When 12 Gauge Wire is not 12 Gauge!

[amirm]

Would using AC change your measurements, given that it's AC-current from amplifier to speakers, and not DC? (Just for my edification).

DC resistance affects all frequencies equally. AC however changes based on frequency so there is no one single number there.

And while I would never attempt to use coat-hangers myself, I do remember that gizmodo-article, and that they twisted and soldered four coat hangers to create a speaker cable. Maybe they realized they would need more than one.

This is the mother of all fish stories. This was reported on countless web sites, blogs and some online rags such as Gizmodo as if it was some thorough analysis. It was not. It was a casual test reported by a "Dr. Bob" in this forum post: http://forums.audioholics.com/forum...ers;-when-good-enough-enough-3.html#post15412

Go to next page of that thread and you see him saying he is a (medical) doctor and that it was his brother who was an engineer and created the coat hanger speaker wires. That is the sum total. From this one anecdotal post, the thing grew into fact: "coat hanger beats monster cable." I challenge folks to try to make a speaker wire out of coat hangers that can be plugged in and out quickly in a blind test. Not saying it can't be done but it is hard. For one thing, if the coat hanger is conductive -- and not all are -- how do you get a pair that doesn't short out as the two wires cross when you move them? Soldering will be a total pain too as this stuff is not made to accept solder. And they are stiff as heck.

Again, this could be done but the proof that it was done and was done properly takes a lot more than hearsay in a forum post. Everyone wants to believe its message so it has become "fact."

 

[RBFC]

My wife really likes my new speaker wires because my closet is more organized than ever before. I put in a 7.1 system and it holds all my shirts neatly as well!

Lee

 

[Johnny Vinyl]

my wife really likes my new speaker wires because my closet is more organized than ever before. I put in a 7.1 system and it holds all my shirts neatly as well!

lee

lol!

 

[Empirical Audio]

Inductance of the wire is just as important as resistance, maybe even more important. Low inductance is what enables HF transient currents to be delivered to the speakers at the same levels as steady-state low frequencies.

I performed a series of measurements and computer simulations using expensive modeling software when I was still designing cables. My measurements show that 6 feet of stranded copper speaker wire has the same inductance as 30-feet of ROMEX.

The data also shows that the inductance of a properly designed speaker cable with optimum geometry using a multitude of smaller conductors will have 1/10 of the inductance of ROMEX or two-conductor cable, given the same cross-section gauge.

If you must use stranded copper, at least get silver plated strands so that the oxidation on the copper does not interfere with the performance.

Steve N.
Empirical Audio

 

[cjf]

Inductance of the wire is just as important as resistance, maybe even more important. Low inductance is what enables HF transient currents to be delivered to the speakers at the same levels as steady-state low frequencies.

I performed a series of measurements and computer simulations using expensive modeling software when I was still designing cables. My measurements show that 6 feet of stranded copper speaker wire has the same inductance as 30-feet of ROMEX.

The data also shows that the inductance of a properly designed speaker cable with optimum geometry using a multitude of smaller conductors will have 1/10 of the inductance of ROMEX or two-conductor cable, given the same cross-section gauge.

If you must use stranded copper, at least get silver plated strands so that the oxidation on the copper does not interfere with the performance.

Steve N.
Empirical Audio

I wonder......how long do you suspect it takes for jacketed Copper wire to oxidize enough to effect performance assuming its not run in an environment with high levels of humidity or under water?

I've always though Silver plated wire sounds like poo (Harsh) but then again, maybe it was some other outside variable causing this to happen?

 

[Speedskater]

Measuring the inductance of a single wire is of little concern, what is of interest is the loop inductance of a loudspeaker cable. That would be measured with the Hot & Cold conductors jumpered at the far end. With the lengths being equal, the cable having the wider conductor spacing will have the higher loop inductance. (over simplified)

* * * * * * * * * *
The longer the speaker cable and the lower the high frequency impedance of the loudspeaker, the more interesting loop inductance will be.

 

[Empirical Audio]

I wonder......how long do you suspect it takes for jacketed Copper wire to oxidize enough to effect performance assuming its not run in an environment with high levels of humidity or under water?

I've always though Silver plated wire sounds like poo (Harsh) but then again, maybe it was some other outside variable causing this to happen?

Most copper off the spool used to build cables is already quite oxidized. Just strip some copper wire from Home Depot and hit it with steel wool to see what I mean.

I don't care much for silver plated, except for speaker cables, where it is excellent. Not as good as pure silver of course.

As for pure Silver, there is good silver and poorly handled silver. You must start with very good purity and large crystals, like OCC silver. Then you must anneal it properly and then take great care in assembly not to break the crystal lattice. If you do all of these, then there is no harshness to silver.

Steve N.
Empirical Audio

 

[Empirical Audio]

Measuring the inductance of a single wire is of little concern, what is of interest is the loop inductance of a loudspeaker cable. That would be measured with the Hot & Cold conductors jumpered at the far end. With the lengths being equal, the cable having the wider conductor spacing will have the higher loop inductance. (over simplified)

* * * * * * * * * *
The longer the speaker cable and the lower the high frequency impedance of the loudspeaker, the more interesting loop inductance will be.

Measuring the whole cable is exactly what you do. I believe I used a dummy load at the end.

Steve N.
Empirical Audio

 

[Legolas]

Measuring the whole cable is exactly what you do. I believe I used a dummy load at the end.

Steve N.
Empirical Audio

Steve, what is your view on solid core silver wire for speaker cable? I am building a bi-wire pair of 12AWG solid core 99.99% silver, so 4 AWG wires to each speaker, Hard solder the cable to the silver bananas. The PTFE sheathing, and overall meshed sleeve outer.

