16-bit PCM encoded at 8000Hz recordings (any other options)

16-bit PCM encoded at 8000Hz recordings!
We are uploading some custome IVR recordings from a text to speech application recording them as 16-bit PCM encoded at 8000Hz. All of these IVR’s sound like she has a lisp. Is there any other option besides 16-bit PCM encoded at 8000Hz? Can MP3 be used for system recordings?

Many Thanks.

mp3 can be used if you play it back momentarilly as a music on hold (interesting hack) but once again, it will need to be at a sample rate asterisk supports (I had an awful experience where my weather announcement sounded like satan after it attempted playback at 44100…too slow!)

check these guys out for TTS. its not GPL, but it works in some of my pinches. if anything less, it might give you some inspiration
research.att.com/~ttsweb/tts/demo.php

i believe if you install the asterisk-extras package asterisk can natively play .mp3 files…