Ringtones loaded onto Digium phones using DPMA or using XML provisioning should be 16-bit, 16kHz raw signed linear audio files. .wav files are not acceptable. If a .wav file is used, distortion may be heard in the audio as the phone plays back the ringtone. In order to generate a raw signed linear audio file from a .wav file, the sox utility, or any other audio manipulation utility that can handle .wav and raw signed linear files can be used.
To convert a .wav file into an appropriate signed linear file, using the sox utility, the following command-line example should be used: