Modular Diary – 050

A few weeks ago I tried measuring the pitch deviations of the Analog tuning in the Korg ODYSSEi app using a little patch built in Audulus using the ZeroCross node. It turned out that those measurements were increasingly inaccurate as I progressed up the frequency range, and in the end I turned to another app to map the deviations. Puzzled at the time, I should have taken a closer look at the Audulus docs first, since they provide a thorough explanation of why accuracy decreases as the frequency increases.

The reason for this margin of error has to do with sample rate. At a sample rate of 44.1kHz (the default for Audulus in standalone mode), the ZeroCross node has 44,100 samples per second to evaluate the zero-crossings of a 1Hz wave, whereas it only has 4.41 samples per second to evalute the zero-crossings of a 10,000Hz wave.

Those sample rate considerations also have important implications when creating waveforms digitally. The docs provide, with copious examples, a thorough explanation of what is going on with the Osc and Phasor nodes. A fine, and it seems ever-evolving, resource.

Modular Diary – 050: A few weeks ago I tried measuring the pitch deviations of the Analog tuning in the Korg ODY… rdgr.me/u/wfdb03

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Rudiger Meyer is a composer interested in the play between traditional concert music and new media.


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