[LAU] Important test:

[Wolfgang Woehl]

Samstag, 15. September 2007 Geoff Beasley:
> Folks,  I am on something of a quest here. I have been suffering clicks in
> the audio stream here for sometime now.  I have changed my audio HW from 3
> x ice1712 cards to a Firepod firewire, changed my Distro 3 times, changed
> everything I know about kernels, jack, alsa etc etc...; all to no avail.
> The click manifests when duplex recording from ardour back into ardour  (
> or traverso, mhwaveedit etc... this is not ardour specific)

Geoff, I'd be surprised if anyone could be helpful without knowing what 
versions you run (jackd, ardour, kernel etc.), how your access to realtime 
capabilities is set up, what your jackd invocation looks like etc.

> So what I would like to ask is can others please carry out this simple
> test. Record some tone first. (you could just install  Jaaa.) Generate 20
> minutes of tone into 4 Ardour (or whatever) tracks. Then playback the tone
> whilst recording it back into another 4 tracks in Ardour.

I can't believe I actually did this. 20 minutes sine tone out of jaaa into 4 
ardour tracks and then another pass with 4 tracks recording from the first 4: 
No clicks, no glitches. And I'll be hearing 300hz for the rest of the week. 
This must be Dick Cheney's idea of Good Clean Fun.

Versions here are contemporary: Ardour/GTK 2.0.5 (built using 2234 and GCC 
version 4.2.1) and jackd 0.103.0 and opensuse 2.6.22.3-7-bigsmp kernel with 
CONFIG_PREEMPT_VOLUNTARY, mind you. I haven't encountered your problems with 
different hardware and former versions either.

> Do you see any clicks ? They sound exactly like changing an I/O point
> within ardour when program material is being played back.. They appear as a
> spike in the waveform. On closer inspection I generally see a "flat-line"
> between a broken waveform of about 70-110 samples. Sometimes it's smaller,
> and sometimes it just a typical "distrotion" of the wave itself. I always
> get them. Sometimes it goes for 3-4 minutes without one, but I always get
> them.

I suspect your board and/or an interrupt issue. Just a hunch.

Wolfgang