[LAD] Another call for brave testers: new Guitarix LADSPA plugins

Andreas Degert andreas.degert at googlemail.com
Sun Nov 27 18:22:16 UTC 2011

2011/11/26 Tim E. Real <termtech at rogers.com>:
> On November 26, 2011 12:40:01 AM Andreas Degert wrote:
>> Hi,
>> we'd like to ask those who are interested in the new Guitarix LADSPA
>> plugins to run them on their systems and give us some feedback. They
>> do fine on our own machines and seem to be fit for wider testing.
>> The plugins "Guitarix Amp" and "Guitarix Stereo Fx" wrap all of the
>> entire sound engine of Guitarix. You can load a preset that you defined
>> with the Guitarix program, and even define some parameters for DAW
>> automation.
>> It's explained in our wiki:
>> https://sourceforge.net/apps/mediawiki/guitarix/index.php?title=How_to_use_t
>> he_new_ladspa_plugins
>> Our SVN:
>> svn co http://guitarix.svn.sourceforge.net/svnroot/guitarix/trunk guitarix
>> After checkout, build with
>> ./waf configure && ./waf && sudo ./waf install
>> for an installation to /usr/local.
>> Our tracker:
>> http://sourceforge.net/tracker/?group_id=236234
>> Your feedback will be welcome here or there or anywhere..
>> Or in our forum:
>> http://sourceforge.net/apps/phpbb/guitarix/
>> so please, don't be shy and tell us your test results or
>> if you think the concept is usable / unusable :-)
>> ciao
>> Andreas
> Thanks. This is awesome news! Will test.
> I was actually trying to do the very same thing here!
> Creating individual GX Head Amp LADSPA plugins is super easy,
>  like '12AX7' for example. Faust makes it easy.

Yes, but I'm not sure how useful single modules are if you
want to have an amp, and the sound is defined by multiple
components which are tuned relative to each other.

Of course it could make sense to make plugins from single
effects, but it could be a problem that ladspa plugins are not
expected to change and we don't want to make that sort of
guarantee for our effect units.

> But combining them all in one plugin, or even just combining
>  them all in one .so file was very difficult.
> I had some success, but some serious drawbacks.

btw. the guitarix developer list on sourceforge is a good place to
discuss such things :-)

> And then there's the GX cabinets, which I would have needed
>  to extract from GX and make plugins from.

yes, much more difficult because of the sophisticated algorithm for

> Faust is nice, very powerful, makes it easy, but does make some 'automated'
>  aspects hard.
> This is great news because having the GX Head sound in LADSPA form
>  means having no round-trip latency from using GX externally.

but instead of round-trip latency you have latency from buffering in the
LADSPA plugin. The problem is the convolution, the algorithm needs
fixed block size and LADSPA doesn't guarantee that. So we need
buffering, which introduces latency N-1 for buffersize N. But since we
announce that additional latency on the "latency" output port, Ardour
can compensate for it (of course not for realtime monitoring). If you
don't need any of the convolution units, you can switch off buffering,
or you can make it small (64 samples or even down to 16) if you have
tight automation points from your DAW.

> PS. I actually fixed the existing Guitarix Distortion plugin by
>  composing my own .dsp file (the original has long since been missing)
>  and compiling.
> It proved that the 'Drive Level' control was indeed broken in the existing
>  .cc file. Yet, it was still disappointing after all that work, it doesn't
>  really help the sound much.

yes.. sorry that you put time into it... I think it doesn't make a lot of
sense any more to work on the old plugins.


More information about the Linux-audio-dev mailing list