Related to this, and hopefully part of what you either already know or what you might discover with the above experiment, is that we do not hear all frequencies equally.
Fletcher and Munson at Bell Labs were able to determine a set of ‘equal loudness curves’ pointing to the fact that we hear midrange frequencies (3 – 5 kHz) the most easily, and our response drops off from there.
As such, very high frequencies and very low frequencies are more difficult to hear. Thus, for distortion or other audio problems, this set of response curves is very important. If there is distortion in the midrange, then we will be more likely to hear it than if it is in the bass or the high treble.
For this reason, loudspeaker manufacturers (in particular) spend an enormous amount of effort to reduce distortion in this region.
This range of frequencies also happens to be an important component of vocal sounds, primarily to distinguish between consonants…
Ever wonder why it’s so hard to tell the difference between B, T, D and E over the telephone?
Several years ago I heard a demonstration by ServoDrive, a subwoofer company with a product that used servo motors instead of voice coils to drive the cones.
One point made has stuck with me: For a mix to sound solid, the midrange doesn’t need to be loud, only the bass.
The company proceeded to show this by playing a mix that was very heavy on the bottom, but light in the mids. Those of us attending the demo could talk to each other, yet the system seemed to be putting out a HUGE sound. I was impressed!
Since then I’ve always wondered why many mixers seem to push the mids into distortion…
In The Driver’s Seat
Another thing that affects system headroom, and thus distortion, is signals in the mix that don’t need to be there.
This is one reason why a lot of “old school” mixers know to use the EQ to cut only, never boost. I was taught that the first thing to do when considering how to start EQ’ing a mix is to begin cutting the low mids.
First, boost the EQ enough so that you can hear the effect, and then sweep the filter to find the most obnoxious frequency. Then cut that frequency 3 dB or so. By doing this on the majority of channels, I’m always surprised how much better the mix sounds.
On vocals, anything below 80 Hz isn’t needed (unless you’re mixing Barry White, and maybe not even then). Same for acoustic guitar. The only instruments that really need much below 100 Hz are kick drum, bass, maybe floor tom, keyboards, and perhaps electric guitar.
Not only is it important to keep most of the instruments out of the subwoofers, but it’s important to try and keep lots of low frequencies out of your mains. Tom Young did a great job here of describing how to incorporate subs via an aux channel. I used to do this when I was touring: Put the upright bass and kick drum mic into the subs, but nothing else. And it worked. Really well.
Wrapping It Up
My main point of all this is that we don’t have to make loud, bad sound, so please don’t. There are creative, clever ways to use almost any equipment better than we’re using it now. And there are better tools available for much lower prices than there used to be.
So then, making good sound or not becomes a choice. Learn more about the equipment you have, how to use it, and what new gear might solve some of the problems.
Get your ears tuned up by listening to acoustic music, quality recordings and quality show mixes. Do some ear training to learn to identify different frequencies, different kinds of distortion and other aspects.
It’s easier than ever now to make sound and to keep making sound. Now it’s time to make good sound!