Blog Of Rick Pepper

In this installment I’m going to talk about house (main) EQ. That is, having (ideally) a 31 band EQ somewhere between your console and your power amps. For instance, my signal chain goes like this; Mackie SR32.4 console, right main out goes to a Rane 31 band EQ, then a Rane AC23 active crossover, then to a QSC MX2000A power amp. The subwoofer signal path is similar.

I think most will agree that the purpose of the EQ is to match, or optimize your speaker response for your room to some sort of standard that yields a consistent and predictable behavior as far as frequency to amplitude relationships. What that means is, every speaker has some “personality”, it has it’s own frequency response biases (which can be a selling point for integrated powered speaker systems such as those from Mackie.) Every room has it’s own resonances; peaks “nodes” and nulls – wavelengths that are canceled resulting in a dip in response. Add those together and you do not have a predictable, consistent response in your system. If you don’t have a main EQ in your system, ask yourself these questions: Do you make similar EQ adjustments using the channel EQ on several mics to make them sound “right”, do you find that voices are consistently very dull, or very bright, do you find that most acoustic guitars sound boomy, or thin, or bass guitars have no meat to them. These are all possible symptoms of an improperly tuned system. Enter pink noise (and/or a whole host of other optimization tools/techniques) and the graphic EQ. Pink noise offers a consistent noise source that can be monitored mathematically by a calibrated mic (not just any mic will work – I’ve heard of people using SM-57’s for this!) and an analyzer. These tools help you hone in on problem frequencies – whether as peaks or dips. Another important factor I want to bring to the attention of those also trying to record their sermons with a simple workflow (not unlike mine which I’ve discussed here before), and that is that you will find you get a much more natural and balanced sound when you have your system optimized for your room because the adjustments you now find yourself making on a channel strip are those unique to the individual sources, not to compensate for (global) poor system/room tuning. This should translate into better performance on most other playback systems. Conversely, if you take a recording done on a system that is not optimized, and play it back on one that is, what you’ll hear is the correction you’re adding with your channel EQ settings to compensate for your system’s lack of optimization. Another option is to put a graphic EQ inline with your recording device specifically to compensate for this, but at that point you have to ask yourself why you don’t just put that money into a main EQ which will improve the performance of your entire system, not just the recording bus.