[Gllug] Sound recording - distortion

[Phil Reynolds]

On Tue, Jun 14, 2005 at 09:11:51AM +0100, Ken Smith wrote:
> 
> 
> > > > Is distortion a common problem when recording sound using a VIA
> > > > 8237-based motherboard? I am finding it so but was wondering if there
> > > > was a known good way to fix it.
> > >
> > > Is the volume level going into the card too high? Is there another
> input -
> > > you might be using the Mic level one by mistake.
> >
> >
> > Well, I am definitely using the line-level input...
> >
> > The input is from a standard hi-fi amplifier (tape loop).
> >
> > I have tried reducing the level (snd kept sticking but audacity is OK)
> > but I still get noticeable "mush" and squeaking.
> 
> Earth disconnected, some feedback path somewhere leading to squeeking, Some
> strange setting leading to a feedback path in the sound sub-system - ALSA
> settings. I have an SBLive with that problem if I set ALSA mixer  wrongly.

Well, there's so many settings on the mixer, I can't tell which ones do
anything that readily - so maybe some help with that would be
appreciated... the squeaking does not seem to be feedback - more a
"squeakiness" on the high frequencies.

The mixer has this bewildering array of settings ((R) = recordable):

Master
Master Mono
PCM
Surround
Center
LFE
Line (R)
Line-In As Surround
CD (R)
Mic (R)
Mic As Center
Mic Boost (+20...
Mic Select
Video
Phone (R)
IEC958 (R)
IEC958 Output
IEC950 Playback AC97...
PC Speaker
Aux (R)
Mono Output Select
Capture
Mix
Mix Mono
Duplicate Front
External Amplifier
Input Source Select
Input Source Select 1
VIA DXS
VIA DXS 1
VIA DXS 2
VIA DXS 3

> Pickup from the inverter in the PSU. You could try putting the SB128 in
> there - somehow I doubt the MB sound input would be that awful (IE: 10-15 db
> S/N ratio) but its awful hard to get really good performance from an A/D
> that's inside a PC. Its better to digitise sound externally and bring it
> into a PC as digital S/PDIFF or AES/EBU.

However, that's the expensive way - yes, I know it is the best way but
not really an option for me.

-- 
Phil Reynolds
 o  ____ mail: phil at tinsleyviaduct.com
|L_ \  / Web: http://www.tinsleyviaduct.com/phil/
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