With every soundcard I have had to run in my system, I would hear an occasional buzz when playing music. I tried a lot on the software side, using Directsound/Waveout/Kernelstreaming with all sizes of buffers. I then concluded my PSU needed replacement - it's only 230W rated - so I started saving up for a new one.

Now recently, when I was evaluating Hardware Mixing and bit-perfect SPDIF out, I noticed that the dropouts occur in digital loops too! Here's what it looks like:


Playing digital silence


Playing a sine in the right channel

The weird thing is, it is only the right channel that is affected about 80% of the time. Then how could it be a stream buffering problem or a PSU problem? That should affect both channels, or?

Your wisdom is much appreciated

Edit: jpg changed to gif for faster download - sorry. What was I thinking?!

Maybe some PCI/shared interruptions problem?

Well it's not a PCI slot sharing an int on the mobo (it is, but I left the other slot empty). In Windows, there are an agp card, a nic, an ide controller and a usb controller on the same IRQ though... I'll see if I can fix that. Thanks for hinting to it.
It still puzzles me why the right channel is more often affected.

edit: I can't change the IRQ assignment I'm afraid... I'll try disabling some devices.

As KikeG mentioned, it's possibly an interrupt problem.

- which version of win$$$ are you running ?
- what kind of mainboard do you have ?
- do you have the latest drivers&bios ?
- any bus overclocking ?
- any big fan (or even cell phone) near the sound card ?
- any other os you can try at the moment ?

edit: any high-priority tasks running in the background ? think Zonealarm, anti-virus, "windows rambooster snake-oil edition" ?...

Hi,

-I'm using Win 2000 SP3
-mainboard is an Asus CUBX (440BX chip)
-yes, latest stable BIOS
-no bus overclocking, but I am running a pin-tricked Tualatin Celeron. However, it is running at standard speed and voltage.
-it is in the lowest PCI slot, no components in the 2 slots above it. The only fan is in the PSU.
-I have Knoppix laying around, otherwise my hdd is such a mess at this moment that I can't free space for an OS install.
-Yes, I have Zonealarm and Mcafee running - I'll try without them.

Windows ignores the IRQ I set for the soundcard in the BIOS. I guess I can only fix that by disabling ACPI, but that's not an option - I'd have to reinstall all software and stuff.

"spread spectrum"
will this be the cause?
is it enabled?

EDIT: I don't think 230 W PSU is the fault
Coz if the PSU has problem, your computer will reset for no reason or become unstable.

I have a friend that overclocked his Athlon XP Barton 1.8 GHZ to 2.4GHz
Mobo : Asus (unknown model, but he told me the chipset is nForce)
RAM : 512MB at 333MHz
HDD1 : WDC 80GB (model=unknown)
HDD2 : WDC400EB 40GB
DVDROM1: Samsung 16X
CDRW2: TDK VeloCD 48X24X48X
VGA Card : Leadtek Geforce 4 MX 440

not even after a month, his PSU burnt.
Mobo burnt
Both WDC HDD were burnt too
luckily his DVD/cdrw drive, RAM is still ok

LOL

@Kotrtim: that wouldn't explain why it occurs in digital loops, or?

For the rest, I tried
-closing all programs/services I could, including ZoneAlarm and McAfee. Didn't help.
-toring out my ethernet card and udma 66 controller. Didn't help.
-replacing win2k ACPI HAL with standard pc settings. Didn't help.

Now I've got a pc that doesn't shut down by itself and yet sound skips
Any more ideas please?

I'm not that knowledgable about motherboards, so I don't know if yours uses VIA chips? If it does, what version of the 4in1 drivers do you run, and have you downloaded the separate sound-chip drivers?

I had a bunch of problems with onboard sound, kind of like the huge pops on your first graph - and loads of tones present when resampling.. Drivers would either fix problems or cause more, so I found I had to get as many as possible and try them all out

No, it's an intel chipset. I always thought the 440BX was the most robust ever made, so I needed to have one (I was a chipset maniac at the time, like I am a soundcard maniac these days ). I went through lots of hassle to get this motherboard - imported it from Germany.
So... don't tell me the motherboard is flawed!!!! (Kidding ).

Upon further evaluation - it does seem that getting rid of ACPI has helped in getting down the number of drop-outs. So probably it is indeed a buffer underrun problem. With all programs/services shut down, there are only two pops in a minute now.

