Optimum Gauge for Networks

[blackdog]

I have been experimenting with solid core copper wires on the N500C network. Specifically, I have twisted two pieces of solid core copper wire from the network to the drivers.

I was wondering if anyone has tried this and what sort of results they have observed. I have been reading many posts on the WWW that large gauge wires cause skin effect and hence highs are lost, which means that it is preferable to use multi strand. But after my experiments, I have come to the conclusion that large gauge (16) result in a larger soundstage, thicker sound and greater details (more head count in my choir cds!)and more depth!

[Fitts]

I have built a few amps and preamps over the years, some with solid wire and some with stranded wire. The ones with solid wire always seem to be clearer and fuller sounding than the stranded wire ones.

Even though I prefer solid wire in my amps, I never thought of running solid wire to my speakers because the really heavy wire like #10 or #12 wire is so hard to work with.

What you suggest seems like a good idea. I am going to give it a try. I'll let you know how it turns out.

[[email protected]]

Any reputable manufacturer will tell you that the only thing that matters is conductivity/resistivity - that is the number of circular mils available. You can look on the WWW to find relevant discussions (ie calculations) to clearly show that though "skin effect" is a real phenomenon, it exists at megahertz frequencies, not at audio frequencies. At the bottom line, the fatter the wire the lower the added resistivity and the less effect on the system. Solid or stranded is of little importance other than the opportunity for fine stranded to corrode given its greater surface area.

[rolandr]

Guys after many years of messing with audio the story about cables is:

1) the best cable is none--keep connections as short as possible. Keep amps directly behind speakers with short speaker wire.

2)Cable should be solid core and the THINNER the better as long as RESISTANCE can be maintained as LOW as possible. Maintaining low resistance(low impedance)is particularly important in speaker cables to prevent wasting amp power heating up wires.

Why thin cable?....Electric signals travel as electric and magnetic fields. As the field tries to move inward towards the center of the wire it becomes attenuated. Skin depth is defined as the depth when signal is 8.69dB attenuated. Lower frequencies travel deeper(more skin depth) and slower than high freq (less skin depth). This difference in speed of transmission of different frequencies is large and worsens as wire is thicker and becomes longer. For example at 50 Hz velocity is 2.93 meter/sec with skin depth 9.35 mm, for 10,000Hz velocity is 41.50m/s at 0.66mm skin depth, for 20,000 velocity is 58.69m/s at 0.47mm skin depth.

So thinner wire will reduce freq time smearing whereas thicker wire either solid core or multistranded will worsen it. But you need thicker cable in speaker wires to prevent increased resistance(impedance)... Just use many thin insulated(not multistranded)wires to get the equivalent fat gauge or use flat ribbon wire.

Additionally you also have capacitance and inductance to deal with.

Shielded cables add capacitance (reduce high freq)therefore twisted pairs balanced cable is better unless in microphone use, instrument cable or high electrostatic noise areas. Do not use twisted pairs in speaker wire with high currents since the inductance created by the magnetic fields will attenuate the low freq.

Don't criticize sound reinforcement guys for using heavy gauge multistranded ZIP cable is just easy to work with. I use it myself for those purposes.

In the end don't worry to much about all this, just enjoy the music and have a brew.

Roland

[[email protected]]

Hey Roland:
Did you just say that a 50Hz signial propagates down a wire at 2.93 M/s? Isn't the speed of sound in air at sea level 344 M/s? Are you saying that a 50Hz electrical signal propagates through through a copper conductor at less than 1% of the velocity of an audible signal in air? Are you saying that a 50Hz electrical signal is slowed in its propagation down a wire from 2.99983E8 meters per second to one-hundred-millionth of that velocity as compared to a simple switch closure due to frequency? I just want to understand here.

[AllanCT]

This IS a joke... right?

[rolandr]

Guys don't crucify me yet I am only the messenger! I was also shocked when I came across this info. The point here is that low frequencies in thick cables have deeper skin depth than higher frequencies. The thicker the skin depth the slower conduction occurs. As a result IF the cable is THICK enough to allow a 50 Hz frequency to have a SKIN DEPTH of 9.35 mm the velocity of conduction would be 2.93 meters per second. Now granted that would be a very thick cable indeed. But the point is that primarily LOWER frequency time smearing (delay) increases with the increasing thickness of the cable. The figures quoted in the other above note are based on cables thick enough to allow skin depths at the level listed for the frequencies listed. In real life cables used are nowhere that thick. These examples just point out an extreme case to emphasize the point. Which again is the thicker the cable the more low frequency delay occurs because of the increasing skin depth as the frequency goes lower. The analogy used is that of a river where water flows faster on the surface than on the bottom ie: dry log on surface travels faster than waterlogged log near bottom. This led to the development of flat cables etc to diminish the skin depth low freq can go and prevent freq time smear.

Please refer to the article by Professor's Hawksford, MJ " The Essex Echo: on errors, low feedback and fuzzy distortion", HFN/RR, vol 29 number 9, page 37-41, September 1984.

Th prof gets into heavy electromagnetic theory and Maxwell equations explaining conduction in wires based on what they are... that is traveling eletromagnetic fields just guided by wires...Good luck with it.

[rolandr]

"In the end don't worry too much about this have a brew".

Cables in general are one of my last concerns in audio except as listed above. Differences may not be audibly significant at audio freqs unless you get carried away with excess lengths and therefore needed heavy gauge. Many people disagree with this view, but I certainly would not pay for fancy esoteric cables with questionable theories behind them. Nevertheless it costs nothing for home use to keep cables SHORT and use thinner multiple solid core insulated wires rather than one single fat gauge.

[airboss]

Roland:
Can you direct me to a site where this paper can be viewed? Or send me a copy? I'll gladly pick up postage etc.

It would seem that this propagation theory would be easy to test no? A signal generator, a couple of pieces of buss bar or perhaps iron rod and an oscilloscope I think. We should see some hugh (relatively) time differences between signals in the audio low and high frequencies. I think that perhaps we might even see that low frequency tones will linger in the conductor for intervals many many times there period. The first arrivals, traveling on the skin, should smear very visibly with those portions of the signal that took a deeper route. Does the paper propose that lower frequencies travel only in the interior of a conductor while higher frequencies travel closer to the surface? I suppose that what troubles many engineering types about information like this is that it flys very much in the face of conventional electromagnetic theory about velocity factor in conductors. Cables do exhibit capacitive, inductive and pure resistive values. The vector combination of these values is of course impedence. Very pronounced and audible differences can be heard in an amplifier's reaction to these impedences.....some cables do sound different with some amplifiers, but as a rule, poor cables would have to be way out there in either capacitive or inductive reactances to be audible.

My view

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We engineering types just can't accept a lot of things, like how you non-engineering types can't seem to understand that all this stuff about skin effect is about ATTENUATION not SPEED.