Re: [Alsa-user] Re: ALSA is dreamware on my system...

[Bill U. <un...@ph...>]

On Sat, 13 Mar 2004, Casey Heshler wrote:

> Considering that this has had no responses for more than a few days, I am 
> bringing it up for anyone new that has been added onto the list.

I would advise recording in different ways.

a) use arecord.
if the card is capable of 44100 use
arecord -f cd >/tmp/recording
and see if the noise is there in /tmp/recording.
b) Use the oss and some recording program like gnoise etc to record from
/dev/dsp.

c) Try different inputs. If there is a mic input ratehr than line in,
use it (unmute the mic input and mute the linein.)

d)Do it without monitoring the output-- ie switch off the output to se
fi that makes a difference. 

This kind of noise is not usual, which is probably why noone has
responded. Ie, no one has seen it befor and thus can offer no advice on
how to get rid of it. 

It is of course also possible that the card is defective, and a new
sound card would work better. While I have gotten the Maudio transit to
work and while it is a very nice usb based card and cheap, I would not
recommend it because of the current incompatibility with the Linux USB
software. (See www.theory.physics.ubc.ca/transit.html for the kludge
needed) but other soundcards also work well. 

The noise that I see on your recodings is very strange, and I am at a
loss as to how it could occur. One could suspect electrical noise except
one would expect more structure in the noise spikes if that were the
case. These are just delta function spikes with very little internal
structure (even though they extend over many samples). And they are not
consistant in height.


> 
> The noise issue has not been resolved, and continues to plague my 
> recordings...
> 
> System Specs:
> AMD 1.7GHz processor
> 512Meg RAM
> 500Meg Swap
> 41 Gig hard drive, with Knoppix v3.3 (2,4,22-xfs kernel) hard drive installed
> ALSA installed, and working...
> ALSA Information:
> Driver version 1.0.2c
> Sound Card: VIA686A - VIA 82C686A/B rev50
> 
> I wouldn't have brought this up a second time, if not for the fact that: One, 
> my business is at a stand-still until I can get a "clean" recording, and two, 
> this is still un-resolved.
> 
> Thank you for anyone who can get me, and my business, back into running 
> again...
> Casey
> 
> On Tuesday 09 March 2004 07:46, Casey Heshler wrote:
> > On Tuesday 09 March 2004 18:15, Bill Unruh wrote:
> > > On Tue, 9 Mar 2004, Casey Heshler wrote:
> > > > On Tuesday 09 March 2004 01:48, Bill Unruh wrote:
> > > > > On Mon, 8 Mar 2004, Casey Heshler wrote:
> > > > > > On Tuesday 09 March 2004 01:20, Bill Unruh wrote:
> > > > > > > On Mon, 8 Mar 2004, Casey Heshler wrote:
> > > > > > > > On Tuesday 09 March 2004 00:45, Bill Unruh wrote:
> > > > > > > > > On Mon, 8 Mar 2004, Casey Heshler wrote:
> > > > > > > > > > > But PLEASE - before finally removing ALSA, record the
> > > > > > > > > > > type of static/noise you get and place it somewhere for
> > > > > > > > > > > others to download/diagnose. Otherwise you would have
> > > > > > > > > > > filed irate complaint after irate complaint without
> > > > > > > > > > > anyone being able to diagnose the issue with some helpful
> > > > > > > > > > > data. ;-)
> > > > > > > > > >
> > > > > > > > > > I would love for "someone" to hear what I am hearing - I
> > > > > > > > > > can post a 10 second WAV file, but my concern is - how, and
> > > > > > > > > > where, do I do this? Can I place the file in a "common"
> > > > > > > > > > local location, and then post the target area???
> > > >
> > > > Bill, didn't have ncftp, but I was able to follow your directions on
> > > > the "ftp" - the file (wav) has been placed where you asked, and under
> > > > the name you requested. Hope this helps with a little diagnosis...
> > >
> > > The file is at
> > > ftp.theory.physics.ubc.ca/outgoing/heshler.wav
> > > and can be downloaded via anonymous ftp.
> > >
> > > And teh noise really looks like noise. It has different levels in the
> > > two channels, and is up to 40 bytes wide (10 samples) of consistant
> > > level-- ie the signal level does not change much in that 40 bytesi--
> > > however the signal level in the two channels differs. It occurs in quiet
> > > areas and in "full volume" areas. (The max amplitude of the signal is
> > > about 50% of the max possible, and the noise spikes go up to about 25%
> > > but with very varied heights.) It looks almost like some sort of
> > > electical noise.
> > >
> > > Remind us again how this was recorded?
> >
> > This sound clip was recorded with ReZound, but I get it with "any"
> > recorder; Audacity, Sound-Recorder, and even KRecord - The sound clip is
> > coming in from a cassette tape deck in through the "Line In" of the VIA
> > Sound Card - with "Capture" set on the "Line In".
> >
> > The sound clip was "monitored" - i.e. I listen to the "Line In" while I
> > record, and the noise is not in the sound at that time. I have the levels
> > set to about 65% - I view and change the levels through AlsaMixer,
> > AlsaMixerGUI, and - my preferance - KMix - This recording clip was done as
> > a last ditch effort to eliminate possible "feedback" from other channles -
> > I muted all channels except for IGain in KMix, or the "Capture" in the ALSA
> > mixers, and still the noise, as apparent, was still introduced.
> >
> > I playback through a combination of players, preferance being ReZound
> > because I think I need to change sample rates, from what I had problems
> > early on, my sample rate for my sound card appears to use 48KHz. But, I
> > also can use aplay, XMMS, ReZound, and Audacity for playback - most of the
> > time I need to use a player that has a "visual" editor, because this "sound
> > clip" is part of a 45 to 50 minute analog tape speach, that I one-pass to
> > digitize, then second pass, strip out each speach, final pass is to remove
> > pre and post silence and get the sound speach ready for cd audio burning.
> > Which is they business I provide for my customers.
> >
> > Thank you Bill, for proving I am not insane, and that the noise is "real".
> > Hopefully someone can resolve this - as I said before - this has "only"
> > shown up since I changed to ALSA - it was not in my previous sound with
> > Knoppix/Debian, and nothing has been changed in the sound system other than
> > that.
> >
> > Casey
> 

-- 
William G. Unruh   |  Canadian Institute for|     Tel: +1(604)822-3273
Physics&Astronomy  |     Advanced Research  |     Fax: +1(604)822-5324
UBC, Vancouver,BC  |   Program in Cosmology |     un...@ph...
Canada V6T 1Z1     |      and Gravity       |  www.theory.physics.ubc.ca/