Working for Texas Ballet Theater on “Peter and the Wolf – the children’s ballet”, I spent the last two days at the Mansfield ISD PAC. Huge place that barely gets used. The PA is made up of a stereo L/R JBL Vertec rig with subs at the top of the arrays. The balcony has it’s own (3) shorter JBL Vertec columns but that part of the venue wasn’t being used so that part of the PA was off. The venue also has curtains that block the balcony when not used so that helps the sound on the main floor. All in all, a fairly nice rig considering the venue gets used mainly for high school graduations. This gig was another reminder that being able to measure a PA is vital in this day & age. I could of EQed the PA based on listening to music & my own voice but measuring is simply a superior way of doing the work.

This capture shows that the house PA has excessive low / low mid content. Not a good thing. Especially when dealing with narration. Excessive low / low mid content for human voice makes it hard to understand the words.

If you set up your rig correctly, you can compare the input signal going to the console, the output signal coming from the console & the room response at the reference mic. After selecting the “pair” of signals you want to compare in the right order, you can see how well the compensative eq follows the room response at the microphone.

This is a capture of the original trace, the corrective eq trace & a measurement I made of the audio I/O. I have included the audio i/o measurement (green) because it helps explain the frequency & phase response of the console output. The low & high end phase drift & roll offs are an artifact of the audio i/o. Not the EQ itself.

With the compensative eq in place via the FOH consoles parametric eq, the end result is this which worked much better.