and they were ok with it. 

I had time to hook up my test rig to my car and run 60' of speaker wire (nothing fancy 16 gauge copper clad aluminum), down to the xnsfmr and back up to the sub in the test rig. I set up a 40 Hz test tone, Umik and REW and when the power came back on, REW didn't measure an increase at 60 Hz? Now the spkr wire wasn't right against the feeder line (they wouldn't let me do that) but about an inch away along a 2' run. 7000 volt 60 Hz and no measurable induction?


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## thornygravy (May 28, 2016)

That's what you get for tryna cut corners with CCA wire. You're lucky you didn't die.


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## Locomotive Tech (May 23, 2016)

Really didn't cut a corner, just trying to see if a Hv transmission could induce some intereference. Not sure if anyone has pure copper lengths over 50' laying around. As far as dying......I have been working with 25Kva for over 20 years, certified "A" man and MFE, I'll be fine.


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## thornygravy (May 28, 2016)

I was just kidding man..


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## Locomotive Tech (May 23, 2016)

Should have put an emoji there, I really didn't think you were serious.


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## Jepalan (Jun 27, 2013)

Everything said so far is true, but I have seen situations where a high impedance tweeter on a passive crossover network can pick up some buzz from noisy power circuits. This is by far the exception, not the rule.


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## Fox500 (Jun 17, 2017)

thornygravy said:


> That's what you get for tryna cut corners with CCA wire. You're lucky you didn't die.


Priceless. I can see the ads now. 

Aluminum KILLS! (WHY do they do it??)


Of course, if you have 50 yr old Al wire in a house... :surprised: you're on your own!

Stevie


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## Locomotive Tech (May 23, 2016)

Jepalan said:


> Everything said so far is true, but I have seen situations where a high impedance tweeter on a passive crossover network can pick up some buzz from noisy power circuits. This is by far the exception, not the rule.


I had that once with an old set of Q216's, I was lucky though I only heard it when the power window was moving, moved x-over, problem solved.


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## Fox500 (Jun 17, 2017)

This all makes total sense, and it's great to get this perspective. The 9 million volt transformer must be a pretty clean signal. But the motor near the crossover is probably not designed to be electrically "noiseless". Why would it be? Car companies are looking at costs first. (see "Pinto, Ford, exploding, the")

But, I didn't notice anyone citing one thing, maybe because it's so obvious. The RCA signal with it's potential contamination is a low power signal which is about to be amplified to the max, noise and all. The speaker wires are carrying a lot of power which already has been amplified. In the former case, any intruding signal is going to be seriously magnified. That's probably why RCA wires are shielded coax. 

"DUH" may be the most popular response to this, so I'm handling that in advance! 

~Stevie


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