We get a professional company to record a message for MoH. The file we get is a wav 44,100Hz 16bit mono and sounds good when played through media player on a PC.
The resulting encoded files from our Cisco Unified CallManager 4.2 box sound Ok except for the pronunciation of 's' which sounds awfully crackly. This is for both the 711 ulaw and alaw files (our box uses the 711 ulaw).
Is this a common phenomena, or does anyone know of a way to fix the problem? The crackly 's' is so bad we are thinking of no longer using the MoH facility.
This is a fairly common problem, have a look at the excellent answers from Gonz @ Cisco Systems in this thread (especially this clip "The best recommended method is to record the audio with the parameters - 16-bit PCM sampled at 16 KHz");
Hope this helps!