do you usually want the Master Volume higher. or the regular volume? also on pedals do you want to lower the amp volume and make the pedal volume higher or what?
You want to find a balance that sounds good to you (and preferably to whoever is listening to you). Different amps respond in different ways and the only way to find out for sure is to play with it.
Check out the Ultimate Settings sticky on UG. Very helpful and detailed.
Cranking the master volume can add poweramp distortion, which is great for rock. However, if you play metal, poweramp distortion can loosen up your sound and make it sound worse.
ultimate settings wasnt really helpful to me uldhppi because all amps are different
On your AD30, there are no tubes in the power amp, so it doesn't really change the sound too much. It would probably actually sound best at a normal volume a little above speaking level.