[Audacity-devel] multichannel Audacity testing

[Daniel J. <da...@mo...>]

We've done our first night of testing with the Delta 1010, with mixed=20
results. The hardware is:

Asus P4PE motherboard (Intel 845 chipset)
Pentium IV 2.4B (2.4GHz, 533MHz FSB)
Seagate Barracuda IV 80GB
M-Audio Delta 1010 (IRQ 9)
Matrox G550 Dual DVI (IRQ 10)
SB Live (IRQ 11, for soundfonts in hardware with external MIDI=20
keyboard)
All other hardware disabled in BIOS (USB, serial ports, parallel port,=20
onboard sound etc) except for Broadcom onboard LAN sharing IRQ 9 -=20
configured, but disabled for recording session with:

ifconfig eth0 down

cat /proc/interrupts

now shows only Delta 1010 on IRQ 9

Software:

Linux Mandrake 9.1 upgraded from 9.0
Multimedia patched 2.4.21-pre kernel
ReiserFS filesystem on / and /home
ALSA upgraded to 0.92 with Cooker RPMs
envy24control compiled from alsa-tools 0.93 tarball
wxGTK 2.40 compiled from tarball
Audacity 1.1.3 compiled from tarball=20

With the Delta 1010 and two input tracks selected in the Preferences,=20
it all works fine. Four input tracks also works. Select eight input=20
tracks and it works fine initially, but after a while something weird=20
happens to the recorded input - I've never seen this behaviour with=20
Audacity in any other context.=20
 =20
Suddenly the waveform is drawn as a rapid series of the same shape.=20
Playing the track back, it sounds as it looks:

da-da-da-da-da-da-da-da-da-da-da-da-da-da-da-da-da-da-da-da-da-da-da-da-d=
a-

Can anyone replicate this bug, if it is a bug? With full duplex=20
enabled, it was even more flaky. I did compile Audacity before the=20
upgrade to Mandrake 9.1, so this may be related. On another computer=20
with just a normal two-channel soundcard, Audacity can dummy 'record'=20
eight channels in full duplex without problems, but then it isn't=20
actually doing much work.=20

Next, we're going to try Thac's RPMs of Audacity 1.1.3 and at least=20
one other multichannel recorder app to see if this is my lack of=20
compilation skills, a system problem or an Audacity problem.

Cheers

Daniel