Most people reading this article have, at one point or another, heard a bad sounding show with some annoying frequencies, or with an unbelievable amount of feedback. The question is, why? More often than not, this can be avoided by properly recognizing problem frequencies and giving them some needed attention.
Many of the acts that come through Vegas carry their own engineers. At that point, I become a system tech more than anything else. Being in that position allows me to see the techniques and skills of guest engineers on a daily basis. Some are better than others (yes, I know, this is subject to personal opinion), but it's interesting to see how they all try to achieve a common goal: to make everyone happy and everything sound "good."
A few tools that are often seen on the show site to tune a rig include an RTA (Real Time Analyzer) and an analyzer with a trace function. While these tools are extremely powerful and useful, it is often argued that, "it doesn't just come down to what's on a computer screen." This is absolutely the truth, and nothing can ever replace having a trained ear to help tune a system.
Students in college who are studying music go to an actual class called "ear training." This class usually helps musicians recognize chords and notes just by hearing them. While recognizing chords isn't necessarily as important to an audio engineer as a musician, recognizing frequencies by ear is a very important part of engineering. The good news about all of this is that there are some ways to easily train your ear. The hardest part about training your ear is actually sitting down and doing it.
Musical Notes and Frequencies
{mosimage}Specific musical notes relate to specific frequencies. In fact, a big part of what makes instruments sound different from one another are the combination of frequencies within one musical note on any given instrument or voice. This usually includes a primary frequency with multiple harmonic frequencies of that primary frequency. To show the relation between frequencies and musical notes take a look at Fig. 1. You can see that each note on a piano has a different frequency associated with it (the frequencies listed are primary). This is an important concept to have an understanding of. Just as an example, if a certain note is starting to feed back, and an artist says "it only does that when I hit a C," you will have an even better idea of what frequencies to start adjusting.
Easy Ways to Train Your Ear
Whether you are new to the industry or are just looking to sharpen your frequency recognition a little bit, getting started with training your ear is easy. Over the years I've seen and thought up a couple of ways to get more familiar with frequency recognition. The good news is that it doesn't require anything super-expensive, and it's easy to set up.
The first way is to simply take a microphone, plug it into a mixer with a third octave graphic equalizer and into an amplified speaker. Then turn the microphone up to a comfortable listening level and start boosting and cutting different frequencies to get familiar with what each one sounds like.
Once you get more familiar with the sounds of different frequencies, close your eyes, grab a random frequency, boost it and/or cut it, and then try and guess which frequency that you are affecting. The more you do it, the closer your guesses will get. Eventually (hopefully) you'll be dead on.
Another way to work on training your ear is to use a sine wave generator. Some acoustical analysis software and mixing consoles have these built in. But if you don't own either of these, they are easy to find online. Once you have an operational sine wave generator, turn the volume up in a pair of headphones or a speaker to a comfortable listening level. Then, just as with a graphic equalizer, grab the frequency knob/slider and randomly listen to different frequencies. Close your eyes and start trying to guess what frequency it is. Over time you will be able to recognize frequencies faster and more accurately. Those of you in the iPhone tribe can download the app, Dog Whistler, which creates tones at specific frequencies.
Listening Tests
I know of a few companies that used to have periodic "listening tests," where engineers at the sound companies would get to see how accurately they could call out frequencies. The boss would play random frequencies, and the engineers would guess. Their scores would depend on how close their guesses were to the actual frequencies being generated. I haven't seen this in a long time, but I'm sure sound companies could benefit from a whole crew that has accurate ears.
Having a "good ear" doesn't come overnight for most people. It takes a lot of listening and experience, just like anything else in this business. While training in the shop or at home is a good idea, nothing can replace being on a show site, "under the gun," and having the confidence that you can accurately pinpoint what you're hearing.
