Sound Card volume control question

Archived from groups: rec.audio.pro (More info?)

On 18 Jun 2005 10:13:16 -0700, "Fran Guidry" <fran.guidry@gmail.com>
wrote:

>Somehow I've gotten the idea that the software volume control in the
>Windows Mixer or other PC mixer software is post A/D conversion, and
>therefore useless. Is this 1. always true? 2. Usually true? 3. Not
>usually true? 4. Never true?
>
>Thanks for your input,
>Fran

Depends on the sound card. If the sound card has it's own utility
instead of using Windows' it's a good sign it is being done right. Of
the sound cards I am most familiar with, LynxOne and MIA MIDI have
digital volume controls and their own interface. Sound Blaster Live!
is adjusted in the analog domain whether or not you are recording
digitally.

Julian

Archived from groups: rec.audio.pro (More info?)

> Are you talking about recording (input) or playback (output)? I am
> also under the impression that level changes made with the Windows
> Mixer take place in the digital realm rather than controlling anything
> analog on the sound card, but I could be mistaken. I recently had an
> experience on a PC with a Sound Blaster card where the audio was
> clipping the Sound Blaster during playback. Reducing the master output
> and wave output levels in the Windows Mixer fixed the clipping. (Lest
> the obvious conclusion occur to anyone else, I made sure that the
> clipping wasn't happening further down the monitoring chain) So it
> seems as if the output levels are set pre D/A conversion, at least on
> this particular system with this particular sound card...

Upon re-reading this post, I realized that I was possibly mistaken in
my assumption regarding the location of the clipping. It's also
perfectly logical that the audio enters the D/A conversion at some
preset volume, then is modified in the analog domain on the sound card.
In my situation, I could have been clipping somewhere in the middle of
the sound card signal chain, rather than simply at the first step in
the chain. I hereby retract any claims of knowing what I'm talking
about.

Travis Garrison

Archived from groups: rec.audio.pro (More info?)

Fran Guidry <fran.guidry@gmail.com> wrote:
>Somehow I've gotten the idea that the software volume control in the
>Windows Mixer or other PC mixer software is post A/D conversion, and
>therefore useless. Is this 1. always true? 2. Usually true? 3. Not
>usually true? 4. Never true?

It is always true, because it's in software. That doesn't make it _useless_
but it limits the utility a lot, yeah.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Archived from groups: rec.audio.pro (More info?)

Fran Guidry <fran.guidry@gmail.com> wrote:
>Sorry, I was speaking of recording (A/D conversion). I have seen people
>suggest that one should pull down the record level on the Windows mixer
>or soundcard utility in order to manage noise levels but I have thought
>that these controls operate in the digital domain, after A/D
>conversion, and were simply throwing away bits.

Throwing away bits that are noise sounds like a good idea to me. If you
put as hot a signal as possible into the soundcard and turn the level down
in software after the fact, you don't get the best possible resolution.
So what? You get less of a noise issue, and with cheap soundcards that is
apt to be a more serious problem.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote in message
news928vj$a1s$1@panix2.panix.com...
> Fran Guidry <fran.guidry@gmail.com> wrote:
>>Somehow I've gotten the idea that the software volume control in the
>>Windows Mixer or other PC mixer software is post A/D conversion, and
>>therefore useless. Is this 1. always true? 2. Usually true? 3. Not
>>usually true? 4. Never true?
>
> It is always true, because it's in software. That doesn't make it
> _useless_
> but it limits the utility a lot, yeah.

Sorry Scott, it's actually in hardware... controlled by the software.

Even a low-cost codec chip like the Crystal CS4202 has this section in it's
datasheet. (Loosely quoted

"The CS4202 volume registers control analog input levels to the input mixer
and analog output levels, including the master volume level. The analog
inputs have a mixing range of +12 dB to -34.5 dB signal attentuation in 1.5
dB steps."

... and this goes for the integrated SoundMax codec in my Dell PC as well...

Based on this I think the answer to the question is: 1. Always true. (maybe
with few exceptions)

/Preben Friis

Archived from groups: rec.audio.pro (More info?)

Fran Guidry wrote:
> Thanks to everyone who replied.
>
> I did a little more research (imagine, someone who asks
questions
> before doing his own research ...) and discovered that the
LynxTwo
> mixer doesn't provide an input attenuator (I've been
thinking about
> recording inputs all this time, although I failed to make
that clear
> in my original post). Their recommendation for use of the
output
> volume faders warns that "To insure the highest signal
quality it is
> highly recommended that the faders be left in their
maximum position
> during critical recording and playback."

Among other things, as long as there is no clipping this
maximizes dynamic range in the analog domain - the equipment
attached to the Lynx.