[linux-audio-user] Denormal problems with some LADSPA plugins

[tim hall]

On Friday 12 May 2006 20:13, Q was like:
> I'm having denormal problems with some LADSPA plugins, mainly the Triple
> Band Parametric with Shelves, Plate Reverb and Glame High Pass filter
> (which I started to use to replace that function in the Parametric).
> They are really useful plugins but after a short space of time an
> instance of one of them will start racking up thousands of Xruns and
> processor usage climbs inexorably towards 100%.
>
> I occasionally had problems before but it seems a lot worse since I
> moved to DeMuDi 1.3 and the later version of Ardour that ships with it,
> but it's probably just a case of selective memory.
>
> Sampo suggested on the Ardour forum that I should try compiling the SWH
> plugins using SSE instructions -- thanks for that. I got the latest tar
> of the plugs and compiled them using those instructions but
> unfortunately it hasn't cured the problem. Probably I did something
> wrong -- I can't say I fully understood the options in the Readme.
>
> Has anyone any advice on how to cure this problem, or any ideas where I
> might have gone wrong compiling with SSE instructions? Preferably in
> words of one syllable or fewer ;-)
>
> I'm using a Pentium 4 if that makes any difference to anything.

I have had problems with the symptoms you're discussing, using the same set-up 
and the stock demudi kernel (which is very old). I have had much more steady 
CPU and DSP usage since I upgraded and recompiled my kernel to 2.6.16 - I 
have been using the TAP plugins more than the SWH ones you mention. I will 
test them out when I get a spare moment, as the only difference on my system 
is likely to be the kernel and hardware.
-- 
cheers,

tim hall
http://glastonburymusic.org.uk/tim
We are the people We've been waiting for.