Cable Sounds and

Arguments about the ‘sound’ of audio cables crop up with monotonous regularity on the newsgroup (and elsewhere!). Usually, this arises when someone posts a message claiming that they can hear “obvious differences” between one cable and another. This then prompts responses which challenge/doubt/attack/dismiss the claims. The resulting posts then usually go over much the same ground as on many previous occasions. Sometimes venomous arguments develop which do not really help to clarify the matter.

The purpose of this webpage is to summarise some of the basic, recurring, points that I would personally tend to make in such discussions, so as to avoid having to re-write them on each occasion. I hope that what follows will be useful as a summary/reference for those involved on and elsewhere. It should serve as a start-point and avoid the need to make the same points repeatedly on the newsgroup.

Set of basic comments
With the exception of a few specific situations (detailed later) the following comments can be made with regard to the argument about ‘cable sound’ in audio:

Exceptional cases
There are some specific situations where swapping one cable for another may well cause an audible change to the sounds produced by an audio system. These may be summarised as below, and can be regarded as exceptions to the above. In these exceptional cases there are well-known reasons in terms of the relevant physics, etc, to expect and audible effect when one cable is replaced by another.

Each of the above represents in engineering terms a well-known effect that can be measured and avoided. Hence they are not regarded as contentious. In general, the above situations would tend to be regarded by engineers as a fault or imperfection in the system/cable that should be dealt with and removed. For these reasons if someone on says that they doubt that a change of cable will physically alter the resulting sounds, then the above cases may regarded as being exceptions to that statement.

As a result, arguments about ‘cable sounds’ should be limited to situations where it is established or agreed that the situation is such that none of the above are likely to be the cause of a claimed alteration in the sound when one cable is replaced by another.

Assessing claims
Given the above, I, and various others on, rather doubt (excluding cases covered by the exceptions described below) that the claims made are reliable. Speaking personally, I regard it as a pity that people make the claim, and then refuse to put it to a suitable test. As a physicist/engineer I’d love to discover that audible ‘cable sounds’ arise which were not due to one of the above exceptions. This would imply there was some ‘new’ physics to be discovered, and I would find this both interesting and exciting. I would also welcome finding that – despite my experiences to the contrary so far – that I could get an improved result by such means since I do enjoy listening to music via the audio systems I use.

I am therefore disappointed that people keep making claims, and then refuse to even try to show they can actually hear what they claim.

This refusal to engage in such a test keeps the claims to having the status of being a ‘belief’ which they hold, and expect others to accept on as a matter of ‘faith’. Hence we are unable to resolve the matter since those making the claims decline to make this possible. Yet many of us do not hear what is claimed, and when people have tried in tests, the results do not support this belief. Hence my doubts, and those of others. Again, speaking personally, I am not attracted to the idea of applying a ‘faith based’ approach to such a topic. It seems to me that the scientific method is more likely to prove useful. But can only be the case if at least some of those who make the claims are prepared to engage in suitable tests which could then provide relevant evidence, as distinct from personal opinions/beliefs.

The above does not mean I regard those making the claims as being liars or fools. Nor do I necessarily think that no audible differences can ever have occurred in at least some of the reports. If we ignore the possibility of one of the above exceptions having occurred without the claimant being aware of it, there are still many reasons why someone might come to believe that a change of cable altered the sounds, when this was not actually so. Here I can give some examples.

Physiological Effects. If we examine the research literature on the physiology of human hearing we can find measurements and other tests which show that the biomechanics of hearing are altered by various factors. One of the most well-known of these being that the sensitivity of hearing physically alters as a result of listening to loud sounds. This can change the response of the hair cells in the ears, and the output patterns sent to the brain. Some of these changes are temporary and the ears ‘recover’ after a period of minutes or hours. This means that if we listen to the same recording twice in succession, our ears may simply respond differently the second time around.

In addition to the above, becoming tired, or alert, or the diurnal cycle can alter the biomechanics of human hearing. As can illness, etc.

Psychological Effects. The most commonly mentioned effect in this class is what people call “expectation” when referring to a pre-conception that a given cable has a given effect upon the resulting sound. Put most bluntly this tends to be phrased along the lines of, “If you spend a fortune on a cable you will wish to hear an effect that makes the results sound better!”

However even if we discount the above, there is a more subtle problem. This is due to the way the music/speech used for any comparison has been chosen and used. If we use a different recording each time we changed cables, then it would become almost impossible to tell if any changes were due to the change in the recordings. Hence the tendency is to use the same set of recordings and play them via each choice of cable in turn. This nominally ensures we are comparing ‘like with like’ so far as the source material is concerned.

The difficulty with this approach is that the listener, when listening, will tend to notice particular features or details of the sound on one ‘play’, and then may find they are listening for them again the next time the same recording is played. This means they may tend to ‘focus’ on some detail and hence are listening in a different manner to the previous occasion. This tendency should be a familiar one to many people who enjoy listening to music. When we listen to music repeatedly we tend to both look for some anticipated details, and hope to discover new ones each time we listen. If the sounds are reasonably complex this means that we may mentally ‘pilot our attention’ through the music in a different manner from one occasion to another. Indeed, we may either find more to enjoy, or become bored. This implies that we are not actually listening in the same way every time, and our ability to judge what we hear is being altered by the act of having previously heard the recording.

Acoustic Effects. Slight movements of the head/ears whilst listening can also change the sound patterns reaching the ears to a significant degree. As can any movements of the speaker positions, or the opening or closing of the doors of the listening room, or movements of the furniture. Such changes are also easily demonstrated by making acoustic measurements. Even the attenuation properties of the air will vary with humidity and temperature.

Equipment Variations. It may be the case that the signal level was not kept the same during each period when cables were compared. Or, for example, that the speakers in use changed their properties as a result of being used for some time.

The above set of examples is not meant to be exhaustive or to be the ‘reason’ for all cases where people make claims. However it serves to indicate that unless great care has been taken to deal with issues like the above, that there may be good reasons to suspect that a claim that a change of cable alters the sound might actually be due to some other cause that has nothing to do with the cable as such.

I do not doubt that the arguments over ‘cable sound’ will continue, and people will continue to make and sell expensive cables. Some people will buy these and pronounce that they very pleased with them. Others will insist this is all utter nonsense, and that people are being deluded. I suspect this will continue until some of those making the claims actually come forwards and start participating in tests designed to resolve the issue. Until then, my personal position is to be sceptical for the reasons outlined above.

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