Artificial wow and flutter

Special Interest Groups Audio Processing
1

Good day

I know that there is a software that can remove wow and flutter from samples recorded from a tape or vinyl (for example Capstan). But I wonder whether there is a software that, conversely, can create artificial wow and flutter (I really need that for some sound processing). I don’t think it’s possible with Audacity, but probably you could give me an advise of other ways to do it.

Thanks

2

How about adding a Time Track, and give it a wiggly envelope? (see: http://manual.audacityteam.org/o/man/time_tracks.html)

3

Thanks, that’s a good idea. But the only thing is that if I have even a 5 minute record and the flutter should be about 20 Hz then I have to manually envelope all time track every 0,2 second which is really boring. Is there a way of using preloaded patterns for time tracks?

4

Try pasting this code into the Nyquist Prompt effect and applying it:

;; speed is in rpm
(setf depth 0.004)
(setf speed 45)
(multichan-expand #'snd-tapv *track* 0 (mult depth (sum 1 (hzosc (/ speed 60.0)))) 2)
5

It says “Nyquist returned the value: 45”. Nyquist output is as follows:

error: unbound variable - *
if continued: try evaluating symbol again
1>
6

Sorry, it says “unbound variable - TRACK”, not “*”

7

Assuming that you are using the current Audacity version 2.1.1, ensure that “Use legacy (version 3) syntax” is not selected (see http://manual.audacityteam.org/o/man/nyquist_prompt.html)

(The current version of Audacity is available here: http://web.audacityteam.org/download/)

8

Your “Tremolo/Vibrato” plug-in will do that (on vibrato), but has the added advantage that users can select to have the rate gradually change over time.

9

Unfortunately the “Tremolo/Vibrato” plug-in is not suitable for long sections of audio because cumulative rounding errors (it’s only 32 bit) cause the sound quality to deteriorate when applied to selections much more than a few tens of seconds.

10

And in the following code:

;; speed is in rpm
(setf depth 0.004)
(setf speed 45)
(multichan-expand #'snd-tapv *track* 0 (mult depth (sum 1 (hzosc (/ speed 60.0)))) 2)

by which parameters can I change the frequency and intensity of flutter?

11

(setf depth 0.004)
That’s the "intensity. Larger values for more intensity.

(setf speed 45)
That’s the “frequency”. Larger values for increased frequency.

Note that increasing the frequency will also increase the perceived intensity (because the amount of variation is an absolute amount of time per cycle, so when spread over a longer period it becomes less significant).