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Troubles with playing back 96khz sample at 44.1khz

0 votes

I'm working with some recordings in 96khz and 192khz. The recordings has a lot of content over 20khz that sounds nice when pitched down.

I'm running Kyma in 44.1khz and when I play back a sample file (that is in 96khz) the content above ~22khz gets "mirrored" down into the audible range creating artefacts.

If I open the file in the Kyma Wave editor and change the sample rate to 44.1khz (and say yes to interpolation) the problem disappears.

If I run Kyma in 96khz the problem disappears as the ultrasonic content is now played back correctly.

Is there a way to play back a sample file recorded at a higher sample rate without this "mirroring"?

(Maybe I am missing something obvious..?)



asked Jan 9 in Using Kyma by andreas-frostholm (150 points)

1 Answer

+1 vote
Best answer

Frequency content above half the sample rate cannot be represented in a sampled system (so any frequencies above SR/2 appears to be a lower frequency sine wave that goes through those same points; the result sounds like frequencies that are higher than SR/2 "reflect" about SR/2 down to a frequency that can be represented).

If you use the Wave editor to resample the waveform for a lower sample rate, it does perfect interpolation (effectively equivalent to an ideal lowpass filter) to remove any content above half the sample rate.

answered Jan 9 by ssc (Savant) (90,660 points)
selected Jan 10 by andreas-frostholm
Thanks! This was my understanding as well. I like that Kyma is not doing any "behind the scenes" sample rate conversion.