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Technical and scientific discussion of amps, cables and other topics.

RE: This are honest questions...............

I'm glad you ask.

I can measure changes in amplitude response down to less than .005dB for signals. For SPL I can measure at a resolution of less than a 10th of a dB SPL. Time can be measured in nanoseconds. Phase within a fews seconds of degrees.

Human hearing, at best can discern SPL changes at an absolute limit of about 1.5dB SPL. Time differences can be heard to just above 10 microseconds. Phase down to about 1 degree. This has been tested extensively and retested and refined dating back to the beginning of the 20th century by people like Munson, Heinrich Wilhelm Dove, Helmut Haas and others. Today in Audiology these limits are well understood, although not in the common knowledge.

Yes, training can aid in increased ability to differentiate sounds and levels. Professional recording engineers have this refined skill. So do some musicians.

I made blanket statement since most of this information is already widely published and accepted in academia. It is however not always in the common knowledge and that fact is what the audio companies prey upon.

Perception of audio can be influenced by words, emotions, diet, drugs, time length and volume of listening sessions, suggestion, etc. It varies by ethnicity, environment, age, & health.

I read here about people burning-in cables, listening for hours and then claim to hear a warming of the sound over time. Most likely it's simple ear fatigue. Using a cable does not change its molecular structure, align molecules, or change in any physical way the wire or insulation. People have been trained to believe this. I can tell you with all certainty this is a false assumption and myth. What people are hearing is change in perception, not the cable. It is much more easy for perception to be changed than the molecules of copper to be transformed by use. The physics do not support it, the measurements and testing dispute it. However, change in aural perception can change to a great degree and in a short time by simply eating garlic, smoking a cigarette, having a slight change in humidity or pressure.

Which do you think is more likely? Something happening that defies physics, or assumptions made because of something as transient as perception? I know it's the latter, in this case. I've done the science.

Burning-in electronics is something different and there are changes that are real in that case.

However, do not misunderstand me. I am not saying that there are no differences between these varied products. Indeed there is. My point is most are intentionally designed deviations away from accuracy, for the sole purpose of being different. In know this from being a designer/engineer for these companies. These goals are laid out as criteria goals for the design teams, in many cases. "Make it warmer" or "make it brighter". Rarely is it make it accurate.

One example is the best clocks available for audiophile DAC use are in the 10ppm accuracy range. And these sell for tens of thousands of dollars. Where professional clocks are more accurate by a factor of 100, and in some cases are more accurate than the NIST calibrated time measurement devices used to test such specifications. And they cost less than $2000.

Now if you like I can tell you about the acoustic properties of Myrtle wood. :-)

JRL




Edits: 11/03/12 11/03/12 11/03/12

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