Professor Milind N. Kunchur has this line of thoughts:
"The influence of interconnecting cables on an audio system’s performance is a controversial issue. This is partly because commonly measured parameters such as resistance, reactance, frequency response, and common distortions do not show meaningful differences. The present electrical study of line-level single-ended (unbalanced) analog interconnects, provides a more comprehensive picture surpassing the common specifications. It was found that uncommon time-domain effects such as reflection sequences and non-ideal capacitive behavior, along with noise, can better distinguish the electrical performance of interconnects of different grades."
See his study papers:
An electrical study of single-ended analog interconnect cables
It is not an easy read, but it seems the key to unravelling all these twisted knots in cable audibility lies in analysing even more precision measurement parameters beyond frequency response, resistance, and nominal reactance.
Summary and Conclusions
The effect of cables on the sonic performance of an audio system has been a contentious subject for a few decades [31]. The controversy is fueled in part by the paucity of journal-published blind listening tests that prove there is at all an audible difference. Listening tests are tricky and can easily produce both false negative and false positive results; the relevant psychology and neurology is reviewed in [1, 32–36]. Another reason for disbelief in interconnect audibility may be due to a misguided focus on irrelevant measurements such as frequency response, resistance, and nominal reactance, whose resulting signal errors are indeed far below the presumed audibility thresholds.
The present work investigated other kinds of signal alterations during transmission through a cable, besides the above parameters. It was found that noise in some cables exists at audible levels. While the nominal reactive time constants may possibly be too short (<100 ns) for discernibility, the decay times arising from non- ideal effects are not obviously negligible (~1 ?s), especially when multiple occurrences combine along the audio chain. Within the audio community at large, there tends to be a misunderstanding and underestimation of the spectacular capabilities and extraordinary sensitivity of human hearing: For example, the ear can detect a cochlear basilar-membrane amplitude of ?1 pm [37–39] and has a temporal resolution in the microseconds that has no direct connection with the maximum audible frequencyk.
The present work found clear systematic differences in the electrical performance of interconnect cables of different grades. Besides the electrical signal alterations studied here, vibrational effects (“microphonics”) may also potentially affect cable performance [17]. However unlike loudspeaker cables, interconnects lie in high impedance circuits and carry low currents. Thus they have smaller magnetic forces and induced voltages from mechanical motion. Another potential source of signal degradation in cables is triboelectric noise from internal motion; but it is estimated to be 180 dB below typical signal levels [45].
Previous work [1] demonstrated the audibility of cable pathways, pointing to differences in RF noise pickup as the likely cause. But it left open the question of whether the noise differences were due to shielding or balanced versus unbalanced topologies. The present work sheds light on that question by showing that its unbalanced cable S (of the same brand as cable A in [1]) is almost equally quiet. Furthermore, there are clear time-domain performance differences between the various interconnects tested. While cable manufacturers undoubtedly make a variety of measurements on their own products during the course of their development, the present results are of value to the consumer because they provide measurements across different brands made by a non-commercial entity.
"The influence of interconnecting cables on an audio system’s performance is a controversial issue. This is partly because commonly measured parameters such as resistance, reactance, frequency response, and common distortions do not show meaningful differences. The present electrical study of line-level single-ended (unbalanced) analog interconnects, provides a more comprehensive picture surpassing the common specifications. It was found that uncommon time-domain effects such as reflection sequences and non-ideal capacitive behavior, along with noise, can better distinguish the electrical performance of interconnects of different grades."
See his study papers:
An electrical study of single-ended analog interconnect cables
It is not an easy read, but it seems the key to unravelling all these twisted knots in cable audibility lies in analysing even more precision measurement parameters beyond frequency response, resistance, and nominal reactance.
Summary and Conclusions
The effect of cables on the sonic performance of an audio system has been a contentious subject for a few decades [31]. The controversy is fueled in part by the paucity of journal-published blind listening tests that prove there is at all an audible difference. Listening tests are tricky and can easily produce both false negative and false positive results; the relevant psychology and neurology is reviewed in [1, 32–36]. Another reason for disbelief in interconnect audibility may be due to a misguided focus on irrelevant measurements such as frequency response, resistance, and nominal reactance, whose resulting signal errors are indeed far below the presumed audibility thresholds.
The present work investigated other kinds of signal alterations during transmission through a cable, besides the above parameters. It was found that noise in some cables exists at audible levels. While the nominal reactive time constants may possibly be too short (<100 ns) for discernibility, the decay times arising from non- ideal effects are not obviously negligible (~1 ?s), especially when multiple occurrences combine along the audio chain. Within the audio community at large, there tends to be a misunderstanding and underestimation of the spectacular capabilities and extraordinary sensitivity of human hearing: For example, the ear can detect a cochlear basilar-membrane amplitude of ?1 pm [37–39] and has a temporal resolution in the microseconds that has no direct connection with the maximum audible frequencyk.
The present work found clear systematic differences in the electrical performance of interconnect cables of different grades. Besides the electrical signal alterations studied here, vibrational effects (“microphonics”) may also potentially affect cable performance [17]. However unlike loudspeaker cables, interconnects lie in high impedance circuits and carry low currents. Thus they have smaller magnetic forces and induced voltages from mechanical motion. Another potential source of signal degradation in cables is triboelectric noise from internal motion; but it is estimated to be 180 dB below typical signal levels [45].
Previous work [1] demonstrated the audibility of cable pathways, pointing to differences in RF noise pickup as the likely cause. But it left open the question of whether the noise differences were due to shielding or balanced versus unbalanced topologies. The present work sheds light on that question by showing that its unbalanced cable S (of the same brand as cable A in [1]) is almost equally quiet. Furthermore, there are clear time-domain performance differences between the various interconnects tested. While cable manufacturers undoubtedly make a variety of measurements on their own products during the course of their development, the present results are of value to the consumer because they provide measurements across different brands made by a non-commercial entity.
