different length speaker cable...
 

Due to the odd location of my equipment, I would need different length runs of speaker wires for my fronts and center channel(5ft for left, 8 ft for center, and 14 ft for right). However, Im worried that this might raise problems with the sound being that the signal have much further to travel to the right speaker. Do you think this will be a problem?

The speed of light is 299,792,458 meters per second in vacuum. A cable isn't a vacuum so it's a little slower.

So no, not a problem.

I was read an engineers review of this subject and it prooved to be very interesting...essentially for you to notice any difference in cable lenght you'd have to have several miles worth of difference and not move your head an inch either way..basically its a simply not an issue to worry about. I guess it could be a factor if you were using very very small speaker cables but no one does that...even the HTiB's come with 14 guage cable.

Actually the speed of an electron (for DC) in a wire is something on the order of .000002 meters per second.

However, the speed of electrical signal propagation in a wire is on the order of 2/3 c, or about 200,000,000 meters per second.

Kinda like the speed of brake lights coming on in a traffic jam. :)

BB

Wouldn't the different length have a different capacitance, impedance or inductance?

:)ensen.

Actually it's inductance, capacitance, and resistance. (L>C>R) Again minimal impact on the 'speed' of the signal.

The standard recommendation is keep all wires the same length. That way the L>C>R impact is equalized for all the speakers.

Yes it does change the LCR...but not enough to matter...at least in conventional systems like we all run at home.

If several miles of cable will not induce an audible change, how is it Audiophiles hear a change in various materials and jackets of speaker and interconnects that are relatively short? :scratchhead:

I agree that various componets and construction techniques will have a change in LCR, however the magnitude of variance (different brands) in the typical 1-2 meter interconnect or the 3 meter speaker cable, certainly has to be less than the variance between a (same brand) meter of cable and a km of cable?

So, If a a few KM's difference of LCR doesn't not make an auditable change, how does a few meters of LCR difference make the "Hear things I have never heard before" Change?

There are two issues that are being confused here.

The reference to kilometer long speaker cables originates from the question regarding cable length and 'phase difference'. A person may ask that if their cables are a different length, will the signal arrive at the speakers at different times and cause a problem?

Well the answer to that question has already been answered, and it's no. This 'timing ' issue is not to be even considered as a problem. As stated, electricity does indeed travel near the speed of light in a wire (depending on the wires velocity factor). This speed is approximated to about a nanosecond a foot. The accepted explaination would be that if you had one speaker wire 50 feet longer than the other, then that signal would arrive about 50 nanoseconds later than the other. Well, this is about 1000 times less than human hearing can even begin to detect, so don't worry about the lengths of your cables and phase differences. If you were able to detect this 50 nanosecond phase difference, your upper hearing limit would be somewhere around 20MHz. If this were the case, you could receive most of the world’s short wave radio broadcasts directly without having to resort to a radio receiver.

The next issue as Bing offers, is the issue of mismatched lengths and the resultant impedance difference influenced by standard resistance and reactance (frequency dependant resistance caused by inductance). In a speaker cable we don't care about capacitance because it's a low impedance interface, but reactance caused by the wires inductance is important and is additive by the foot.

This impedance is indeed important, but generally not important enough to care about a few feet. The difference between a foot long cable and a 50 foot cable would have the longer cable acting as a low pass filter. That is to say, the higher frequencies would be somewhat attenuated in the long cable. They'd still arrive at the same time as the foot long cable though.....

Myself, I would make my speaker cables approximately an equal length to ensure a consistancy of sound between the two front channels. This also allows for any future changes in speaker position.

If I was in NHT's position with his (5ft for left, 8 ft for center, and 14 ft for right)....I would likely make my mains 14' and my center 8'....... 8O

brucek

The only problem I have with people making their cables the same lenght as a set rule is that it may lead some to coiling the excess cable which to the best of my knowledge would cause a bigger issue then a couple of feet difference in length in a typical system...or am i wrong on that?

Coiling the excess wire can cause a change in inductance (L) that would likely be greater than the effect you'd have by having different lengths on the mains. Besides, coiled wire is ugly, and if you use high-end cables ($$$/foot) you'd be wasting $$$.

If there is excess wire it should be 'folded' in a figure "8" configuration. That avoids creating a inductor.

Is this important thing too do? I have AR Master Series speaker wire thats precut and terminated to 15ft lengths. I'd prefer no too cut the wires if needed, yet the excess speaker wire just lies on the floor in a bundle.

ht_addict

If it's in a circle it's acting as an inductor (coil) . You should fan fold it or lay it on the floor as a figure "8"

For electrons in copper - the propagation speed is 40% of the speed of
light in a vacuum - or about 120,000,000 meters per second.

The value you give above for the electrons - is the "drift velocity".

The electrons, themselves, actually travel much faster - but they
keep stopping. It's the difference between how fast your car travels
on the highway - and your net speed for a trip if you take frequent
rest stops and stop at every McDonalds along the way.

Dr. Gregory Greenman
Physicist

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BB