Or do you favour 4 or 8 stander, or more strands? Seems like there is a big following in either camp. I have tried Lamp chord, 30amp mains cable, Belkin variants, Van Den Hull copper, Niam copper, Audioquest silver plated copper. I am interested to hear if my DIY cables beats these. Will get back here in a week or so with thoughts once I test them.

 

[morricab]

I wonder......how long do you suspect it takes for jacketed Copper wire to oxidize enough to effect performance assuming its not run in an environment with high levels of humidity or under water?

I've always though Silver plated wire sounds like poo (Harsh) but then again, maybe it was some other outside variable causing this to happen?

Depends on the oxygen permeation rate into the wire. If there are good seals at the terminations then it might not oxidize very quickly but if there is a leak...copper oxidizes rather quickly.

 

[morricab]

Inductance of the wire is just as important as resistance, maybe even more important. Low inductance is what enables HF transient currents to be delivered to the speakers at the same levels as steady-state low frequencies.

I performed a series of measurements and computer simulations using expensive modeling software when I was still designing cables. My measurements show that 6 feet of stranded copper speaker wire has the same inductance as 30-feet of ROMEX.

The data also shows that the inductance of a properly designed speaker cable with optimum geometry using a multitude of smaller conductors will have 1/10 of the inductance of ROMEX or two-conductor cable, given the same cross-section gauge.

If you must use stranded copper, at least get silver plated strands so that the oxidation on the copper does not interfere with the performance.

Steve N.
Empirical Audio

This is why foil, closely spaced makes good cable...it has very low inductance, although it has quite high capacitance that not all gear likes. Also, the cable from Lessloss is geometrically designed to reduce inductance (humbucking) and is using very fine, individually lacqured wire (Litz).

 

[microstrip]

This is why foil, closely spaced makes good cable...it has very low inductance, although it has quite high capacitance that not all gear likes. (...)

I owned such cables long ago - they were manufactured by Madrigal, and unfortunately in my system they did not sound any better than others. I thing it was Gary Koh who said in WBF that resistance, inductance and capacitance can't be considered separately in a cable - it is the relationships among them that matters. And surely, the voodoo parameters seem to surpass them all!

 

[DonH50]

Note silver also oxidizes to a hard tarnish arguably worse than copper. And the difference in bulk resistance is pretty much negligible (~1.59e-8 ohm-m for silver vs. ~1.68e-8 ohm-m for copper; Al is ~2.65e-8 ohm-m). Silver is also a lot harder to work with and tends to be more brittle. Once a tight connection is made, silver or copper, then that should prevent further oxidation. One reason I prefer bare wire or spades tightly screwed into plugs over the convenience of banana plugs (though there are expanding/locking banana plugs).

All cables have R, L, C, and G, and they are quasi-related (L and C are related, less so R and G to L and C), but for speaker cables R is usually most important with L a somewhat distant second for typical twin-lead construction. Special techniques like woven construction can increase C greatly whilst decreasing L but for speakers the source (power amp) is very low in impedance so worrying about RF transmission effects is silly. If you want to pursue that route, then the basic relationship is:

Z (impedance) = sqrt[(R+XL)/(G+XC)] where
R = series resistance,
XL = inductive reactance (influence of L),
G = shunt conductance, and
XC = capacitive reactance.

XL = 2*pi*f*L; XC = 1/(2*pi*f*C) where
pi = 3.141592653...,
f = frequency, and
L and C the value of inductance and capacitance (typ per unit length)

An ideal cable would have R and G zero so the cable's impedance is related only to L and C. Audio is not an RF system so transmission line equations like this are really irrelevant. What matters is the loss in amplitude and loss of damping ("control") driven mainly by the resistance of the wire (function of length and gauge). Excessive L or C can roll off highs but it would have to be really high, and high C can cause amplifiers to ring or oscillate (become unstable) again if really excessive.

Aside from a few special cables with unusual characteristics, like very high capacitance, the main issues I see (hear) are the power loss through long runs of too-small wire, and change in speaker characteristics (tone, timbre) due to the effective driving impedance being too high (again from too long a run of too small wires). If the speaker wires increase the driving impedance seen by the speaker (wire + amplifier output), then that can change the crossover slightly and affect how things like back-EMF and such from the speaker influence the sound. The amplifier has less ability to "control" the speaker.

Note tube amplifiers for the most part have relatively high output impedance and so can better tolerate higher-impedance (resistance) cables, or at least those cable affect the sound less because the amplifier's output impedance is already large compared to the cables.

FWIWFM - Don

 

[microstrip]

Note silver also oxidizes to a hard tarnish arguably worse than copper. And the difference in bulk resistance is pretty much negligible (~1.59e-8 ohm-m for silver vs. ~1.68e-8 ohm-m for copper; Al is ~2.65e-8 ohm-m). Silver is also a lot harder to work with and tends to be more brittle. Once a tight connection is made, silver or copper, then that should prevent further oxidation. One reason I prefer bare wire or spades tightly screwed into plugs over the convenience of banana plugs (though there are expanding/locking banana plugs). (...)

Copper oxide is a semiconductor and silver oxide is a good conductor - it is one of the reasons why manufacturers claim that silver plated copper is more appropriate than copper for high frequency wires. However silver tarnishing is typically silver sulfide not silver oxide, that is also a conductor but many orders of magnitude lower than pure silver. Manufacturers also claim that silver plated wires have higher corrosion resistance.

Contamination of wire is also due to chemical reactions with the insulator jacket and products due to its out gassing - colored wires are sometimes a source of problems . Van den Hul is a manufacturer that takes a lot of care with the long term stability of their wires - I have some forty year old silver plated wire that is still shining as new when I strip a bit of the insulator - it is my only experience in this very controversial subject!

IMHO the subject of wire material is complex and needs a deeper analysis. As always, IMHO and YMMV!