Audio - Snapping at Zero Crossing: Timing Errors

Here I'm going to post a few tips for some snapping features that can offset an audio clip when cutting/copy/pasting and such (this applies to Sonar 7 in particular):

Audio zero cross - it's an option - disable it for Cut/Copy/Paste on audio clips to eliminate timing errors. I realized this when I cut and copied a few clips and realized two adjacent tracks were 'chorused' due to a very slight delay. Sure enough, zoomed out in normal viewing the clips looked perfectly aligned to the measure. Zoom in, whammo, you've got yourself a few millisecond delay. This will happen when the snapper tries to hunt for a zero cross on the audio waveform... the intent is to eliminate any sharp/loud clicks/pops due to high volume levels on the transition of a repeating audio clip. Unfortunately, this can and probably will cause timing issues!

The timing error will likely be small... think about it... even a perfect single note on guitar (well, it'll never be a 'perfect' sinusoid), let's say it's the low-E at ~80Hz... the time from zero to zero cross is T/2 or 0.0125/2s or 6.25ms! The low E on a bass guitar will be roughly double or 12.5ms. Thankfully though, many sounds are not pure clean single tones (esp. heavily distorted notes or chords, etc...) and the zero-crosses will occur more often, decreasing this time. Just be aware if you do use this operation that there will be an error added! If you were to paste several of the same audio clip serially, the timing error will sum.

If you do get a loud bleep at the transition of an audio clip, you can try using crossfades or a quick single fade.

- Phil