Ah … time for another round of “three cents”.
1st. let’s make the distinction between EQ-ing a room (static EQ) and EQ-ing for mix purposes (dynamic EQ).
2nd. for static (room) EQ. Deathy is right, subtractive is preferable to additive. D-Jam is right too, it can sometimes pay to EQ the room.
Having said that, the EQ on your controller is totally unsuitable for room EQ-ing. I would suggest to NEVER use controller EQ to change the sound in the room. Controller EQ is there for a) mixing purposes and b) to change the EQ on a particularly high or low pitched track. So you should always use an EQ that sits in the chain between your controller master output and the speakers.
This could be on a DJ mixer that your controller plugs in to. That EQ has the same characteristics as the one on your controller and while available for room EQ, it is very NOT suitable for that purpose. Or it could be a PA mixer and while that EQ COULD be slightly more elaborate than on a DJ mixer, it’s still not ment to do room EQ with.
Essentially the best tool to fix room EQ is a (preferably 31-band) graphic equalizer. IF a venue has one in their sound chain, there is a fair chance someone more knowledgeable than you has set it for permanent use. This person and/or the house tech will, most assuredly, NOT be very amused if a DJ comes in and messes with their settings. More often than not they will actually keep that gear behind lock and key to prevent just such behavior.
Final note on this topic: Room EQ-ing is an art form and should really be avoided without proper knowledge, experience, skill and gear.
3rd. For dynamic (mixing) EQ-ing, you don’t have to worry about doing subtractive or additive. Just do what you feel you need to do to get the transition right.
Three point times three cents = 9 cents. Anybody got change for a dime?
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