hobbyist wrote: CS70 wrote:
hobbyist wrote:Theory says that the higher rates are better.
No, the theory doesn't. :-)
Okay -- Theory , with a perfect recovery is perfect.
But there are always errors in real life ; and in real life higher sampling rates could benefit the accuracy of the result IF the A/D errors and clock jitter are small enough.
Yes, the math is clear: sampling at double the Nyquist rate maintains all the information in the sampled signal, so the theoretical reconstruction is perfect. There is no
information loss. So you don't need anything more.
As of these bothersome engineers, yeah the poor fellows don't seem to be able to mach the beauty and perfection of the math. :D How annoying. But you gotta understand why and what!
For example, increased sample rate require a faster
clock! And the faster the clock, the more small inaccuracies in timing become significant. So the higher the sample rate, the more accurate the clocking must be, which as the Romans found out, is quite a lot harder than making a less accurate one. So jitter is a bigger
problem at higher sample rates: with the same components and tolerances, you're likely to have a more error in the reconstructed signal, not less - read: worse sound.
As Hugh can explain much better than I, the main issue is that real world lo-pass filtering (which is required to limit the signal to the 20-20K band) is not as perfect as it should be. This in turn may allow some ultrasonic content to alias back in the hearing band. Most mics roll off anyway pretty sharply after 20K, but of course there's some recorded signal that may have content there. 96KHz may help there. Lots of plugins do oversampling for that reason. Tough it helps only if you have ultrasonic content in the first place. I remember he mentioning drum cymbals as a typical source which can benefit (as it's more likely to produce significant ultrasonic energy, which survives the mic roll off attenuation, and may thus get aliased back in the hearing band).
On a practical view tough, I never heard anybody say "hey these cymbals sound odd, probably they've been recorded at 44.1Khz" :-D
Also, keep in mind that 96KHz may put the analogue part of your chain under more strain - and especially with lower end kit, most of the testing has probably been done at the "regular" sample rates. To go over 96Khz for normal musical applications is ... not well thought thru ;-)
Unless it's marketing of course - preying on the honest desire for quality of customers to sell them stuff and even worse, convincing them that the bs is real..