[LAD] [Ardour-Users] TAP EQ issues, revisited

Mike Taht mike.taht at gmail.com
Sun Aug 5 03:21:58 UTC 2007

I completely rewrote tap eq while on vacation last month to be pure sse2,
using doubles for extra resolution, with no denormal problems, and, at least
on x86_64, far greater speed, especially for the stereo version. The changes
were so extensive as to require a new plugin number, which these have. I'm
not settled on  the name, but...

See http://www.taht.net/~mtaht/ <http://www.taht.net/%7Em>mdp.tgz for a

I have tested extensively on my own machine but have not cleaned up the code
enough to justify a formal release, perhaps our efforts can be synced....

On 8/4/07, Steven Chamberlain <steven at pyro.eu.org> wrote:
> Hi,
> There was a thread on LAD two years ago, almost exactly, pointing out
> the denormal problems in TAP's EQ plugins:
> http://linuxaudio.org/pipermail/linux-audio-dev/2005-August/013367.html
> Unfortunately the problem was never fixed.  Many people are still having
> issues with 'TAP Equalizer' and 'TAP Equalizer/BW', as there are recent
> posts in ardour-users regarding spiralling CPU usage for DSP.
> I've been doing my best to debug and fix the problem, but now that I
> actually want to reproduce the problem, I can't!  I can't reproduce the
> jump in CPU usage, although I suffer a loss of audio in Ardour when I
> have many TAP EQ's running in a session.
> So, I tried a few small changes to tap-plugins-0.7.0 which seemed to fix
> the loss of audio.  If anyone can reliably reproduce the jump in CPU
> usage (which usually triggered by periods of silence in the middle of a
> recording), then please try rebuilding the TAP plugins from source, with
> and without my attached patch, and see if it helps.
> Please note, if your current tap_eq.so and tap_eqbw.so are already
> installed in /usr/lib/ladspa/, you may need to edit the Makefile and
> remove "local/" from the .so and .rdf install paths.
> I'm hopeful that this might cure denormal problems that some people have
> suffered from with these plugins for years.  If this works, I will test
> many more plugins for the same problem and perhaps fix those, too.
> Thanks!
> --
> Steven Chamberlain
> steven at pyro.eu.org
> _______________________________________________
> Linux-audio-dev mailing list
> Linux-audio-dev at lists.linuxaudio.org
> http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-dev

Michael David Taht
PostCards From the Bleeding Edge
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