John Dunlavy On "Cable Nonsense"

I was using the Stereophile Test CD 3 bass decade 1/3 octave warble tones track. I agree the 2 dB hump really threw me also, since I had always believed that wire was wire and once you got a big enough one it didn't matter anymore. I was using the digital meter so under just the right circumstances it could have been a 1.1 dB difference.

There was a difference in the length of the cables, the Monster was 12 foot while the other brand was 8 foot, but I have never seen a calculated result showing that this should have made the difference in the SPL I measured. Even if it did make a difference, I would have expected this to have been consistent across the board, not varying by frequency.

Lets pretend (cause it probably will not happen in real life) that your speaker has a strong impedance dip and drops from a nominal 8 ohms to say .25 ohms. If both cables were of simular guage then the longer ones could have a little more resistance in them and not deliver the exact same current to the speaker that the shorter one did at the frequency of the impedance dip. This type of situation is where the difference could be frequency selective.

I am impressed with your testing method. Three identical measurements with test signals would imply valid results. I for one feel that the differences are very large and would like to have others see if they can find results of this magnitude. Was the test conducted while only one speaker was playing? That would help to remove some reflection problems and the effects of the other speaker. Chris

Yes those were recorded with only one speaker driven as you suggest. I should have mentioned that. I tried both methods and found that there was more than enough bleedthrough from the second speaker to skew the results so I stopped it.

Well I'm impressed by your diligence. Thank you very much for sharing your results and for taking the time and putting in the effort to do this. Here I am conjuring up all kinds of digital computer measurements, and you just go out and do the obvious test. Bravo!

Since I've heard big differences in midrange performace from cables, I can easily believe a 1db difference from cables. Frankly, from what I've experienced in the difference between the cheapest and some of the best silver cables, I'm surprised it isn't closer to 3db difference in the 3k-5khz band.

Gpalmer, you rule.

I presume the meter was FIXED on to a stand or tripod, and that the equipment was not changed in setting or other value. I think you said that you ran several iterations of the test to verify results - which would tend to verify them.

One also has to be certain of YOUR physical position at the time you take the measurements, it should be the same (of course, ideally, you wouldn't have to be close to the mic at all.

I'd like to know what the physical geometry of the cables are, both like zip cord? And what speakers and amp are you using? Do you know the impedance and phase plots for it?

The next relatively easy test to make is a gross inductance and gross capacitance check using a DVM that has these functions. Of course slicker methods would be nice, but at least you'll have a first step.

Anyhow the results you find are indicative of either major differences in C & L between these two cables, and perhaps a major interaction with the crossover components in the speakers.

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