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

[Stephen Bosch]

Kevin P. Fleming wrote:
> Stephen Bosch wrote:
> 
>> 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.
> 
> You are referring to the prompts distributed with Asterisk? Those sound
> perfectly clear to me, and to everyone else I know who has heard them.
> They were professionally recorded in a studio and then converted to GSM
> format, which does not introduce noise.

Recording them professionally in a studio is the right way to do it, of
course -- but that's probably not where the problem lies.

They sound noisy to me. First, the amplitude is low. When I increase the
gain in my sound card mixer, there is definitely audible noise (it's a
subtle static). I've sent the files to others to play back on different
equipment, and they tell me they hear the noise too. I don't think I'm
hearing things.

Right now, in our business, we've got voice mail provided by our telco
(Telus). The Telus prompts come in much clearer than the Asterisk
prompts. We've asked a couple of independent third parties to evaluate
Asterisk and the Telus prompts in comparison, and so far every person
has noted the noise on the Asterisk prompts.

If we want to sell systems running Asterisk, that's going to be a tough
one to get past, especially in these parts.

Perhaps it's the way the files are compressed?

-Stephen-