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Old 2005-01-03, 11:22 AM
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oldbrokentapes oldbrokentapes is offline
Join Date: Nov 2004
Weird playback problem

Right, my ongoing inability to concentrate on journals about management accounting, the environment and sustainability has lead me to finally bother typing this out in the hope that some of you fine people can help.

The problem, simplified: stereo playback periodically switches to mono for no discernable reason.

The problem, expanded: this mono playback sounds as though it's like the "central channel" - stuff that is wide left or right disappears, and what plays is what is found near-equally in both channels. However, it's hard to be sure if this perception is correct. At one point I decided that it was just the left channel moving over but then I changed my mind. There is volume loss, but that makes sense, and there may also be some frequency-range loss, but I can't be sure - could just be because particular frequencies are split widely and so vanish.

My system (ahem, blush, etc): eMachines desktop, WinXP Home, year and a half old, 2.3GHz Intel Celeron processor, 256MB RAM, 80GB sensibly defragmented hard drive typically half-to-two-thirds full, Genius PCI soundcard (cheap yes, but very low noise analogue input).

I am aware that the soundcard's drivers are not fully suited to XP, but am fairly confident that this is not the problem as per the following and as per the fact that it's often perfectly functional. Anyway, in no particular order, the following paramaters apply:
  • The problem occurs with all relevant media filetypes - flac, shn, wave, mp3 - though with slightly different results (see below).
  • I have experienced the problem using all relevant playback software (foobar, Winamp, Goldwave, CDWave etc) EXCEPT Windows Media Player (though obviously I haven't been able to test shn/flac in WMP).
  • It occurs when playing media off all relevant hardware - hard drive, audio CDs, data DVDs. My Samsung SM-348B CDRW/DVD drive is a lot more prone to the problem than my Pioneer DVR-106D DVDRW drive or my hard drive.
  • I've been unable to specify the cause as either CPU-intensive or hard-drive use intensive, as it is possible to be working these hard without troubling playback. A sure fire way to induce a major burst of the problem is to extract an audio CD - during extraction, any currently playing media file will jump to mono and back frequently and rapidly.
  • With lossless/wave files, it tends to be that playback jumps to mono for a bit and then re-adjusts itself after a few seconds, but prolonged spells and/or quick flutters are also possible. With mp3 playback in foobar, if a file ends up in mono, it'll stick there until you reload/restart playing it.
The only possible lead I have thought of but not investigated is that it is a RAM-based problem. I know a link to a monitoring utility was posted the other day, so I'll look into that when I get chance, but as I say, I've been thinking about typing this for ages and I finally got bored enough of academia. If there's any other info I've missed I'll add it into the mix when I remember it.

Thanks in advance for any hints!
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