Customizing System Prompts
In keeping with the seemingly limitless flexibility of Asterisk, you can also modify the system prompts. This is very simple to explain, but generally difficult to do well.
With over three hundred system prompts in the main distribution, and over six hundred more in the asterisk-sounds add on, if you’re contemplating customizing all of them you’d better have either a lot of money or a lot of time on your hands.
An audio engineer is also recommended, to ensure that the recordings are normalized to -3 dB and that all prompts start and end at a zero-crossing point (with just the right amount of silence prepended and appended).
Once you have the recordings, the actual implementation is easy—simply replace the files in /var/lib/asterisk/sounds/ with the ones you have created.
Alternatively, you can opt to record your own prompts and place
them in a folder of your choosing. When you refer to sound files with
the Playback() or Background() applications, you can refer to
the full pathname of the sound file, or to any subdirectory of
/var/lib/asterisk/sounds/.
A useful way to convert your WAV files to ...