Subject: Re: [linux-audio-dev] Moog VCF in SpiralSynthModular
From: Mike Rawes (mike_rawes_AT_yahoo.co.uk)
Date: Fri May 24 2002 - 19:46:15 EEST
On Fri, 24 May 2002 10:15:45 -0400
Paul Davis <pbd_AT_op.net> wrote:
> >> You mean dynamic resonance control at _audio_ rate ? I would assume
> >> that being able to feed envelopes and LFO up to perhaps 10 Hz is
> >> sufficient for the resonance port ?
> >
> >You can get some fantasic effects modulating cutoff at near audio
> >rate or above :)
>
> the problem is that a LADSPA host has no way of knowing that an audio
> port will be used for control. Ardour, for example, will count all
> audio ports as contributing toward the total inputs for the plugin.
>
Sometimes it is useful to consider an audio input a 'control'. For
example, the _audio_ output from a sinewave, DC shifted and scaled
appropriately, can be used to _control_ the cutoff frequency of a
filter. This implies that this cutoff frequency input is a "control"
input (in a semantic sense) of type LADSPA_PORT_AUDIO!
> LADSPA currently makes audio+control ports orthogonal to each other. i
> don't think there are any LADSPA hosts at this time that allow the
> user to connect the ports "by hand" ...
'modular synth' type hosts such as SpiralSynthModular and
ALSAModularSynth allow, nay, require this to operate.
Maybe we should consider a rethink on the meaning of LADSPA port types,
as clearly it is not the case that a LADSPA_PORT_AUDIO type port will
always recieve what is considered 'audio' data?
-- Myk_________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com
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