Batch denoising of an Ardour session

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unfa
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Batch denoising of an Ardour session

Post by unfa »

Hi everyone! :)

I have recorded a song with my band in a multitrack Ardour sesion, but after the recording was done, I've noticed that every recored region has a static tone present spread all over the frequency spectrum.

It was caused by an old amplifier we used to deliver headphone signal to the musicians (ironically we could easy do without it and the problem would not exist...)

Here is a sample from the recorded bass track: http://unfamusic.com/5h1+/noise-sample.ogg

I have about 166 wave files (total size of about 1.4 GB) to denoise, so doing it manually in Audacity one-by one doesn't seem like a solution to me. It's batch processing always have given me problems with file names (adding a 1 to every exported file) so I don't know if I can use this either.

I have also recorded several minutes of the noise alone for further use in de-noising, but I can't find any program that could do it.

I'd be really grateful if you guys could help me :)

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Capoeira
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Re: Batch denoising of an Ardour session

Post by Capoeira »

I have no idea if this works or is any practicly, but perhaps you could add a track with the noise to every track in Ardour and than invert it to cancel it out

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unfa
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Re: Batch denoising of an Ardour session

Post by unfa »

Capoeira, I think that could be a an option for a single track. I'd need to get a sample-exact phase-matching for two several-minutes-long tracks. But still that would multiply white noise amount by 2, as even if the static tone would cancel itself, the white noise component will surely not (as it is non-repetive). For a multitrack session this seems too much work.

I'm looking for some CLI (command-line interface) program that I could write a bash script to use it for batch processing of all 166 files.

I wonder if I could be capable of writing such an app if nothing shows up...

Still searching.

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Capoeira
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Re: Batch denoising of an Ardour session

Post by Capoeira »

a quick search in my package-manager gave me this, perhaps it can help: http://eca.cx/ecasound/

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raboof
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Re: Batch denoising of an Ardour session

Post by raboof »

unfa wrote:I have about 166 wave files (total size of about 1.4 GB) to denoise[, so doing it manually in Audacity one-by one doesn't seem like a solution to me. It's batch processing always have given me problems with file names (adding a 1 to every exported file) so I don't know if I can use this either.
(..)
I'm looking for some CLI (command-line interface) program that I could write a bash script to use it for batch processing of all 166 files.
I'm not familiar with audacity's batch mode, but if it works, you could of course write a bash script to drop the '1' audacity added to all exported files :). Something like:

Code: Select all

$ mkdir exported
$ mv *.1 exported
$ cd exported
$ for i in *.1 ; do mv $i `basename $i .1` ; done

joaquinotero
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Re: Batch denoising of an Ardour session

Post by joaquinotero »

Hi, could you tell me please where I can find the plugin for denoising?

Ive been searching in the hundreds of plugins in Audacity and I cant find it.

Thanks a lot for your help.

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autostatic
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Re: Batch denoising of an Ardour session

Post by autostatic »

Effect - Noise Removal

Frank Carvalho
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Re: Batch denoising of an Ardour session

Post by Frank Carvalho »

unfa wrote:Capoeira, I think that could be a an option for a single track. I'd need to get a sample-exact phase-matching for two several-minutes-long tracks. But still that would multiply white noise amount by 2, as even if the static tone would cancel itself, the white noise component will surely not (as it is non-repetive). For a multitrack session this seems too much work.

I'm looking for some CLI (command-line interface) program that I could write a bash script to use it for batch processing of all 166 files.

I wonder if I could be capable of writing such an app if nothing shows up...

Still searching.
Hi. The easiest is definitely a shell-script to invoke your denoiser of choice. The problem you have, is that the parameters for the denoising are most likely not the same for all 166 files.

Noise is most noticable in the space between notes. In loud passagesm the noise is not heard, unless it is an actual hum. One approach is therefore to get rid of the noise in the spaces. I have had luck using an expander-plugin as a noise gate to great effect. With the right settings I could remove virtually all noise between notes, with absolutely minimal impact on the notes themselves.
An expander is like a reverse compressor, but operating below instead of above the threshold. So silent, but noisy passages can be expanded into dead silent passages.

If you have a hum note, then you could try to kill it with a couple of ultra-narrow parametric EQ. If the hum is a sine wave, just one band should kill it, but that is rarely the case. So if the hum is at 50Hz (as it always is in Europe), a series of super narrow bands at its harmonics, say 50Hz, 100Hz and 150Hz, would kill most of the hum. Theoretically at least.

/Frank
Vox, Selmer, Yamaha and Leslie amplifiers. Rickenbacker, Epiphone, Ibanez, Washburn, Segovia, Yamaha and Fender guitars. Hammond, Moog, Roland, Korg, Yamaha, Crumar, Ensoniq and Mellotron keyboards. Xubuntu+KXStudio recording setup.

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AlexTheBassist
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Re: Batch denoising of an Ardour session

Post by AlexTheBassist »

Frank Carvalho wrote:a series of super narrow bands at its harmonics, say 50Hz, 100Hz and 150Hz, would kill most of the hum. Theoretically at least.
You're right that this helps to get rid of that 50 Hz buzz, but it will never be 150 Hz since going octave up means doubling the original frequency. So this should be 50, 100, 200, 400, 800, 1600, 3200, 6400 and 12800 Hz, respectively. Also, instruments'/mics' resonant frequencies and some kinds of "natural" noises (like that saturation hum around 2.5 and 5 kHz which is usually found on heavily distorted electric guitars) are also removable by parametric. Also, highpass and notch filters can remove some mud and boom when used with care and knowledge. I usually use Calf 12 Band Equalizer from git in order to have parametrics, spectrum analyser and highpass/lowpass in one plugin.
Being creative does not imply being lazy, stupid, or illiterate.

Working in Harrison Mixbus and Ardour on KDE Neon + KXStudio.

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