[Asterisk-Users] Correction: Asterisk sound files, audio bandwidth, and sound quality

[Stephen Bosch]

Kevin P. Fleming wrote:
> Stephen Bosch wrote:
> 
>> 1. Can I *record* audio from a TDM-400 channel at a sample rate above
>> 8 kHz? Can I record at 16 bits? (This is most important.)
> 
> No TDM hardware supports sample rates above 8KHz, since that is what the
> PSTN is designed for. Zaptel hardware can possibly be convinced to
> supply 16-bit signed linear audio, but I don't know of anyone who has
> tried it. Normally the hardware provides the audio stream already
> compressed to 8-bit ulaw or alaw.

When I listen to the GSM compressed prompts, I can hear subtle noise
when the person is speaking -- this is irrespective of whether I listen
to the prompts through the TDM-400 on an analogue phone or whether I do
so directly on a workstation. It has to be possible to do better than that.

It doesn't have to be CD quality sound, but it should be clear. How can
the sound quality be improved within the limitations of an 8 kHz sample
rate?

-Stephen-