[Lex Computer & Tech Group/LCTG] speaker cables

[Paul Garmon]

On Thu, Dec 17, 2020 at 11:29 AM john rudy <jjrudy1 at comcast.net> wrote:

> I have long (maybe 15') cables from my stereo to my speakers.  In the new
> house the speakers are closer together.  Can I shorten the cables by
> folding the?. Or must I cut them to length.  Don't suggest that I move the
> speakers further away
>


Obviously, a lot of people here are versed in speaker cable technology
(both theoretical and pragmatic)!  Late to the game, but thought I would
say hello. 😉

You can shorten them, if you want, but I usually try to keep both L & R
cables roughly the same length (although for 15' you probably aren't going
to be able to hear phase differences -- and if you can hear if one is a few
nanoseconds off, maybe get a job testing audio systems? ;).  Honestly, for
short distances and low impedance cables, it mostly doesn't matter.

More importantly, I'd just make sure that wires and connectors (if any) are
clean and fit well. I once had a speaker wire that somehow
"corroded/oxidized" inside it's plastic insulation -- you could see that
because it was clear insulation -- so I tossed it out (but lamented the
loss of 50' of "perfectly good 18ga. speaker wire").  Also, if you are
using 22 ga. or other very thin "speaker wire", please don't.  Use
something like 18ga. (classic zip cord) or larger.  22 ga. may make a (bad)
difference in lack of power handling if you play louder than for mice
(e.g.1812 symphony).  Another thing is to make sure both speakers are wired
with the proper "polarity" so they are in phase
<https://www.techwalla.com/articles/what-happens-if-i-reverse-my-speaker-wires>
or you will lose most of your bass response. If you have a wire on which
you can't tell which conductor is which, use a meter, or look for some kind
of color stripe or ridge(s) on the insulation for one of the two wires. 🤔


On Thu, Dec 17, 2020 at 2:25 PM Ken Pogran <pogran at alum.mit.edu> wrote:

> Folks, I don't see how it's going to be an issue.  Speakers are low
> impedance—4 to 8 ohms, as are the amplifiers that drive them. Speaker
> signal levels are measured in volts, not millivolts.  I don't see
> how EMF-induced noise could possibly be at a level that would be the
> slightest bit audible in the speakers.  Speaker cables are typically like
> light electric cords; 18 gauge stranded. Maybe 16 (or even 14) gauge if you
> bought them at a high-end audio place. They're hardly, if  ever, shielded.
> I might worry about noise pickup in an "RCA plug" type of cable connecting
> a receiver to a powered subwoofer, where the signal level is hundreds of
> millivolts and the circuit is high impedance, but other than that, I don't
> see how noise pickup in speaker wire could be a problem.
>


The only issue might be if you had a lot of cable and stray signals are
somehow coupled back to the amplifier? More likely to happen if things are
not grounded (or badly grounded ;)?  High impedance cables are always a lot
of fun and having shielded wire
<https://www.multicable.com/resources/reference-data/signal-interference-and-cable-shielding/>
becomes much more important unless the cables are super short.


 Michael Alexander wrote on 12/17/20 2:07 PM:

> If your "cables" are truly cables (i.e., electromagnetically shielded),
> Olga's advice may apply.  My "cables" are wires; so the warnings about
> coiling might apply, depending on their orientation to the rf magnetic
> field and the radio station (where I live, my Bose radio's wire antenna and
> AC cord pick up static when on WHRB, whose signal is weak).  You're right
> to experiment.
>


For low impedance speaker wires, shielding is unnecessary, but (probably)
does no harm.  Might be more important for high impedance (e.g. microphone)
wiring though!  Since both conductors in a zip-cord like arrangement stay
parallel, they should be affected equally by stray signals, which usually
means less of an issue.


On Thursday, December 17, 2020, 1:18:45 PM EST, Olga Guttag <
guttagconsulting at gmail.com> wrote:

> This depends on the quality of your cables. The better insulated cables
> can be coiled, the very cheap ones will pick up  electromagnetic fields and
> add “noise” to your listening pleasure. If unsure try it and see what you
> can tolerate.
>


Very true for audio cables, somewhat less true for speaker wire (because as
many have mentioned, low impedance connections "don't care much").  [Never
coil broadband coax (or even bend it very sharply), because many of the
issues talked about here are much more prominent at high frequencies and
it's very hard to figure out what's wrong.]



> On Dec 17, 2020, at 11:37 AM, S Ou <shukong at gmail.com> wrote:
> https://forum.polkaudio.com/discussion/960/ok-to-loop-excess-speaker-cable
> <
> https://forum.polkaudio.com/discussion/960/ok-to-loop-excess-speaker-cable
> >

suggests that too much coiling might pick up other magnetic/electric fields
> (e.g. radio stations, ha ha), so "meander" them might be better. Perhaps
> the best test is just listening to your sound system and if they sound good
> with cables coiled, that is probably a less messy way to store them.  Best
> of luck!  I'd be curious to hear if you felt coiled cables caused any
> undesirable results.



I often "meander" cables when I have a mess of them connected to a computer
-- USB, power, Ethernet, whatever.  So as not to couple them all
together, although I have no idea if it's ever really affected things.

I did once have a customer who complained that at a 48,000Hz audio sampling
rate (digital audio), the left and right output channels were 1/2 sample
off when sourced from a mono signal! Not sure anyone could hear something
like that, but they could clearly see it on an oscilloscope and were
apparently sticklers for perfection, since they were a production company.


Glad to see a lot of fun discussion on what seems to be a simple topic, yet
has quite a bit of depth!


Paul
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