[alsa-devel] C-Media CMI8738-LX noise in recording from line in

[Lars Schotte]

yes, I will post it, like I said, I am not on that computer now.

I dont have any windows now, so maybe I ll get some copy from
bittorrent or whatever, I didnt use windows for a long time.

I dont know if it has a passthrough. its only I cant otherwise explain,
why the sound card is working good on playback and the recroding is
such bad quality.

On Thu, 1 Apr 2010 13:14:04 +0200
Daniel Mack <daniel at caiaq.de> wrote:

> (please don't top-post)
> 
> On Thu, Apr 01, 2010 at 01:00:55PM +0200, Lars Schotte wrote:
> > OK. but the question is, does it put noise in recording in windows
> > as well?
> 
> Does it? Given that nobody else here happens to have the same audio
> card, I believe you're on your own to find out whether this is a
> hardware or driver issue.
> 
> > I maybe solved it w/ activating the old hd audio integraded snd
> > card, whichs broken, but line-in works and i tried it recording w/
> > it and that works perfectly. you say, that the cards never going to
> > have a good sound quality. I am sure it doesnt, but what I am
> > getting isnt even good enough. there is written on the box that I
> > can record with it in 44khz and so on, cd quality and whatever, so
> > is it a lie?
> 
> "44khz and so on" just tells you how the ADC/DAC works, it says
> nothing about the analog audio performance. So, vendors can screw the
> entire analog path and still claim they operating on CD quality
> digitally, yes. Welcome to the real world.
> 
> > i tried out manipulating w/ the mixer, believe me, however, i ll
> > post some output later, but the settings can not be set better,
> > because the only relevant setting here is the line-in and that is
> > already on maximum. the second thing that i dont understand about
> > this card is, that when I play sth at line-in, the sound is
> > perfect, but the recording is crappy. so does it have a line-in to
> > line-out passthrough?
> 
> Is there any software active to enable that pass-thru? Or is that a
> hardare feature?
> 
> > but then hows that possible that I can regulate it on my mixer and
> > even mute line-in completely?
> 
> Maybe you should provide the output you have been asked for, namely
> your mixer settings and the output of the alsa-info.sh script.
> 
> And the information about how the same hardware performs under Windows
> would also help you and other understand where the problem might be.
> 
> HTH,
> Daniel
> 
> 
> > On Thu, 01 Apr 2010 11:52:38 +0200
> > Clemens Ladisch <clemens at ladisch.de> wrote:
> > 
> > > Lars Schotte wrote:
> > > > The soundcard has following chipset - C-Media CMI8738-LX.
> > > 
> > > This chip was designed before on-board sound devices were common,
> > > and manages to have worse analog sound quality than many of those,
> > > especially on its inputs.
> > > 
> > > > So I try to record from the line in input, ...
> > > > its too silent and there is a lot of noise in it.
> > > 
> > > Even if your current mixer settings are suboptimal and can be
> > > improved (please show the output of "amixer contents" or the
> > > alsa-info output), be aware that this card never will have good
> > > quality.
> > > 
> > > 
> > > Regards,
> > > Clemens
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-- 
-------------------
Lars Schotte @ romy