PCM in Audio

I notice that my past sound cards have had a control marked PCM. I have
just installed a Creative Audigy card with the CA0106 driver, which shows
no such control under Kmix or under Alsamixer. It works O.K., but ALSA
prints error messages in a Konsole, about being unable to find PCM.

Is this anything to worry about? From Googling, PCM is a protocol or
interface much used by programmers. Generally, I suspect that Windows
spits out just as many error messages, but they are never seen, because of
the GUI-style navigation. Similarly, when compiling a program from source,
there are all kinds of warnings that suggest that the programmer didn't
know what he was doing, but they are so common that they are plainly good
practice, and they have no consequences.

Doug.

Doug Laidlaw wrote:[color=blue]
> I notice that my past sound cards have had a control marked PCM. I have
> just installed a Creative Audigy card with the CA0106 driver, which shows
> no such control under Kmix or under Alsamixer. It works O.K., but ALSA
> prints error messages in a Konsole, about being unable to find PCM.
>
> Is this anything to worry about?[/color]

Not really.
[color=blue]
> From Googling, PCM is a protocol or interface much used by programmers.[/color]

PCM is short for "pulse coded modulation", which, in more modern terms,
is just "digital audio". IOW, as soon as a program generates sounds and
feeds them into the soundcard, the PCM volume control defines the volume
of this signal as it goes into the mixer. There, it is mixed with the
audio signal from other sources, namely the CD, line-In and AUX inputs
(if there are any), and then again, the volume is adjusted again with
the global volume control. Lack of the PCM mixer just states that you
cannot adjust the volume of digital sound relative to all other sound
sources, though you still have a volume adjustment that works globally
on all sources.

Greetings,
Thomas

Thomas Richter wrote:
[color=blue]
> Doug Laidlaw wrote:[color=green]
>> I notice that my past sound cards have had a control marked PCM. I have
>> just installed a Creative Audigy card with the CA0106 driver, which shows
>> no such control under Kmix or under Alsamixer. It works O.K., but ALSA
>> prints error messages in a Konsole, about being unable to find PCM.
>>
>> Is this anything to worry about?[/color]
>
> Not really.
>[color=green]
>> From Googling, PCM is a protocol or interface much used by programmers.[/color]
>
> PCM is short for "pulse coded modulation", which, in more modern terms,
> is just "digital audio". IOW, as soon as a program generates sounds and
> feeds them into the soundcard, the PCM volume control defines the volume
> of this signal as it goes into the mixer. There, it is mixed with the
> audio signal from other sources, namely the CD, line-In and AUX inputs
> (if there are any), and then again, the volume is adjusted again with
> the global volume control. Lack of the PCM mixer just states that you
> cannot adjust the volume of digital sound relative to all other sound
> sources, though you still have a volume adjustment that works globally
> on all sources.
>
> Greetings,
> Thomas
>[/color]
Thanks Thomas. I have a Ham license, so I understand what Pulse Coded
Modulation is.

Doug,
VK3KDI.