|Originally posted by Joe Bloggs
Dammit, Ricky, what is your definition of a significant change in sonic character caused by different electrical measurements?
The term would be "electrical parameters". Electrical parameters can be measured, and are independent from the type of signal you are passing through them. Electrical parameters are harder to measure than just the effect of the cable over an audio signal. So when I say that I can't measure differences between cables for audio signals, I'm not talking about electrical parameters, but about the measurable effects of the cable over the audio signal.
FR--0.01dB down at 20kHz? 0.05dB? 0.1dB? 1dB???
Phase shift--0.05 degree, 0.1 degree, 0.5 degree, 1 degree, 10 degrees???
About effects of equipment or any other kind of device over audio signal, and according to Arny Krueger, a quite knowledgeable person on audio subjects:
"If all forms of nonlinear distortion and noise are > 100 dB down,
frequency response is within < +/- 0.1 dB, there is less than 5
degrees of differential phase shift between the channels, and less
than 45 degrees of total phase shift 20-20 KHz with a phase slope of no more than 22 degrees per octave, then it is quite assured that the equipment has no *sound* at all."
For high frequencies, it is quite difficult for many people to distinguish a lowpassed 16 KHz musical clip from a non-lowpassed one. I'd dare to say that a lowpassed 18 KHz musical clip would be inaudible for nearly everyone. Examples of this at http://www.pcabx.com/technical/low_pass/index.htm
At frecuencies very sensitive for human ear, being 4 KHz the most sensitive one, I think it's agreed that differences over 0.3 dB are not so difficultly perceivable.
|Or is the standard being 'my crappy radioshack multimeter can't measure any difference between the two cables when connected to my crappy computer so they must be the same down to the 10th significant figure'???
Of course not. To do some significant measurements on audio signals and alterations, it is necessary to use a fairly reasonable quality soundcard, being advisable a 24/96 type, and adequate software. The better the card, the more resolution of measurements. Lots of measurements of audio equpment, including audio hardware used to do the measurements, at www.pcavtech.com.
I know it seems I'm making free propaganda of Arny Krueger's sites, but this guy has lots of useful info at his pages.