With sage guidance from PA, I was able to concoct a patch that uses the FluCoMa tools and the Huddersfield Impulse Response Toolbox for automatic spectral compensation.
The material that I’ve been working with lately is full off fairly egregious high frequencies and I wanted a way of finding the bands which are problematic and attenuating them with a simple interface. Using fluid.bufmelbands~ to extract a set of frequencies and amplitudes, I produce an inverted impulse response that, in theory, represents a quasi a sonic negative-image. I then convolve the original sound with this signal using multiconvolve~ to get a real-time complex filter on the source audio.
Attached is the max patch as a maxzip/project.
http://boogiebox-nextcloud.cloud.seedboxes.cc/s/DfEtcjAbz2o9bNg
Again, thanks to @tremblap for seeding the idea and giving me expert advice
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Nice! And @rodrigo.constanzo -grade tidy patching too!
Is the idea of using mel bands, rather than just fft bins followed by more aggressive smoothing that the former will be more perceptual-y? How do the results you get here sound compared to what you’d do manually with an EQ?
I have editorial issues with ‘fairly egregious’ ;-p
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Yes, the idea is that the spacing of the mel bands better approximates and therefore creates an IR that that will be useful for removing the things we perceive (opposed to the FFT which is equally spaced). The smooething gives you an extra parameter to nudge the filter where it needs to go. Sometimes I want something more general without going into a territory where the bands are completely obliterated at -90db and so smoothing then backing off on the attenuation works to soften the high freq’s without affecting everything else as much.
I was expected this tool to be much worse than what I can do with an EQ manually but I’m pleasantly surprised. I’ve been using a pretty generic biquad in Reaper to get rid of the frequencies I can see being problematic but it takes ages and I have to work gesture by gesture. Doing it this way is a lot faster and I think it works well enough to replace something like a tilt filter, which I have been layering with the more acute biquads.
is it the oxymoronic nature of that statement or have you been exposed to worse high freq material?
P.S
I have made some extra changes that allow you to change the phase of the filter too! I just have to sort out some errors I’m being thrown by iruser~ before I push it.
Super interesting. Thanks for sharing.
One question: what does the normalize subpath do? Min and max are set to zero.
This is quite cool!
I really need to get back on that ‘spectral compensation’ kick from when we meet and geeked last. I’ve not look at it since posting it on the “secret” forum (where it died a quiet death!), but from what I remember, there was some weird funny business that appeared to be more of a bug than a feature.
The patching is indeed super tidy 
One tiny suggestion though, is you can implement @a.harker’s clever mousefilter subpatch from his Convolution Reverb patch:
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Right now your smoothing and attenuation dials choke when you adjust them cuz they are trying to compute-compute-compute-compute etc…
Oh, is there any reason why the attenuation doesn’t have negative values? (i.e. boosting the egregious frequencies)
The sub patch just takes a list of values and normalises them between 0 and 1. I init to 0. so it works with floats (I think)…
Yeah I wanted to make something like that with mousestate but I just dealt with the lag because I wasn’t changing it much. Let me chuck this in there and update so you can change the phase…
Also I like the fluid visualisation but it’s not really viable across many CPU’s
Okay, more updated version here:
https://boogiebox-nextcloud.cloud.seedboxes.cc/s/rZQFXxM6y7a8eBr
The only thing it doesn’t have now @rodrigo.constanzo is a booster - I can’t figure out how PA changed my normalisation in db’s but when I do I’ll add it.
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