MikroTik

Hi,
Any ideas on how to ensure voice clarity using mikrotk as a server.In my queue tree I dedicated bandwidth of 64kbps/64kbps to voice with priority of 1,seperate interface and a public address but my calls still dont have good voice clarity any suggestions pls.

1. you can change tos value when mangling
2. try another codec

Tried all the options but still the problem persist. Anymore options.