[asterisk-users] Audio Gain Settings

[Eric "ManxPower" Wieling]

Bob Smither wrote:
> On Fri, 2007-04-06 at 21:42 -0700, Yuan LIU wrote:
> 
> <snip>
> 
>> You are right.  zapata.conf is not used in IAX connections.  My reading has 
>> led me to believe that manipulating gain on an IP PBX is neither necessary 
>> nor practical in VoIP channels, so Asterisk does not devise such settings.
> 
> Thanks Yuan.  I beg to differ with the developers if there really is no
> amplitude control on IP channels.  I have an application where I am
> studying the spectrum of recorded voice.  When I call into my Asterisk
> box I have to hold the phone away and speak softly to avoid clipping the
> recorded waveform - clipped waveforms play havoc with the spectrum.
> 
> I guess it is time to study the source code (ugh!).

The device doing the IP/TDM conversion should be the device that sets 
the gains correctly.  The same applies to echo canceling.