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Measurement and Perception and the Value of Each (Long Post)

Posted by jrlaudio (P) on November 3, 2012 at 00:46:42

Hello All,

It's been a very long time since I have posted on AA. So after many years here we go again!

I would like to discuss the reason why measurement exists and how & why this technique has been virtually thrown away in the hi-end world.

Perception is not a purely human thing. Dogs see colors, but not like we do. Their perception is different. Dogs would (if they could) say that certain colors do not exist. Does this preclude then that in a dogs world these colors do not exist? In terms of perception they do not exist for a dog. For humans the perception is different. We see more colors.

In sound, the dog might aurally perceive an extreme high-frequency capability (above 18kHz for instance) in one loudspeaker and virtually none in another. To our perception there is no high frequency capability or even a difference at all. Our perception at those frequencies does not exist. However does this preclude that those frequencies are not present? Of course not, we simply cannot perceive them.

Human perception via senses are limited. Both in terms of degree and especially in quantification ability. Because of this academia & sciences developed empirical measurement techniques to quantify aspects of phenomenon normally observed by human perception but were difficult to quantify. As electronics developed, devices came available to measure all aspects of the specific applications being explored. Most of these devices were capable of measuring parameters far beyond the ability of human perception. This is why in the case of the "listening dog" example we can actually measure, using a device like a spectrum analyzer, what the dog is hearing and what we cannot.

The degree to which measurement can perceive differences in audio characteristics has developed to an extreme level. It can discern minute difference in most parameters and at a degree of resolution far beyond human perception.

However, it appears that human arrogance (and I do not think that is too strong of a word) has thrown aside this fact. I believe in the audiophile world many have, as a good friend of mine likes to say, "drank the Kool-aid" being served up buy those who profit from this market.

Let me give you an example. (Yes ... I'm going there). When I attended Rensselaer College and later MIT many a moon ago, we began hearing about the use of OFC copper in audio cables. We were familiar with this cable, since OFC copper cable was developed at MIT for the purpose of reducing oxidation at joints and within cable bundles for the aerospace industry (specifically for cables for the then new Boeing 747). OFC wire was designed to reduce this self-oxidation to improve reliability & safety. Nothing more. However, the application to cables for audio was never part of the original design criteria for OFC wire. Actually oxygen-free copper has been around for a long time, but using it in wire didn't become marketable or necessary until the Boeing specification was proposed.

So, as good little audio research scientists, we began to see if we could quantify the claims being made by several new audiophile cable manufacturers (who shall remain nameless). We already new that "skin effect" issues were of course non-existent at audio frequencies. It has been well documented for about 60 years that skin effect does not occur until you reach a frequency of about 65kHz. It is observable and measurable. So we knew to discount this claim as bogus. When we began taking measurements of all known measurable electrical and acoustical properties when comparing OFC to normal high purity copper we found absolutely no measurable difference. Now understand this is no measurable difference at a degree of resolution far beyond that which is perceivable by human hearing.

However, the OFC copper did not oxidize as quickly. But conversely, the oxidation on the outer surface of the wire also did not impede or effect the test measurements. It did however change things on crimped connections, particularly on micro-resistance values at the transition point of contact from wire to connector.

In our tests we measured parameters like capacitance, inductance, inherent impedances at various audio frequencies and beyond, velocity factors, damping, current handling differentials, to name just a few. We were most interested in the aspects of time differentials in relation to frequency as claimed by these manufacturers. We found that velocity factors were not effected by OFC. We also found that in these "special" cables the velocity factors for the separate windings allegedly carrying different frequencies were the same, therefore no "time correction" was actually occurring as claimed.

What we did find was significant variables in basic parameters like capacitance and inductance, within the various layers of this particular cable. In one case we measured what was in affect a RCL filter being created by the cable. It actually was producing a bandpass filter which was reducing a specific frequency and some harmonics. It was essentially, changing the response of the cable away from being flat. So here I make my point ...

Measurement allows us to learn the truth, in quantifiable terms about what we can and cannot perceive. However, perception and taste can at times be at odds with this. Why? It's a matter of what one wants.

A person may want a sound system that reproduces with the greatest accuracy what is on the source material. Others may prefer to deviate from this to produce an aural aesthetic suited to their taste. A "warm tubey sound" for instance. And you know what ... That's OK.

However, let me give you a lesson in what thinking is going on the industry that builds this stuff. They think most audiophiles are sheep. I left the hi-end audio business for this reason. As a design engineer for a very well known amplifier manufacturer, I got sickened by the "audiophools" comments, and marketing driven design assignments, and the way pricing was being developed. Hearing a discussion about how to increase base margins from 1000% to 2000%, as one example. And this was in the 80's! Now you can buy a $50,000 pair of speaker cable. Ludicrous! Snake oil! There is no manufacturing process, material cost, development cost or anything in engineering that could cause a cable to have to be sold for that price. It is purely profiteering. This is fact.

Now I come to what motivated me to post on AA after all these years. I recently was given a pair of these $50,000 speaker cables by a women who's husband died. A windfall? Ha! Well guess what ... I took a knife to them. They cost me nothing and I wasn't going to pawn them off to some schmuck who worships this stuff. That would be hypocritical of me. But I was curious about what proprietary engineering was justifing these prices, if any. So I cut them open. Removed the beautiful weaving of the outside, pulled back the poly jacket. What I found was shocking. I found a standard Belden branded communications multi-wire underneath. They didn't even get Belden to OEM the cable and not label it. After all, who would cut up a $50,000 cable and find this out? Certainly none of the magazines these days, that's for sure. (I miss Audio Magazine). This Belden wire is a cable that sells for about $2.53 per foot from Mouser. When I priced everything out the cable cost about $270 to make, at retail prices mind you. There was nothing proprietary in this cable and all of the components making it up can be purchased online. They did use an exothermically welded connection on the spades, but other than that nothing out of the ordinary. So how do they justify the price? First by wonderfully talented marketing, maneuvering good mag reviews, techno-babble, and a good dealer network. It is amazing how this alone can change perception while listening.

And BTW, before ripping apart this cable I put a load on it, swept it and measured the frequency and phase response. It was all over the place. The cable certainly would have sounded unique, but it did not pass the signal accurately. In fact, it greatly distorted the signal both in terms of phase and amplitude response and even exhibited IM artifacts as a result, much like vacuum tubes do. It probably sounded very warm as a result. However was it "accurate" or "transparent" or "virtually invisible to the music", as claimed? Not even close. But it probably sounded nice and warm. Did I say that already?

The point being, if you are looking for accurate, most and I mean most Hi-end audio equipment is not actually designed to that end. If you measure things, as I have over the last 30 years, you discover this to be true. But if you don't really care about hearing the music as recorded and want to create an aural aesthetic to your own personal taste, you are in good company. You just need to be willing to pay the price to the snake-oil man just to develop that aesthetic.

In conclusion, if you do the measurements you find two facts.

1. Accuracy is cheaper.
2. Distortion (of facts, physics and sound) is expensive.

So what do you think. Is creating your own aural aesthetic justification enough for the prices you are forced to pay? What's your experiences with measurement? Are you of the belief that human hearing is far better than measurement? Do you believe in angels? Is global warming real? Hehe. You know what I mean. Are the manufacturers engineers or master marketeers or modern day magicians? How much Mrytlewood have you bought?

See Ya!

JRL

Edits: 11/03/12

This post is made possible by the generous support of people like you and our sponsors:

Kimber Kable

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