CardinalFang;156895 Wrote: > I don't think we're talking about cables wearing out as such, but there > is degradation due to corrosion and UV light on insulators for example. > The question is, is this a positive or negative effect? If you are > carrying AC power to a motor, it really doesn't matter if there's a > tiny bit more resistance, but since AC at higher frequencies travels on > the surface of cables, a corroding surface may well make things worse > for audio - or just different.
Surface corrosion of copper cables would effectively make the cable slightly thinner...with the current now flowing in this thinner cable. This would make little difference until the cable got exceedingly thin. Agreed there is a slight skin effect at higher frequencies. Whether this is a phenomenon that actually has an audible impact will I believe remain an audiophile discussion topic 'till the ends of time. This is indeed fortunate, for if there were nothing to argue about, life would be that much duller. I am of the what I would categorise as the 'practical engineering' school of thought, or listening and would submit that skin effect does have an impact, but not an audible one that I need to worry about. Elsewhere I believe I have admitted to being totally deaf, so I am discounted as a real audiophile (even although I am very handsome), but I remain fascinated by arguments involving physical phemonena. I refer you to http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/audio/Analog.html for an excellent discussion on skin effect and other audio stuff. (the fact that I'm Scottish myself has of course biased my thinking here) One quote from this paper in relation to skin effect is as below: "Despite the above, to an acoustic engineer the delays seem very small. Since sound propagates at a velocity of around 330 m/sec it will only travel around 16 microns in 50 nanoseconds. In effect, therefore, the above differential group delay is equivalent to a sound source that seems 16 microns nearer at high audible frequencies than at low audible frequencies. Again it is not clear that this would be noticeable in a practical situation." 16 microns is pretty small. Not zero, but small. Thinner than the wax in my ear that's for sure. I have to also consider this 16 microns distance due to electronic skin effect to the equivalent situation when one is in an audience listening to perhaps the original music itself, lets say 20m from the stage. Since high frequency sound is attenuated in air much more than low frequency, (thunder cracks at low distance, rumbles at far distance), would the listener in the audience be more affected by differential attenuation of sound spectra in air than would be the same individual listening to the same signal from a hi-fi system in his home, sitting perhaps 3m from the speakers? So if you are still worried about skin effect in cables, maybe you should also sit closer to your speakers to reduce the attenuation effect of high frequency sound in air. dan -- chinablues ------------------------------------------------------------------------ chinablues's Profile: http://forums.slimdevices.com/member.php?userid=7955 View this thread: http://forums.slimdevices.com/showthread.php?t=29025 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
