One of the questions that I get asked all the time is how I know what knobs to turn on the EQ section of the board.
I have found that if you can make it into a numbers game, turning the right knob becomes second nature.
When I teach sound, one of the things that I spend a lot of time on is frequency response.
That’s because for me, when frequency response was explained the light bulb came on.
All of a sudden things made sense and I could quantify what I was hearing.
Listen and Think Numbers
Once I explain frequency (you know the drill, hearing is 20Hz to 20KHz or 20,000Hz, low to high) I continue on in the training by giving anchor points. I start by drawing a horizontal line, putting 20Hz on the left side and 20KHz on the right side of the line.
Then I began talking about a kick drum normally being tuned in the 80Hz to 100Hz range and draw a vertical line just to the right of the 20Hz mark. This is anchor point one.
I then ask what a piano is tuned to, and every time someone in the audience will throw out A440. Bingo, 440Hz. If a piano is available I then hit the A440 key (the A above middle C) on the piano, or if a piano is not available I use a pitch pipe.
I then draw a vertical line to the right of 80HZ that is approximately 1/3 the way up the horizontal line Anchor point two.
Unfortunately, the next illustration is becoming less and less applicable as it is no longer used very often. If you are over 30 you will probably remember the emergency broadcast tone. For those too young to have heard or remember, the emergency broadcast tone was a 1,000Hz (or 1KHz) tone that played after the announcer would say “this is a test of the emergency broadcast system, this is only a test…”
I then do my best to replicate the 1000Hz tone vocally by saying DOOOOOOOOOOOOOOOO and trying to hold the pitch on or at 1KHz. Those who have been in one of my training session know that this is the weak point of the session.
As they say on American Idol, I am a little “pitchy” when I try to replicate the emergency broadcast tone. I then draw a vertical line to the right of 440HZ that is approximately 1/2 the way up the horizontal line. Anchor point three.
I then will selectively put the sound system that I am using into feedback by boosting frequencies on open mic channel. When the feedback starts I ask it that above or below 80Hz? Above, okay is it above or below 440Hz.
Above, okay is it above or below 1KHz? Below, okay our feedback issue is between 440Hz and 1KHz. Closer to 440Hz or 1Khz? You get the point. Now I know where to adjust the EQ knobs on my mixing board.
I can move the frequency knob somewhere between 440Hz and 1Khz and then use the level knob to cut the level at and around the frequency the sweep knob is on. I can then also move the sweep knob up and down until I hit the frequency that best solves my feedback problem.
For the younger crowd, and to the delight of those who may someday be in one of my training classes, I downloaded a frequency generator app to my phone. While my phone speaker won’t reproduce much below 150HZ. I am able to clearly play A440 and the emergency broadcast tone.
If you have a smart phone, download a frequency generator and play and memorize what different frequencies sound like.
When I was in college, whenever I was in the car and the emergency broadcast tone would come on, I would (to the chagrin of any passengers) turn the radio up and fixate on the tone, thus implanting the 1KHz frequency sound in my brain.
Once you can make equalization a numbers game and do it effectively, not only will you be able to control feedback better. You will also be able to better EQ instruments as when you go to adjust on the EQ section the memorized frequencies in your brain automatically turn into numbers that your hands can now masterfully set the EQ.
What is your technique for EQing? I would love to hear it. Post it in the comment section below.
Gary Zandstra is a professional AV systems integrator with Parkway Electric and has been involved with sound at his church for more than 25 years.