Does copper cable produce better sound? Unexpected test result

The moderator of the diyAudio forum, signed as Pano, prepared a blind testin which four 30-second versions of the same fragment are available for listening: the original file, the recording passed through 180 cm of professional copper cable, through 20 cm of wet mud (in combination with 120 cm of copper) and through 13 cm of banana (also with 120 cm of copper). Respondents were asked to determine how the sound signal was conducted in a given recording.

The answers were very off the mark — out of 43 entries, only 6 types were correct, which gives about 14% hits. Statistical analysis showed that such an outcome could happen by chance with a probability of several percent. In other words – bananas and mud sounded almost the same as copper cable, at least for the participants in this test.

What sounds like a joke, however, is quite simple physical explanation. Introducing a banana or mud into the signal chain is effectively like adding a resistor in series – it lowers the signal level, but does not necessarily introduce audible distortion at line level. Our listening systems and brains can compensate for such volume differences, and with short passages and typical consumer equipment, subtle changes are lost in the noise of perception.

This is not proof that cables don’t matterbut a strong reminder that confidence in subjective assessments often outweighs actual differences. There is a powerful mix of physics and psychology at work in the audio world: expectations, suggestion and context can do more than a few centimeters of wire. Blind tests are the only honest way to separate the real effect from the placebo.

Who is this good news for? For sensible buyers: if your systems are properly tuned and the cables are not physically damaged, investing in marketing promises of a “magic” cable may give more mental satisfaction than real improvement in sound. For producers and sellers, it is a reminder that storytelling sells, and science sometimes spoils the fun. For passionate audiophiles — nothing stops you from enjoying your cable collection; but it is worth remembering that subjective certainty does not replace a controlled test.

The Pano experiment also has educational value. This is a perfect example of how easy it is the mind adjusts its feelings to expectations. When we know that we are listening to a “special” cable, we are more likely to notice the differences.