How Do Techs Magically Pinpoint a Problem Frequency?
It takes a few attempts.
So there I was, hunkered down in the sound booth with the congregation rioting around me. Two instruments were vying for the same dominant frequencies and I could hear an elder yell, “MAKE THIS NIGHTMARE END!” Sweat was pouring down my face. “Think man, think,” I told myself. “You’ve trained for this very type of scenario.” My hand reached for the channel EQ. I moved the mid-range sweep knob to 1257 Hz. Suddenly, confident of my next move, I applied a 6 dB cut to that frequency…and the congregation went wild!
This story seems outrageous but in the mind of some audio techs, it reflects a question I occasionally get via email; “how do techs pinpoint a frequency so easily?”
There are four ways that techs learn to pinpoint frequencies…but “pinpoint” isn’t the best description. Let’s look at the four and you’ll see what I mean.
1. It’s what I do every day.
It takes 10,000 hours to master a skill. Working weekends and maybe a mid-week practice, it would take 24 years of working 8 hours on live mixing each weekend, every weekend. Professional audio engineers are putting in a lot of more time and thus they have trained their ears to identify frequency areas in relationship to vocals, guitars, drums, etc. Even with that type of near-every day experience, could they pinpoint a specific frequency? No. They would be able to be very very very close in finding the frequency area for their first modification.
2. I trained my ears.
It is possible to get a jump on mastering frequency area identification if you train your ears. When it comes to this, there have been a number of products which help with this training. Quiztones is a great one. Some people have golden ears and it’s easy for them to identify the frequency area they need to change, but for most people, it takes training your ears.
3. I learned the common frequency areas.
Each instrument and vocal has a set of audio frequencies that are known to affect the sound in a certain way. For example, here are two key vocal frequency ranges and their use:
100 Hz – 300 Hz : Clarity / Thin (Good for cutting)
400 Hz – 1,100 Hz : Honky / Nasal (Good for cutting)
Knowing these frequency ranges, you know the frequency area you should first investigate when you have a problem with your audio channel…or you don’t have a problem but you want to improve the sound, such as add presence to a vocal or an acoustic guitar. My guide, Audio Essentials for Church Sound, covers all of these frequency areas for the different instruments and vocals.
4. I learned to sweep.
Looking at the previous three points, you’ll notice I didn’t mention how one learns to “pinpoint” a frequency such as in the 1257 Hz in the above story. It’s because you can’t. The best you can do is come close on your first attempt and from there, “dial it in.” Let’s look at how you’d do this.
First of all, it doesn’t matter if you are on an analog or digital board as the concept is the same. Let’s go with an issue where your vocal is a bit on the nasally side (some vocalists are like that, you work with what you’ve got). Focus on the below rage:
400 Hz – 1,100 Hz : Honky / Nasal
Go to your mid-range sweep EQ knob and move it to 400 Hz. Next, set the mid-range cut/boost knob at +6 dB. You have now applied a 6 dB boost at 400 Hz. Using the mid-range sweep knob, slowly sweep your frequency center point up until the nasally characteristic jumps out in the mix. You might find it at 800 Hz or 1,011 Hz or 1, 100 Hz. Once you find the right point, cut the frequency area to the amount you need. +6 dB is used because it’s easier to listen for extremes and adjust once you’ve found the point.
The next time you’re mixing that vocalist and they sound nasally, you have a good idea of the frequency area you should give that initial cut before sweeping a bit to make sure you’ve dialed it in.
The Take Away
I encourage you to focus on the last three points. Start by learning the key frequency areas for instruments and vocals. Then check out Quiztones and train your ear to recognize those frequency areas. Finally, learn to sweep. Even if you don’t use Quiztones or regularly train your ear, if you know the ranges and learn to sweep to find the right spot, you’ll be doing great!
Article Originally posted in BehindTheMixer.com by Chris Huff, updated on OCTOBER 11, 2013