calibrating the 888/24

[kir2k2]

before i try this i wanted to get some opinions onhow i should go about doing this.

i have a ghost 32 and 2 888/24's and when recording vocals i dont get much of a level into pro tools. i have been told that i should calibrate the 888's.. if so what setting should i calibrate them to and where should i set the headroom level?

what is the best source to calibrate to? i was told i could use the vu meter on my avalon with all the settings off and just go through the line input on the 737. would that work or should i get a seperate vu just to calibrate to?

thanks...................