Audio - so frustrating

Hi - I have the Cox Standard Package in the past - and it was OK - I have just expanded my package to the Expanded Plus some other stations - and now have an HD box.  Since I have had this I have had nothing but trouble with my TV's Audio.  The level of sound during commercials is terrible - on some channels i can have the level of the volume turned up almost as high as it will go - and it is still not great - (then watch out when a commercial comes on - just about blows the speakers).  Then - the most frustrating - when i go to change a channel - the audio is stuttering - and then the audio will shut down.  I usually need to reboot the HD box to get the sound back.  What is going on?????  I have already had your techs do a remote re-boot and it is still happening every time I turn on my TV.  Perhaps I should be looking for a new vendor?