> Distortion is always there, whether it comes from an imprecise sensor/instrument or from extrapolating sampled data. Specifically regarding the latter part o

> Distortion is always there, whether it comes from an imprecise sensor/instrument or from extrapolating sampled data. Specifically regarding the latter part of "extrapolating sampled data", I would highly recommend watching this video: https://xiph.org/video/vid2.shtml https://xiph.org/video/vid2.shtml. As long as your input signal is low-passed to below 22kHz, the 44.1kHz sampling is perfect. No information is lost, no distortion. I however am not qualified enough to tell you how the naive FFT filter approach changes in distortion as you raise the sampling frequency.