I have a low quality
24 kHz mp3 voice and I'd like to upsample it to
48 kHz for farther mixing with another
48 kHz track.
What is the right steepness curve in this case? I'm going to use an ideal low-pass filter with:
Filter steepness=2000 Cutoff shift=1 Pre-ringing=1
but I'm not sure if that would create noise/artifacts or degrade the signal?
Low steepness creates artefacts.