Power Cord Burn-In

A couple of humorously wrong remarks from the good Dr. Greenman. BTW, my Ph.D. is in an area of physics and also from an ivy league school, but like other Ph.D's, I don't advertise it.

"Just as pilots have to learn to ignore their fallible
senses and trust their instrumentation - or they end up
like JFK Jr; you have to realize that your ears are not
the fine tuned instrumentation you think they are."

I worked for many years in defense systems, specifically on the radar systems used by fighter pilots. As to sensory phenomena, pilots use radar to detect objects coming at them, meaning missiles and other aircraft. A fighter pilot looking at a screen can detect the presence of a target (signal in a noise background) much sooner than any automated algorithm we've ever known how to write. This is an extremely well-recognized issue called "man in the loop". The reasons why trained human beings are better at detection than instrumented detectors is that in the instrumented system, the designer uses linear statistics. A trained human, on the other hand, uses non-linear, and sometimes highly biased statistics based on past experience, on assessments of his situation, and on a lot of experience in dog fights. A commercial pilot will get killed by a missile when a fighter pilot will get out of the way, just exactly because the commercial pilot is inexperienced and not expecting it. But they are both looking at the same radar screen. We know how to write the mathematics of non-linear models, we just don't know how to emulate the human judgement process.

In reality, I believe there are many parallels in auditory phenomena to the visual process that I have described.

As to cable break-in, I recall that Jon Risch listed a long series of potential changes in the early hours of cable use, including burn off of plasticizers or other manufacturing residues, dielectric changes, capacitor formation.

Dear Morb,
It's also a non-sequitur to discuss the JFK Jr problem, call it "fallible senses vs instrumenation", and then use that as a proof of the limits of hearing. In fact, your comparisons are apples-oranges.

You were comparing an optical sensor (eye) with, what, EM radiation sensors(?) under conditions where the optical sensor is severely disadvantaged. Had you compared optical to optical (e.g. eye to camera, telescope) you would have discovered that the instrumentation was no better than the eye under those fogged in conditions.

My point was to say that human sensory detection uses a wide variety of criteria in arriving at conclusions, and is subject to a high degree of training (yes, pattern recognition). Agreed, it has nothing to do with electron flow, and neither does your commentary. But my point actually does have a great deal to do with why audiophiles, as well as audio professionals, become skilled in hearing fine differences, and also with a discussion on the fallibilities of double blind tests. Lets not get into blind testing here; it's a long and heated argument.

It's a necessary and good exercise to look at audio "theories" in terms of well-established scientific knowledge, like phase diagrams and electron flow. But it's also a little dangerous to always infer from the text book situation to the engineering situation; the devil is in the details, and human ears need to be trusted at times to tell you that you haven't always got the explanation right.