I'm running sound for a Rock N' Roll summer camp in a roughly 300 cap audiotorium. Backline is set up on a stage about 50 feet wide.
Ampeg has graciously donated a nice svt-7 pro head and two 4-10 cabs for the bass rig. Aside from the one-trick-pony qualities of ampeg rigs, it's great. Problem is, it tends to create stage rumble, I think 100-125 hz, and it's been an issue both when the kids use it and the instructors, even when nothing is running in the PA. Since a bass head doesn't have a lot of equalization control, it's hard to isolate this.
I find that I have to crank the bass (taken direct, pre-eq from the head) in the PA to overcome the rumble and get any definition out in the auditorium (where it sounds fine eventually). What basic strategies might I employ, either in making adjustments on the amplifier or at the board, for controlling the stage rumble? Also, my PA is not delayed to the backline, could this be a contributing factor?
Thanks.
If I have an agreeable bass player who's willing to work with me, I have them turn down and give them the guidance to use it as their own personal monitor, not what has to drive the bass in the whole house. I've also had decent luck explaining that a good PA sub will have much better LF extension than the bass rig and they're best off not fighting me for reinforcement if they really want to sound good.
If they won't cooperate, and they're giving me all the volume and/or more than I need in the house, I cut the bottom off and only add clarity and definition through the mains. Delaying to the backline can help some, but otherwise it just becomes mush between the bass rig and the PA in smaller rooms like that.
