The root of the problem is that there is no easy way to assess absolute sound quality, it’s very subjective. This Audiophile nonsense is very much like the Emperor’s Clothes, e.g.
Timing and coherence are the two really easy differences to hear, but like other interconnects it’s simple to spot the differences in levels of detail, tonal quality and dynamic performance.
i.e. If you can’t hear the difference you’re a moron.[/quote]
That’s not strictly true – all of those things can be measured fairly accurately, using, in some cases, a number of scales. That said – it’s a real faff to measure them, and the differences between the measurements are difficult to actually assess unless you have some kind of reference – as with many audio things, they mean little to nothing in a vacuum.
<geek>
Timing – at this level, you’d be measuring this on the basis of system/interconnect jitter, which is related to the quality of the clocking of the system. This *can* have an impact on the consistency of playing back the samples – these should be precisely every whatever milliseconds depending on sample rate – if this drifts, due to poor clocking, then it can impact on phase alignment, but only really when you have more than one cable or system transmitting audio – i.e. it’s of little to no consequence here, because we’re only dealing with a single stereo/greater than stereo signal, not multiple signals from multiple sources being brought together – like in a mixer. You can measure jitter pretty easily by checking the consistency of the sample data in the cable – this is something you can do straight out of the cable itself.
Coherence – I’m assuming this means phase coherence, rather than anything else, and this again, can be an issue, if the left channel arrives at a different time from the right channel then you end up with a skewed stereo image, and potentially comb filtering impacting on the overall tone. However, a cable wouldn’t improve or deteriorate this – even in a system (like optical cables) where the stereo data is sent serially – i.e. left content followed by right content – then the problems could only occur in the reconstruction of it, not the interconnects. You can measure this by comparing the input signal and the output signal – although isolating the cable would be basically impossible – it needs convertors etc. to be able to do the calculations, and then if you changed the cable you’d need to take into account the changes in the rest of the circuit because of the changed cable – but you could come out with something – it’s unlikely to change, but you’d have a difference.
Detail – this is probably the most bollocks on there, the only thing I can think of is total harmonic distortion (THD) to measure this…but a digital cable would need to be seriously crap to have an impact on it, in fact, the point at which a digital cable is impacting on this, you’d end up with no signal.
Tonal Quality This is easily measured by comparing signal in to signal out and identifying areas of difference. This doesn’t mean that change = bad, because I know a heap of people who choose stuff (mixers, EQ, compressors, speakers) because they do change the sound for the better.
Dynamic performance This is crudely measured as an RMS average over time, or more usefully using Bob Katz K system, it has a specific calibration process and meter ballistics to follow, meaning you can compare apples with apples through the system and give you a good idea about relative dynamic performance.
Posted 10 years ago