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I want to get some sort of garbling effect over voice audio files. sox has many effects available, but I don't know how to get the desired result.

sox man page, listing available effects.

This is an example of the original voices, and this an example of the resulting audio. I would like to get as close as possible to the second example, although a similar distorsion would be acceptable as well if it sounds fine.

If it's not possible with sox, but you know how it might be achieved, please, let me know.

Just for clarification, sox is a command line program for audio manipulation.


Ring modulator distorsion with SOX

Thanks to the answer I've been able to achieve the effect using solely sox. Here's an example.

Create sinus wave (40 seconds long).

sox -n -r 22050 sine-500.wav synth 40.00 sine 500

Multiply it by the input we want to distort (should have the same duration and sample rate).

sox -T voice-input.wav sine-500.wav distorted-voice-output.wav

The sinus wave can still be heard in the back. You can filter it like this. (The sine wave had a frequency of 500 Hz).

sox output.wav output-filtered.wav sinc 750-250
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I may be wrong but this sounds to me like a simple ring modulator.

  • Thanks a lot! I can't verify it myself, but I asked more people and their answers are consistent with yours. – Calculus Knight Aug 13 '17 at 14:50
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    You're welcome. I didn't look much into sox but I think you can get a ring modulation effect if you multiply the amplitude (level) of your signal with a fixed frequency. I'd start somewhere around 100Hz. So every sample value gets multiplied by the corresponding momentary value of a sine wave at that time. – Schizomorph Aug 13 '17 at 15:45
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    I just wanted to say thank you again and point out that I've completed the answer by adding instructions on how to achieve the Ring Modulator distortion effect using sox alone. Thanks! – Calculus Knight Sep 23 '17 at 20:56
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    Nice. I don't even know what sox is but you got me curious now and I'm going to look it up. – Schizomorph Sep 23 '17 at 21:06
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    I might have to revive my linux boot to try it out. Interestingly, I just started playing with audio with python and pyaudio. Well, all I have so far is a program that tells you what audio devices are in the system but it's been less than a week since I started. – Schizomorph Sep 23 '17 at 23:28

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