I'm converting VOX files (from a Dialogic telephony board), to WAV. I
use CoolEdit2K to 'view' the files.
'Capture' platform: P1-200MHz, Dialogic=D40A (firmware rev 56), MS-DOS 6.22, d40drv ver 4.21
File: 6kHz, 4-bit Dialogic ADPCM
When the VOX file is viewed in CE2K the waveform looks fine.
I then do:
sox -r 6000 -t vox RECORD.VOX -t wav RECORD.WAV
and the resultant wave file, when viewed in CE2K, has its 'centerline'
below the 0dB line in CE2K's waveform view.
I (visually) see an identical effect using 12.18.1 and 13.0.0, though
the two output files appear to be 'binaryily' different.
Using 12.18.1, if I adjust the command to include some DC-bias (.018 &
.0001 are some effective, 'magic numbers' I deduced):
sox -r 6000 -t vox RECORD.VOX -t wav RECORD.WAV dcshift .018 .0001
then the resultant WAV file doesn't exhibit much, if any, of this
offset/bias. I suppose the same 'fix' in 13.0.0 would work too.