[TriLUG] How to hear what you're digitizing???

[Steve Litt]

On Monday 03 May 2010 13:25:19 Steve Pinkham wrote:
> If you're just monitoring for those types of problems and not mixing
> audio, you can use alsamixer to select the input you would like to
> monitor and bypass the recording programs entirely.

I'm looking at alsamixer and I don't see how to do this. Which input would I 
select? Available inputs are:

PCM
Line
Mic
IEC958
IEC958 D

Available outputs are:

Master
PCM
Front
Front Mi
Front Mi
Surround
Center
LFE
Side

I need the phonograph as input in order to digitize the record. By the way, 
this doesn't work:

arecord | tee myrecord.wav | aplay

The preceding gives feedback -- apparently the output of aplay feeds back to 
the input of arecord.



> 
> Do you really have hardware that is capable of producing 32 bit output?

No way. I have a twenty dollar sound card, or maybe it's built into the mobo 
-- I don't remember.

>   32bit is useful as in intermediary format for editing, 

That's what I'm using it for. I want to record 24db (8 bits) low to avoid any 
clipping without user intervention, and still grab enough data that 
normalization simply lops off the top 24 db (8 bits), producing a high 
quality, minimally interpolated, 24 bit recording. Cool, huh?


>   but for input,
> 24bit far exceeds the capability of any input device I've seen.  If your
> input hardware puts out 16 bit or 24 bit information, storing in 32bit
> gives you no added benefit you can't get later in whatever program you
> use to do normalization.

Is what you're saying that my sound card's A/D converter yields only 24 bits 
to the CPU, so my 32 bit .wav is an interpolation of the hardware 24? If so, I 
see what you mean.

How can you tell the hardware bit depth of your sound card?

SteveT
 
Steve Litt
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