Sampling rate divisible by each frequency creates ugly sub-signals with uneven peaks

vincentlou-git / aumix

Audio Unmixing and Music Score Transcription. Developed as my undergraduate final year project.

https://doramemo-x.github.io/aumix

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Sampling rate divisible by each frequency creates ugly sub-signals with uneven peaks #28

Open vincentlou-git opened 3 years ago

vincentlou-git commented 3 years ago

Is the audio fine? If so then it's probably ok....?

vincentlou-git commented 3 years ago

This likely isn't a bug, but an artefact of a finite sampling rate

vincentlou-git commented 3 years ago

This seems to cause "shaky" audio - the amplitude is oscillating up and down noticeably.

vincentlou-git commented 3 years ago

Pure tone chords can induce constructive / destructive interference, causing the "owowowowowowowo" shaky sound. Upon further investigation in MuseScore, MIDI violin (strings) chords has an even more profound effect, while that of a clarinet (woodwind) is less noticeable but is still slightly there. Trumpets (brass), voice (vocal), and piano (keyboard) don't produce this "vibrato" effect.

vincentlou-git commented 3 years ago

Potentially useful to describe the natural vibrato: https://online.ucpress.edu/mp/article/38/3/282/116128/Timbre-Vibrato-Perception-and-Description

vincentlou-git commented 3 years ago

~~Potentially useful: Producing undistorted acoustic sine waves https://newt.phys.unsw.edu.au/jw/reprints/Predistortion.pdf~~