Re: Different speaker wire lengths


<vinylanach@xxxxxxx> wrote in message
news:c6f8ef5e-5402-450d-938f-5b16ef913c9f@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Mar 7, 8:16?pm, dizzy <di...@xxxxxxxxxxxxxx> wrote:
vinylan...@xxxxxxx wrote:
On Mar 7, 3:00?pm, dizzy <di...@xxxxxxxxxxxxxx> wrote:
vinylan...@xxxxxxx wrote:
Don't "fold it," exactly. Bend radius is very important with cabling
of any kind to avoid a degradation in the signal. ?The general rule of
thumb is to keep the bend radius more than 4 times the width of the
cable jacket. ?So if your cable is 1/2" thick, keep the bend radius
greater than 2". ?Failing to do this will increase near end crosstalk
and attenuation as well.

Where can I get some of what you've been smoking?

I was a telecommunications technician for 8 years. ?I've been
certified with Belden and Wirescope. ?I've tested and measured
thousands of miles of cable. ?I've led training classes on cable
testing. ?And what are your qualifications?

I'm a EE, and apparently not as high as you are at the moment.

Oh yeah...you fix bicycles in the Ozarks. ?LOL!

Come on - share some of that stash.

:If you're an EE, why the bike shop in White Trash Heaven?

I like bikes........

Anyway, the bend radius Marc recommends is very typical
as a design rule. For example,

http://www.okonite.com/engineering/bending-ratios.html

Now the question is why? And there the discussion has
gotten a little off the path IMO.
One reason is simple, at the core of any cable is copper.
A soft metal but still a metal and if you bend it too sharply
it will crack. When you bend a rod, one side is in compression,
the other side is in tension, and if you apply too much tension
over to short a distance, it will crack. Obviously a bunch of
cracks can degrade any signal, even DC.
Stranded cable is obviously more flexible than solid as it's a bunch
of small rods but it still has it's limits.
Other cables used in higher frequency applications have to
also maintain their impedance characteristics. Coax as
an example has bend radius far greater than the inner conductor
diameter would limit because the dielectric material between
the center and outer conductors is often soft and if you compress
it by bending the cable too sharply, you will change the distance between
conductors and that will change it's impedance and degrade
a high frequency signal. This is not relevant to the low frequency
range of analog audio signals. Signal degradation of high power
speaker level signals only comes
into consideration if you're fracturing the conductors in the cable
or damaging insulation to the point of creating a short.
Cable characteristic impededance is a non-issue for audio
frequency range signals. It if was,
you'd want to match your cable size all the way to the crossover
and have impedance controlled connectors etc,
yet all speaker manufacturers recommend different gauge
wire based on the length of the run.
Cross talk is an issue that comes into play if induced by long
parallel runs before amplification, but I've never heard it on
speaker runs and my surrounds have some very long parallel
runs.

I had a mildly interesting cable experience last night. I had moved
my Orions upstairs before installing the woofers as they're getting
heavy. Anyway, I was working on the speakers dead center of
my Infinities which I only listen to occasionally while playing pool
with friends. There is no seating in the "sweet spot" but I just
happened to be there installing some drivers and
I was playing Lucinda Williams Essence (a nicely recorded CD
IMO) and I noticed the sound stage was way left. The speaker
have pots for treble and midrange and I was thinking maybe they're
set different so I pulled the speakers out to see and I realized
when I'd set 'em up to check my refoaming I'd hooked up one
side with 12 gauge (left behind from my Advents) and the other
side with 18 gauge (as the 12 gauge run for the Advents was too short).
I'd forgotten about it. I didn't have any 12 gauge left so I added
a run of 16 to the 18 and while it didn't balance out perfectly,
its a lot better.

ScottW


.

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