[SoX-users] Low quality mobile phone calls

[Pedro Henrique Morsch Mazzoni]

Hi everyone,

I am having problems with low quality mobile phone calls when submitting a
audio file through it.
I am sending the calls with a VoiceXML compatible provider (Nexmo) and it
seems that the mobile compression is messing up with my audio.
I have tried many file formats, rates, codecs, filters and effects. Still
no good result.
IMHO, the audio seems muffled, or something like that. It's happening only
with male voices.
I don't know if it is a mobile codec or transport(compression) issue
(europe to americas call).
Any ideas?

Thanks in advance,
Pedro Mazzoni

[Mike Morris WA6ILQ]

I need some help from a sox guru.

I have one directory with 260 sound files encoded as
Mono 44100 16 bit PCM wav files and a second
directory with 400+ wav files that are a mix of Mono
and stereo.

I need to batch convert them to mono 8000 u-law files.

I've spent several evenings experimenting with sox with zero luck.

I can play a file I've converted to mono 8k ulaw (with
audacity) with this command...

sox --no-clobber -D -G -S -c 1 -r 8k -t ul (filepath\filename) -d

The working environment is 32 bit Win7 ...

Thanks in advance...

Mike