[LAU] Convolver?

Fons Adriaensen fons at kokkinizita.net
Fri Dec 14 10:51:16 EST 2007

On Fri, Dec 14, 2007 at 02:06:22PM +0100, Ketil Thorgersen wrote:

> I have been browsing for convolver/impulse respons plugins for linux and 
> have found a few: brutefir, jace, jack-convolve and dssi-convolve. The 
> only ones with guis are the two later ones which is also the simplest, 
> and which seem to be discontinued. I have not tried jace, but brutefir 
> seems to be quite complicated to use. Does anyone know if someone is 
> worling on an easy to use (for a beginner) convolve plugin for linux - 
> preferably as a ladspa plugin??

Like Brutefir, Jace uses a text format config file, but it is somewhat
easier to set up. Jace will be phased out, and replaced by Jconv which
takes the same config files but can be much more efficient if you want
small or zero processing delay.

There will be a new release of Jconv probably next week. The convolution
engine now has been factored out into a separate shared library with a
clean API, and that will also be the core of Aella. This is a JACK app
with a GUI, and optimised for reverb.

The work required to finish Aella (which has been in development for
a long time) is not related to the convolution code, but to the need
to simplify the rather complex configuration that is required to use
some impulse responses.

The IRs that are available on the web are all in different formats,
and they all need some preprocessing in order to be used: finding
the exact position of the direct sound and removing it (to be mixed
in separately), separating the early reflections and the reverb tail,
amplitude normalisation, additional delays, cleaning up noisy reverb
tails, equalisation, resampling, etc. 

All of this should be done off-line, with a 'standardised' IR file as
the result, otherwise Aella, even with a GUI, would be as difficult to 
use as a basic convolution engine like Jconv. And even after all that
preprocessing, some 'metadata' needs to be preserved to enable efficient
multichannel use, and also in order to allow the user to modify the
reverbs (within some limits) in Aella.

Since it would be impossible for me to copy all available IRs on my
own website (both for copyright reasons, and because it takes a lot
of space), the way I'll try to organise this is to provide scripts
that perform the required preprocessing on the raw files downloaded
by the end user.


Laboratorio di Acustica ed Elettroacustica
Parma, Italia

Lascia la spina, cogli la rosa.

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