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

On 18 Jun 2005 10:13:16 -0700, "Fran Guidry"
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

Fran Guidry 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.

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...

Travis Garrison

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

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.

Thanks,
Fran

In article .com writes:

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?

How about, yes it's true and no, it's not useless if you use it
judiciously and understand what can happen if you don't.

You don't want to use it to increase a low level substantially because
you'll amplify noise. You don't want to use it to turn down too high a
level because the input is probably already clipping the analog stage
ahead of the A/D conversion, so you'll reduce the level so that the
meters read right, but you'll still be recording a clipped signal.

But for making adjustments of a couple of dB, it's convenient and it
isn't really harmful.


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

Fran Guidry 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."

Fran Guidry 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."

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."

Fran

"Scott Dorsey" wrote in message
...
Fran Guidry 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

Fran Guidry 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,

Not necessarily

and therefore useless.

Not necessarily

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.

Preben Friis wrote:
"Scott Dorsey" wrote in message
...
Fran Guidry 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.

Right its controlled by software, and its possible that the
actual volume control function is done in the analog domain.
Not likely these days, but often true in the past.

The windows mixer is just an interface to the driver for the
particular audio interface. The driver is the interface to
the hardware.

In the old days many audio interfaces actually had analog
gain controls, resistor ladders and stuff like that.

The reason for the demise of analog gain controls in sound
cards is that the dynamic range of computer-controlled
analog gain controls topped out around 90 dB (example CS
3310), and the better audio interfaces got to be better than
that, or at least good enough that the cost of a good
computer-controlled analog variable gain element stopped
being worth it.