[PD] [sqosc~]-issues

Roman Haefeli reduzierer at yahoo.de
Mon Mar 26 16:43:25 CEST 2007

On Sun, 2007-03-25 at 21:46 -0400, Martin Peach wrote:
> Chris McCormick wrote:
> > On Sun, Mar 25, 2007 at 07:23:13PM +0200, Roman Haefeli wrote:
> >   
> >> [sqosc~]. it can happen, that after loading the patch, pd is sending
> >> constantly a dc to my soundcard. even when i close pd, the dc stays on
> >> these channels, where pd was connected before over jack. to get rid of
> >>     
> >
> > This happens on my laptop and I am pretty sure it occurs on a hardware
> > level (in my case). The DC is present sometimes after just playing half
> > an mp3 file and then hitting ctrl-C, and definately happens when doing
> > stuff in Pd sometimes.
> >
> >   
> How can you guys tell if there's DC in the signal? I'd love to get a 
> sound card that outputs DC!

hehe, actually i am not sure, if my soundcard physically outputs dc or
if the output is high pass filtered.  maybe i should elaborate a bit
more my setup and what i did in order to explain, why i assume dc on the

i run pd over jackd and jackd runs on the rme card. the hdspmixer has a
levelmeter for each input and output, so i can see the signal-levels
that are sent from jackd to the outputs of the card. 

here the jack-routing:
pd out 1 -> hdsp out 1
pd out 2 -> hdsp out 2

now, when i load the help-patch of [sqosc~], the level-meters of hdsp
out 1 and 2 show full amplitude and i hear a hard click on the
loudspeakers (similar to the sound, when sending dc to the speakers).
when i close the patch, the amplitude remains. when i disconnect pd from
jack, the amplitude goes away and i hear a hard click again. but even if
i restart pd, the amplitude comes immediately again (with the loud
click, of course). also if i connect other softwares over jack to the
hdsp out 1 and 2, the high amplitude comes again. to get rid of that, i
must restart jack. but as soon as i load the help-patch of [sqosc~]
again, i have the same situation again (loud click and full amplitude on
the meters). i don't know of any other setup with that behaviour. this
happens only, when i load a patch with one or more [sqosc~]s. that is
why i assume, it is (at least a bit) related to [sqosc~].


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