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

[Stephen Bosch]

Hi, Steve:

Thanks for your comments!

steve at daviesfam.org wrote:
> The recorded prompts supplied with Asterisk are encoded with the .gsm 
> codec.  That makes them sound like audio sounds on your GSM cellphone.  
> Which is noticably worse than true PCM audio.
> 
> Now in the telephone world "best quality" still isn't very good - its ulaw 
> or alaw encoded 8kHz audio.  That's frequency response up to 3.5kHz and 
> about 12 or 13 bits of dynamic range.
> 
> But the fuzzyness you hear on the standard Asterisk prompts is due, I'm 
> sure, to the use of gsm compression.

<snip>

> Now Digium hasn't made the standard prompts available in a format other 
> than gsm.  I don't know why.
> 
> For us we recorded the prompts in South African voice and so we have 
> those.  You need to either extract the original non-compressed prompts 
> from Digium (if they have them), or take it as an opportunity and record 
> your own set in Canadian accent.

How ironic that Allison (the woman who did the Digium prompts) is
Canadian...

We are planning to do our own prompts anyway, so that's not a problem --
your input has been most helpful; at least now I have some idea what our
options are.

Thanks!

-Stephen-