[Ardour-Users] Important test:

Geoff Beasley songshop at bizmedia.com.au
Fri Sep 14 21:04:05 PDT 2007

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)

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.

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.

Traverso doesn't get them using the alsa driver. This may or may not be 
significant. Jack is the standard way of connection here,in collaboration 
with Qjackctl, so a test with jack is what I most seek. Tone is the best way 
to test audio stability; i wonder how many people have tested with tone ? I 
hadn't for some years; when i did i was shocked at the result.
any feedback will be most welcome


HW: tried 32 bit Amd, 64 bit Amd, 64 bit Dual Core Amd, CCRMA, 64 Studio, 
Musix, Gentoo, alsa 1.0.13 thru 15 rc1, Jack 103,107x, Jackdmp,Ardour 2.5, 
Ardour 99.3, kernel 2.6.18,20,21,22 all the major RT,with/without 
SMP,posix,RT,vst support; have i forgotten anything ? probably. but you can 
bet I've tried it.

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