Poor sound quality of files played by Asterisk via sound car

Hi,

Please open the following wav file and tell me what’s wrong with sound quality of files played by Asterisk + Celliax audio channel
to a sound card.

I am trying to discover what kind of distortion is generated and if there any chance to remove this distortion
by applying a filter.

Please let me know what is a correct format, bitrate, frequency , mono or stereo format of files recorded to be played
as MusicOnHold
and what application can be used for recording and what format should be set.

I have tried a number of wav formats and failed to get Asterisk to play these wav files as MusicOnHold.

Asterisk Celliax audio recorded by Audiocity in .wav file format

sendspace.com/file/nk6tb6