Last night I mixed the orchestra for a concert with Sara Evans, number 1 country artist. When you mix an orchestra of classical musicians together with a modern pop band, there are going to be some growing pains. This event was no different. Fortunately Sara’s band was all on IEMs so that was a good start. Guitar amps and Leslie cabinet were placed offstage and baffled. The drum kit was mostly surrounded by plexiglass. That’s a pretty good start but what ended up being the real issue was the house volume and the sub woofers that sit on the stage. My conversation with Doug Kirk (house audio engineer) was about cardioid subs.
Since a typical sub configuration is omni directional, when you put musicians behind the subs, it’s like being in front of the subs.
What are the benefits of using a cardioid sub configuration?
Improved low-frequency gain before feedback
Prodigious output to cover even the largest venues
Cardioid pattern control minimizes reverberation
Here are some Youtube videos with Dave Rat of Rat Sound explaining the difference between various sub woofer arrays. Part 3 is specifically related to cardioid subs arrays:
Here are some other Youtube videos related to cardioid subs:
There are a few common methods for achieving a cardioid sub array.
One involves placing the subs one in front of the other. I have seen this configuration with only (2) subs per side. Between the physical displacement and by delaying one of the cabinets properly, you create the desired cardioid pattern.
Here are some articles about cardioid subs: