[linux-audio-dev] LADSPA and Softsynths

Richard Furse rf015d9821 at blueyonder.co.uk
Tue Dec 10 14:18:00 UTC 2002


Just an observation about an alternative path on softsynths: a LADSPA plugin
or network can be used easily enough as a softsynth using control-voltage
(CV) approaches (a few already exist). It's just a matter of agreeing the
conventions - implementation is trivial.

I've been meaning to finish writing PNet for a while (I've mentioned it a
few times) - essentially an environment where LADSPA plugins are strung
together to form a "patch" and are wired up to "standard" CV controls for
pitch, velocity, MIDI CC etc. These CV components and outputs can be
provided by the host as "fake" plugins providing the CV signals based on
MIDI input (or by using a non-LADSPA convention). This is trivial to
implement and provides an extremely flexible way to build plugin-based
softsynths from LADSPA components - or to wire existing self-contained
LADSPA soft synths (e.g. the "analogue" synth by David Bartold in the CMT
library, see http://www.ladspa.org/cmt/plugins.html) up to MIDI streams.

All a question of time - if anyone wants to do the rest of the
implementation then please let me know. The code required to do the above
also provides a nice way to store patches of plugins for standard processing
chains. Patches would probably be stored as XML representations of
pure-LADSPA networks. BTW, is anyone doing this already? If so, 50% of the
code is already done. ;-) I'm thinking in terms of defining a synth using
two patches - one to define the per-note network required (e.g.
CV->osc->filter->OUT) and another for any per-instrument post processing
(e.g. IN->chorus->reverb->OUT).

--Richard





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