Unshielded twisted-pair wire is probably the best audio signal transfer cable other than fiber optics. Anyone remember Autosound 2000? This was tested years ago by David Navone and Richard Clark.
Shielding acts as an antenna for injecting noise into a signal path. Shielding is only good for high-frequency noise, not the frequencies associated with the dreaded "alternator whine." Car audio companies stress "shielding" because we think a better cable should have it.
A coaxial cable is inherently "noisy" since the two conductors are far apart (center conductor and the outside conductor are separated). Twisted-pair cables place the two conductors as close as possible via the twists.
Most amplifiers use a form of balanced inputs. Any signal (or noise) common to both conductors is removed via difference. Since the two conductors in a coaxial cable (RCA) are far apart, one conductor will always see more "noise" than the other (amplitude difference). The difference in the two conductors can be very subtle (inaudible) or dramatic. A twisted pair cable design helps ensure that the two conductors see the same (or very close to the same) amount of noise (same amplitude). At the input of the amp, the signal common to both conductors is eliminated. If there is an amplitude difference that is dramatic, the signal or noise will pass through. If the amplitude of the signal or noise is the same or very, very close, no signal or an extremely small signal (inaudible) will be amplified.
Scott
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