Background noise suppression glitches as musical material?

General
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I was reading in Mark Fell’s Structure and Synthesis his thoughts on Oval’s Systemisch and Yasunao Tone’s wounded CDs. Later that day, I watched a church service over Zoom and noticed that the background noise suppression did great for people speaking directly into a mic, but really struggled with the choir echoing and resonating in the space, and produced some really unique glitches and feedback.

If Oval and Tone are examples of exploiting the physical medium of CDs for musical material, are there similar works exploiting the idiosyncrasies of digital noise and echo cancellation artifacts?

(More broadly, what works have explored sort of a musique concrete concept moving from analog physical, digital physical, to now streaming? Music exclusively composed from file compression artifacts???)

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Noise reduction plugins typically have a setting where you can hear the noise that’s being reduced on its own, definitely interested in misusing that. Tried the Premiere Pro “remove reverb” thing for a work project and in the course of using it got some incredible weird accidental sounds

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Hi @bw4!j I’m very interested in this topic especially when it borders with information theory, and I’ve dabbled with mp3 compression artefacts in the past. Currently I’m intrigued by Soothe’s resonance suppression and often find myself listening with their delta function (solo the removed sound) on.

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I built a whole track using this technique with Izotope Rx!

I’ve definitely come across some dsp tools that mimic the glitch effect that happens when on a shitty zoom call, or the types of effects you get when you’re on a phone call with someone with bad service. I can’t seem to remember what they were called tho :confused:

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overusing a spectral noise gate based denoiser can add quite interesting artefacts, and it can be worth to subtract the result from the original to only get the artefacts.

but it really depends on the material if you will like it - and it will sound the same everytime you use it.

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I have also been doing this. Really cool! Also Spiff is great for this. Synthesized beats from the delta signal.

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I love these kinds of artefacts ! My personal favorite being the listen on izotope mouth declick, disturbing yet funny.
The bad gate on the choir reminds me of bit reduction on quiet sources, I love the fragilty it can give to the tail of a voice

Do you have any process recommandation ?

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regarding mp3 artifacts, i encountered this article: The Ghost in the MP3 | Semantic Scholar while googling the subject a while ago.

I often use noise removal tools in creative ways, but the resulting sound almost never in isolation. As said above, it is quite a recognizable effect that imho will not stand on its own.
One of the layers at the beginning of this piece of mine is made with Reaper’s reaFIR plugin as a terrible gate (at the very beginning, then resurging around 2m10s).

Maybe this one ?

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From the makers of SketchCassette 2…
Digitalis does this 8 ways from Sunday and it’s only $30.

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i encountered this article: The Ghost in the MP3 | Semantic Scholar while googling the subject a while ago.

Something fascinating about that idea. Has anyone given this a go themselves?

Do you have any process recommandation ?

Over the past day or two I’ve been tinkering with quite a simple python script to carry out the process.

Ryan’s original work is really interesting and well thought out, but I couldn’t find any source code or specific steps for the algorithms he used to perform the subtraction / resynthesize the sound.

A few relevant passages:

From a simple technique such as phase inversion to something as complex as developing a new codec– the inverse mp3,

Two possible ways forward emerge here: we can either
resynthesize the new matrix directly using an inverse
transform or, we can zero the corresponding bins in the
original uncompressed file where the difference is null or
near-null, i.e.- using the MP3 as a mask on the original
file

(the “new matrix” he is referring to corresponds to taking the difference bin by bin between the original / compressed spectra)

I’ve got a few different approaches in the script, just for experimentation and seeing what works out best.

  1. Just performing a regular complex subtraction of the polynomial complex no. representation of the data. This means that the magnitudes / phase are not handled separately
  2. Converting to polar representation and subtracting the magnitude and phase separately before converting back into polynomial representation and doing an inverse short time fourier transform
  3. Zeroing the bins in the original spectra where the difference in the magnitudes (mag_orig - mag_compressed) is < some threshold

Each lead to slightly different and yet somehow unsatisfying results. I mostly just get out either a noisier or quieter version of what I put in. But I’ll keep on experimenting, there are a few other points Ryan mentions which I haven’t done: dropping phase entirely, performing a constant-q transform after the STFT etc
I’d also like to get the set of files he was using in his original analysis for comparison, but they’re not downloadable from his SC :cry:

Anyway, for anyone who would like to use the script the dependencies (for python3) are: pydub (for mp3 conversion), matplotlib, scipy & numpy. I think the only change necessary to get it to run is to change the path to the audio input file towards the bottom

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I have one - sort of - where I used noise reduction at it’s most extreme setting to isolate the tones created by the wind blowing through construction scaffolding (which created an aeolian harp).

I released both the processed recording and the field recording on two different labels and then rereleased the lot on my own label years later.

Here they are - the 1st and 3rd tracks are two versions of the treated field recording (again - just extreme noise reduction, nothing else) and the middle track is the original field recording.

There’s also this brilliant one by ayrtbh - more on topic than mine tbh:

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I played with this a bit, really cool idea to automate it. I’ve found softer breathier stuff can produce some really cool resonances