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Joe,
here the sound comes in definitely with 16 bits,
and also the 16-bit wav files are at the right level. I was
actually speculating that there might be a high/low byte (little vs big
endian) issue when wsjtx reads its audio buffers. At least that would
explain 48 dB too much sensitivity...
I've tried different audio levels by taking the
mixer slider from "normal" which has the green bar mostly topped up at 60 dB,
down to one tick producing under 30 dB. But this didn't sem to make much of a
difference regarding decoding success. Looks like it's more a matter of
"too-high SNR" than absolute audio levels?
BTW all the wav files seem to have 8 bytes missing in
their header, which prevents them from being played eg by Windows sndrec32. In a
hex editor, the first line shows up as
00000000 5249 4646 0000 0000
4500 0000 666D 7420 RIFF....E...fmt
while some software expects file length info
and a "WAVE" tag, like
00000000
5249 4646 F08F 0600 5741 5645 666D 7420 RIFF....WAVEfmt
.
Of course this is not a problem for reading in
WSJT, and good old Spectrogram (the one by R. Horne) doesn't seem to mind
either.
Best 73,
Markus (DF6NM)
Sent: Thursday, November 01, 2012 4:48 PM
Subject: LF: Soundcard issues
...
Could it be that
those who report having to move audio level sliders far
downward are using
24-bit soundcards, and their drivers are sending the
low 16 bits (via
portaudio) to WSJT-X? I do not presently have another
explanation. I do not find any level discrepancies here.
Obviously, I
cannot test hardware I do not have access to.
...
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