Re: Input gain on M-Audio Audiophile USB

[Pierre-Antoine Champin <alsa-050822@champin.net>]

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Richard Smith a écrit :
> Anybody have any idea how to change the line in input gain on the
> M-Audio Audiophile USB?  The way its currently set renders it useless.
>  It's just too hot.   If you connect any normal line level source up
> to it it just bangs the input rails.
> 
> Alsamixer tells me there is not a mixer.
> 
> I know its possible because if you try the same setup under win2k then it works.
> 
> I've tried 1.0.9 and 1.0.10rc3 and they have the same behavior.

I've not tried it recenrly, but the last time I did, I first thought I
had a gain problem, while this was actually a wrong byte order: it was
neither low-endian nor big-endian, but a strange mix, causing low-weight
values to be considered high-weight, hence the saturation impresson.

Filtering the input through a program which changes the order of the
bytes (a,b,c -> c,a,b) gives a good sound; but of course, it kills latency!

I attach the script I used to test that. I'm not sure this is the
problem you have, but it is worth a try.

  Pierre-Antoine



[-- Attachment #2: swap2.py --]
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#!/usr/bin/python
import sys

while True:
    try:
        a,b,c = sys.stdin.read (3)
        sys.stdout.write ("".join ((c,a,b)))
    except ValueError:
        break