If the engineering case against expensive cables is as clear as the evidence suggests, why do so many experienced, intelligent, and technically informed listeners report genuine improvements when upgrading cables? This is a legitimate question, and it deserves a serious answer rather than a dismissal.
The most significant factor is expectation bias — the powerful and well-documented tendency of the human perceptual system to confirm what it anticipates. When a listener installs a cable costing several hundred pounds, they expect to hear an improvement. This expectation is not simply a mental state — it actively shapes perception. The auditory system is not a passive receiver; it is a predictive, context-sensitive interpreter of sensory input. What we expect to hear influences what we perceive we are hearing, particularly for subtle differences that sit at the threshold of detection.
Sighted listening evaluations — the standard format for cable comparisons, where the listener knows which cable is installed — are the conditions most susceptible to expectation bias. When cable comparisons have been conducted blind — where the listener does not know which cable is connected — the consistency and significance of reported differences decreases markedly. This is not an insult to listeners’ perception. It is a finding about human perception under conditions of expectation and uncertainty.
Confirmation bias operates alongside expectation bias. Having paid a significant sum for a cable, and having publicly described an improvement to others, a listener is strongly motivated to continue perceiving that improvement. Reversing the assessment would require acknowledging both a mistaken expenditure and a mistaken perception — a psychologically costly conclusion that most people naturally avoid.
Level matching is another variable that confounds cable comparisons. Even a small difference in signal level between two cables — as little as 0.1 dB, which is not audible as a volume difference but is audible as a quality difference — will cause the louder cable to be perceived as better. Without precise level matching, cable comparisons are evaluating volume differences, not cable character.
None of this means that listeners who report cable differences are being dishonest or unintelligent. It means that auditory perception under uncontrolled conditions is an unreliable guide to physical differences. The experienced listener who takes this seriously will seek controlled conditions before drawing conclusions — and will allocate their budget accordingly.