Asterisk is configured on the server with TDM410p card with two fxo and 2 fxs. The sound quality is fine when talking on the phone but the recording voicemail has poor quality. Also if greeting is recorded via ComedianMail, it also has poor quality.
Do you know what format you’re recording into? Check that.
in voicemail.conf the format is define as
format=wav49|gsm|wav
Try dropping the wav49 and the gsm from that format list.
I removed all the format except for wav but the result was same. I should add it here that when I record my personal greeting via comedian mail, the quality of the greeting is also poor. Also even though I see my personal greeting file in /var/spool/asterisk/voicemail/mailbox, it does not play when the caller get to my voicemail.
If that’s a Digium card, you’re welcome to take it up with Digium’s Support department.