[Asterisk-Users] odd 'digital' sound artifacts

[Gerard Saraber]

Hi,
I've got some weird sound artifacts happening during calls, they're very
hard to describe, so I have a 122kb recording:
http://openprojects.rarcoa.com/~miztic/artifact.wav
normally the artifacts are just short blips, not quite as long as the
one above, but they sound the same.
When using the aggressive echo suppressor, it seems like those artifacts
cause a really loud buzzing sound to come out of the cisco phone, pretty
much made using the aggressive canceler impossible to use, it's too bad
because it worked the best out of all of them, mark3 works ok but still
gives echos on at least 20% of the calls.

I thought they might be caused by IRQ sharing, so I pulled one of the
TDM400P cards out and made sure the remaining two were on their own IRQ,
the artifacts were still there. I've also tried running a kernel with
all the low-latency stuff turned on, and the same kernel with it all
turned off (2.6.16-rc2) doesn't appear to make any difference either.
I'm not sure what else to try, any input would be appreciated.

Thanks,
Gerard Saraber
gsaraber at rarcoa.com

hardware:
AMD64 1.8Ghz 512M ram
MSI nforce3 socket 754 mainboard
3 Digium TDM400P cards, 10 FXO + 2 FXS modules

/proc/interrupts
           CPU0       
  0:    2784232    IO-APIC-edge  timer
  1:          8    IO-APIC-edge  i8042
  8:          0    IO-APIC-edge  rtc
  9:          0   IO-APIC-level  acpi
177:      71552   IO-APIC-level  eth0
185:       9412   IO-APIC-level  libata, NVidia CK8S
193:          0   IO-APIC-level  ehci_hcd:usb1
201:          0   IO-APIC-level  ohci_hcd:usb2
209:          0   IO-APIC-level  ohci_hcd:usb3
217:    5577811   IO-APIC-level  wctdm, wctdm
225:    2769262   IO-APIC-level  wctdm

lspci (for completeness):

02:07.0 Network controller: Tiger Jet Network Inc. Tiger3XX Modem/ISDN
interface
        Subsystem: Unknown device b119:0001
        Flags: bus master, medium devsel, latency 32, IRQ 217
        I/O ports at ac00 [size=256]
        Memory at fdeff000 (32-bit, non-prefetchable) [size=4K]
        Capabilities: [40] Power Management version 2

02:09.0 Network controller: Tiger Jet Network Inc. Tiger3XX Modem/ISDN
interface
        Subsystem: Unknown device b119:0001
        Flags: bus master, medium devsel, latency 32, IRQ 225
        I/O ports at a800 [size=256]
        Memory at fdefe000 (32-bit, non-prefetchable) [size=4K]
        Capabilities: [40] Power Management version 2

02:0a.0 Network controller: Tiger Jet Network Inc. Tiger3XX Modem/ISDN
interface
        Subsystem: Unknown device b119:0001
        Flags: bus master, medium devsel, latency 32, IRQ 217
        I/O ports at a400 [size=256]
        Memory at fdefd000 (32-bit, non-prefetchable) [size=4K]
        Capabilities: [40] Power Management version 2


-- 
Regards,
Gerard Saraber
Network Admin, Rarcoa, Inc.
(630) 654-2580 x11
gsaraber at rarcoa.com