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Forums     Discussions     Announces, Releases and Discussions Dynamic convolution? Possible?

Is it possible to create a dynamic convolution-plugin?

Currently we have static convolution-plugins (such as the cabinet-simulator in Boogex, or Pristine Space)

But rather than having static impulse-response files, is it technically possible/sensible to have dynamic impulse-response files? (in a new plugin)

Not as a reverb, but as a coloring tool (to make a digital sterile sound feel more alive)

For example, recording white or brown noise (through our real room location or cabinet) for as long as we need (at least as long as the sound we want to color with this IR) and then play this IR in the new dynamic convolution plugin along our dry sound (perhaps route it into the plugin from a track in a DAW, so that it always plays in sync with the other tracks)

So basically, instead of using a normal static IR, this new plugin reads the dynamic IR progressively as the song plays along and therefore performs a continually changing convolution to the dry sound (the continuous subtle change to the white or brown noise that we recorded in the real room)

If it is not really possible (if it won't produce usable sound), could it perhaps just become a kind of dynamic EQ? (Like CurveEQ matching EQs on the fly rather than by 2 static snapshots)

It's just an open thought, but I would love to see a working Voxengo plugin along these lines :)



My platform: Win7 home premium x64 // I use Voxengo 32bit & 64bit VST plugs in Reaper 5.x 32bit and 64bit

This is possible, both via harmonic-enhancement like dynamic convolution (so called diagonal Volterra kernels) and via time-varying convolution (via crossfading).  However, I have no plans to produce such tool at this moment.  I suggest you to search for such plugin on the web.

Well, the 'usual suspects' don't seem to have plugins/tools like this in their arsenal, but I will look deeper and see if something turns up.

Thanks for taking time to reply :)


My platform: Win7 home premium x64 // I use Voxengo 32bit & 64bit VST plugs in Reaper 5.x 32bit and 64bit

A follow-up, in case somebody else should be interested :)

I searched as broadly as I could and found only one single VST-plugin that does what I was looking for.

Unfortunately it is experimental so mono only and it has a minor gui-problem in Reaper (the reverb-type selector on the gui resets when the window loses focus, although the actual chosen reverb isn't reset) and crashed once when I tried running multiple instances of it (although it is possible to do it if it's treated gently)

However, it is the only plugin I could find that creates movement to 'static' audio (which makes it much more pleasant to listen to, in my opinion)

I ran a sine-wave into the plugin and looked at the result in Voxengo's Span.

-Without the plugin the sine-wave was 'static' (no movement, just a tone)

-With the plugin the sine-wave was full of dynamic harmonics (not just static harmonics as is all I could get out of the free Acustica-Audio plugins I tried) and more or less subtle volume-changes (precisely what I was looking for to liven up otherwise sterile VSTi synth-tracks)

I used these settings:

mix level: 100

reverb time: 0.2 s

pre delay: 1ms

late-delay: 1ms

method: cont. varying

noise type: sparse

The plugin date is march 2010, so I'm quite puzzled nobody has taken this technology further (at least to my knowledge nobody has)

If anybody wants to experiment with this, or read more about the tech-stuff, here's the link:

"The Switched Convolution Reverberator"

(presented at the 127th AES Convention)

By Keun Sup Lee, Jonathan S.  Abel, Vesa Valimaki, Tim Stilson and David P.  Berners

Here is what they say about it themselves:

"The Switched Convolution Reverberator is an artificial reverberator having low memory requirements and small computational cost.  The reverberator consists of an equalized comb filter driving a convolution with a short noise sequence.  The reverberator equalization and decay rate are controlled by low-order IIR filters, and the echo density is that of the noise sequence.  To reduce an unwanted periodicity at the comb filter delay length due to a repetition of noise sequences, the noise sequence is regularly updated or “switched.” In this way, this structure is efficient and readily generates high echo densities.  Several structures for updating the noise sequence, including a leaky integrator sensitive to the signal crest factor, and a multi-band architecture, are described."

My platform: Win7 home premium x64 // I use Voxengo 32bit & 64bit VST plugs in Reaper 5.x 32bit and 64bit

Thank you for information.
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