stranhoROX – Question: Could someone explain to me why there are some recordings with sample rates as high as 192kHz? If most of us hear up to 20kHz, wouldn’t 44.1kHz or even 48kHz be enough? Or is there other practical aspects besides boosting maximum frequency in higher sampling rates I am not aware of?
benski – Answer: There are some advantages to recording, mixing and producing in higher samplerates, similar to using higher bit depths. In particular, non-linear digital audio manipulation will produce overtones according to the order of the equation.
For example, tape saturation distortion has an effect roughly equivalent to output=log(input). If we use the fourth order taylor series expansion of log(x)
We will produce distortion overtones at 4x the frequency of the existing frequencies in the input. Using a higher sample rate can help prevent or reduce aliasing due to this effect. Sure, you can upsample before the effect, and then downsample after, but it might be easier (less CPU) to just have the whole processing chain be 192kHz or 384kHz, and use a lowpass filter before the effect to lop off any input spectra that would lead to aliasing.
Another advantage is that resonant IIR filters (the kind used in synthesizer filters and guitar effects) typically have non-linear responses between theoretical Fc and actual Fc (due to frequency warping and the non-linear effects of resonance, especially if you use a sub-sample delay in the feedback path to compensate for phase differences, see section 5.3 of http://dafx04.na.infn.it/WebProc/Proc/P_061.pdf ). It might be mostly linear, however, to Fs/8, so using a higher sample rate allows the usable audio band to have a linear (and predictable) response to the filter controls.
source: Hydrogen Audio