Sound distortion in Windows XP

September 3, 2005 2:31 PM

Sound distortion on Windows XP

I have noticed that if I am downloading or uploading at high speeds and when I am burning CD's/DVD's my sound gets very choppy and distorted.

What causes this and can I prevent it?

CPU Stats:

Dell 3.4ghz Pentium 4 HT
1Gb SdRAM
250GB Hard Drive
Windows XP Media Center Edition
Service Pack 2

posted by chiababe to computers & internet (11 comments total)

Enable DMA on your drives.
posted by devilsbrigade at 3:03 PM on September 3, 2005

Is it a built-in soundcard or a daughter-board? Where is the source of your music (which hard drive) and which hard drive are you up/downloading/burning from/to/from?

It's possible that the other functions have higher priority over accessing the drive than the music/sound program that's accessing the drive.

Possible solutions - try defragmenting the hard drive or try using a different media player (ie., Winamp, try with version 2 - it's very very resource-light).
posted by PurplePorpoise at 3:05 PM on September 3, 2005

(sorry for the abrupt answer)
If disk access (both CD & HD) has to go through memory/caches, it has to go through the CPU at least twice to be useful. This massively slows stuff down, especially pushing stuff to different devices, because the entire CPU is being taken up just shuffling data through.

Most modern mid-upper-end motherboards support some sort of DMA. Sometimes, its a driver issue. The mobo that I use now "just has it," and the last machine that I had to deal with this with was quite old, so I can't give you specifics other than that.
posted by devilsbrigade at 3:09 PM on September 3, 2005

(and because I suck...)
DMA = Direct memory access. Its a way for devices to get data to/from eachother without going through the CPU.

I found a few links that might help:

For Harddrives
For CD drives
posted by devilsbrigade at 3:12 PM on September 3, 2005

(devilsbrigade) I have the DMA already activated. That was a good tip though.

(PurplePorpoise) The media files that I am playing are loacted on the same drive as the one I am transfering to and from.

I have never had this problem with other computers before so it has me puzzled.

I have tried MediaPlayer, Itunes, and realplayer with the same results each time.

Gets anoying when I want to listen to music and download a file from a torrent or something.
posted by chiababe at 3:36 PM on September 3, 2005

The "cpu being too busy" argument doesn't hold water. MP3 players decode whole chunks of the song at a time, so that they do not require constant CPU attention. They play these buffers through DMA with the soundcard, so that very little CPU is needed. Unlike hard drives, it's not possible to disable this use of DMA.

Anyway, I have found that when there is a lot of activity on the bus, that this generates a lot of electrical noise which leaks into the sound card. I think this is why most people that use their PC as a recording studio get an external DAC/ADC unit. Try looking for an "external sound card" (though it's not a card anymore) that has a USB interface. It should have its own powersupply and analog section isolated from the very (electricallty) noisy PC case, and only communicate digitally with the PC.
posted by Rhomboid at 4:03 PM on September 3, 2005

What kind of distortion are you talking about? Pauses, stutters, clicks, & pops or is the tone actually fluctuating?

I've never been a fan of WMP or RealPlayer (haven't had 1st hand experience with iTunes). Try the latest 2.x version of WinAmp from here.

In light of the other responses, I'm thinking that Rhomboid might have a potential cause for the problems. What sound card is it?

Alternatively, it's possible that there's something else hogging up CPU/memory. What's your CPU, PageFile, and Physical Memory useage when you have the distortions (do a ctrl-alt-del, goto the performance tab)?

Rhomboid - would an onboard soundcard vs. a daughterboard soundcard make a difference? If it's a daughterboard, would moving it to a different slot (just to change it position relative to the electrical interference) help?
posted by PurplePorpoise at 7:57 PM on September 3, 2005

I don't know. By daughterboard I assume you mean a standard PCI card? I have a PCI soundblaster card, and I have noticed that during heavy disk I/O (such as defragmenting or copying large files) I can hear pops and distortion in the sound output. It's certainly caused by the IO because if I stop the disk activity the noise goes away.

The cpu utilization is close to nil (certainly less than 20%) so it's not a lack of CPU power. I have always assumed that it's just all the noise generated from all that bus activity. The inside of a computer case is generally an extremely bad place for analog electronics.
posted by Rhomboid at 9:10 PM on September 4, 2005

A dart in the dark... my sound card on my recently-built MB has a "bass-boost" visible in the typical volume control. When disabled, it solved all of my weird sound problems.
posted by OneOliveShort at 12:10 AM on September 5, 2005

Hmm, yeah, it does sound like radio interference. Yes, daughterboard = PCI card. I'm not sure what you can do to eliminate it. Things that *I* would try, in this order

- if there's a mic, unplug it or mute it through software; while you're there, see if there's anything in the control panel that's enabled (such as the bass boost/asist that OneOliveShort mentions) that doesn't necessarily have to be
- if there's a SPIF/D (or whatever it's called) running from the soundcard to the CD drive, maybe remove it completely
- if you have free PCI slots, try putting it into a different slot (with WinXP these days, you don't have to worry about IRQ/DMA conflicts like motherboards of yore)

Good luck
posted by PurplePorpoise at 9:19 AM on September 5, 2005

Had a similar thing happen to me after replacing my modem following a power surge which had knocked out the old one. Suddenly, stutters/crackling, etc. in the audio whenever the modem dialed, or when internet usage was heavy. I tried most of the things mentioned, with no effect.

Being a bit of a home recordist, I went and bought me the new soundcard I'd been intending to buy. Now, the modem still grabs the old soundcard, but since I'm using the new one, all is well, sonically. I'm sure a move to a modem with better-written drivers would've accomplished this as well.
posted by DrAwkward at 5:41 PM on September 10, 2005