I agree, but subjectively speaking, 3dB is the breaking (or break OUT) point in loudness.I think even 3db is too much personally...
The difference between a Greenback (97db) and a G12H30 (100db) is a HUGE difference...
Make sure each type of speaker's sensitivity is not more than 3dB off from each other, or one pair will be noticeably louder.
Are your Scumback H75s in the 2x12 the 65 watt versions?
The V30 H30 X pattern is an awesome combo for metal (or any style really). The speakers complement each other perfectly filling in the sonic gaps the other one misses. V30s have a big mid push and H30s are a bit scooped with a bigger bottom and brighter top so when you mix them you cover all bases.
Are your Scumback H75s in the 2x12 the 65 watt versions?
what are H30s?
Who makes scumbacks??