It wouldn’t surprise me if under many circumstances a symmetrically designed cable (i.e., a cable having no shield or having a shield that is connected at both ends) were to exhibit directional properties that have nothing to do with the inherent directionality of wire that has been alleged.
A common example of a symmetrically designed cable is a 75 ohm coaxial S/PDIF cable. I would expect such a cable to have small but very possibly measurable differences in VSWR (Voltage Standing Wave Ratio) depending on which way it is connected, due to a combination of soldering differences, mechanical tolerances, small impedance discontinuities in the wire itself, etc. The direction in which it is connected could therefore affect signal reflections and ultimately jitter at the point of D/A conversion.
Similarly, the direction in which a supposedly symmetrically designed analog audio cable is connected could affect energy at RF frequencies that is coupled into or out of the components it is connecting. With the possibility of effects at audible frequencies arising in various ways, such as via intermodulation effects or parasitic diode effects occurring within the components. An extreme example of RF affecting audible frequencies being the many reports that have been seen here and elsewhere over the years of people hearing radio stations when listening to phono sources.
If one has found a symmetrically designed cable to exhibit directional properties, and has verified that the observed directionality is consistent and repeatable across multiple trials, and is not due to extraneous variables such as differences in the warmup state of the equipment, before attributing the difference to inherent directional properties of the wire it seems to me that one must first establish that the cable is in fact symmetrical. And I would feel safe in asserting that no cable is symmetrical to an infinite degree.
So would it be the deviations from perfect symmetry of the cable that are responsible for the perceived difference, or would it be the inherent directional properties of wire that have been alleged by some? As I said here in a recent fuse-related thread:
-- Al
A common example of a symmetrically designed cable is a 75 ohm coaxial S/PDIF cable. I would expect such a cable to have small but very possibly measurable differences in VSWR (Voltage Standing Wave Ratio) depending on which way it is connected, due to a combination of soldering differences, mechanical tolerances, small impedance discontinuities in the wire itself, etc. The direction in which it is connected could therefore affect signal reflections and ultimately jitter at the point of D/A conversion.
Similarly, the direction in which a supposedly symmetrically designed analog audio cable is connected could affect energy at RF frequencies that is coupled into or out of the components it is connecting. With the possibility of effects at audible frequencies arising in various ways, such as via intermodulation effects or parasitic diode effects occurring within the components. An extreme example of RF affecting audible frequencies being the many reports that have been seen here and elsewhere over the years of people hearing radio stations when listening to phono sources.
If one has found a symmetrically designed cable to exhibit directional properties, and has verified that the observed directionality is consistent and repeatable across multiple trials, and is not due to extraneous variables such as differences in the warmup state of the equipment, before attributing the difference to inherent directional properties of the wire it seems to me that one must first establish that the cable is in fact symmetrical. And I would feel safe in asserting that no cable is symmetrical to an infinite degree.
So would it be the deviations from perfect symmetry of the cable that are responsible for the perceived difference, or would it be the inherent directional properties of wire that have been alleged by some? As I said here in a recent fuse-related thread:
... it seems to me that audio is somewhat unique in that there are countless technical variables that can be cited for which it is not readily possible to define a quantitative threshold separating what may potentially be audible in some systems from what is unquestionably insignificant. In the absence of that kind of quantitative perspective there is essentially no limit to what a perceived or claimed sonic effect can be attributed to. Or misattributed to.Regards,
-- Al