Do you think a newer motherboard (with a newer southbridge and PCI design) will help? I really don't want to part from my CUBX :'(

Have you already tried Intel drivers or BIOS update?

Have you tried moving the card to another slot to change IRQ assignments? Some bios'es have options to e.g. disable unneeded recources like 2nd serial port and assign free IRQs to PCI devices/slots or similar ...

I had similar problems before with onboard sound. (can't tell if it's exactly the same as I don't have digital out - I only know how it sounded) Moving the network (!) card helped. as Win2K's IRQ assignments were totally changed by this and onboard sound got an un-shared IRQ (while it was shared with 2 other devices before).

BTW: The sine wave image you've posted looks as if the the dropouts consist of small parts of the waveform moved to the left by a few samples. If my logic co-processor works correctly without caffeine right now this means these parts are played back too early/shifted into the future. Anyway - I have no specific idea what this could mean, but maybe someone else knows.

This is probably an idiotic suggestion - but I see you're using Cool Edit. There are plenty of settings to play with in there, and some suggestions on their web site. Try changing these to remove the problem. That won't help with playback from other software, but it might be a start.

Also, try system monitor and/or resource meter (it's in Win9x, but you have to choose to install it - it's on start: programs: accessories: system tools - when it's installed) - see what system activity is co-timed with these problems.

Cheers,
David.

He said he has win2k but still, watching for high cpu (or disk..) usage (using system monitor) is a very wise idea !

Also - for Patsoe - try playing with PCI Latency Timer (if there's one in your BIOS). You'd be surprised what a change it can make.

Cheers

I've tried all slots that don't share interrupts with video/usb. Legacy ports are disabled in BIOS (except PS2). With any configuration, Win2k would set all PCI devices to IRQ9. That's why I disabled ACPI (and it didn't cure the problem...).

Also, it's not just Cool Edit - playback blips with every playback program and several soundcards. Network traffic seems the most important trigger. Ripping the NIC (a 3Com) out didn't solve things though. It just got milder. And besides, this would seem symptom-management to me: I need my NIC

I have never tuned PCI latency timer though. It is set at 32 because I thought it should be low (don't remember why anymore ). I'll try some.

I've seen similar problems being cured by enabling/disabling udma on harddrives / cd drives / etc. (also with different soundcards in same machine)

I've tried PCI latency times of 32, 64 and 128 clockticks. No cure. Is there any way to set individual latencies for devices in win2k? I couldn't find any. It would be convenient though; then I could crank it up for the soundcard and lower it for the NIC.

I'll look at the UDMA modes too, thanks.

Windows and its great wisdom loves to share a single IRQ with as many devices as it can, just because PCI allows it... most of the time leaving many free IRQs unused.

Try disabling plug and play bios if you can, and setting manually irq settings there. You can usually choose a different IRQ per slot. Also from control panel, system, device manager see the card properties and try manually changing IRQ settings. Start with the audio card only. Also disable any unnecesary device from the bios (unused ports, USB, etc) anything that takes an IRQ. Try disabling any power management features. Sometimes its the other way around, and you have to enable power management, but configure so it doesn't save anything or does the least to save energy (don't monitor any irqs, don't turn off anything, etc).

There are some important "tweak" options in the bios you can check enable/disable, for PCI there are things like PCI delayed Transaction (enabled), CPU to PCI Write Buffer (enabled), PCI 2# Access Retry (disabled), PCI Dynamic Bursting (enabled), etc.

Anyway read this and try one by one. It could be long and annoying. Oh yes, do this with the least amount of devices installed, so remove everything else and be prepared to spend some time.

Having the latest BIOS and device drivers already installed could help too.
Lastly, try another card or another motherboard.

Thanks for the BIOS tips. I'm prepared to spend some time, yes.

I've already switched to manual IRQ assignment. It was quite fun to do actually: I removed the ACPI PC driver from the Device Manager and put the Standard PC driver in place (note: first set BIOS to non-PnP OS). Then I rebooted and really expected a wealth of blue screens. But windows started happily, asking me to reinstall some drivers (actually, all drivers I ever installed), and it went on as a non-ACPI PC. But it didn't help a bit...

Well I tried all tips now. All BIOS settings that I could think of, then also disabled some IDE devices, I even tried overclocking the PCI bus to 37MHz.

According to a friend, I really need a better PCI circuit; that is, a newer motherboard. Before I do that, I will try a clean windows install and a new PSU (but the former isn't going to happen this week...).

Thanks for thinking with me!