Even with poor-quality wire, an audible degradation of sound may not exist. Many supposedly audible differences in speaker wire can be attributed to listener bias or the placebo effect. Listener bias is enhanced in no small part by the popular manufacturers' practice of making claims about their products either with no valid engineering or scientific basis, or of no real-world significance. Many manufacturers catering to audiophiles (as well as those supplying less expensive retail markets) also make unmeasurable, if poetic, claims about their wire sounding open, dynamic, or smooth. To justify these claims, many cite electrical properties such as skin effect, characteristic impedance of the cable, or resonance, which are generally little understood by consumers. None of these has any measurable effect at audio frequencies, though each matters at radio frequencies.
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