[linux-audio-dev] ATI-IXP overdrives PCM

Gene Heskett gene.heskett at verizon.net
Sat May 20 17:55:09 EDT 2006

Lee Revell wrote:
> On Sat, 2006-05-20 at 17:07 +0000, c wrote:
>> On Sat May 20, 2006 at 09:27:56AM -0500, Gene Heskett wrote:
>>> often sounding as if the playback is of a file that over-drove the d/a in playback,  or the a/d in the recording, eg clipped.
>> ...
>>> the ATI-IXP audio stuffs loaded
>> the ATIIXP in my MSI exhibits this same issue. essentially, if the 'PCM' level is set to 100%, things are horribly overdriven. the solution is to set the Master to 100%, and adjust volume with PCM, instead of vice versa. i guess whether this is a hardware bug or a driver bug depends on if PCM is the last point of software contact with the stream and master trims the levels after that, or if PCM just does some multiplication on the bits before passing them to the Master..
> Distortion if all volumes are set to 100% is not necessarily a bug.
> It's just the way some hardware works.
> Lee
We understand that all too well, from doing that particular balanceing 
act with the older SBLive cards, which could be run plumb out of digital 
headroom without even trying.

Cheers, Gene

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