Mind-Blowing Midrange: A look at the frequencies that make the cut
By Daniel Brooks
It is a common experience for budding guitarists. You hear a song with a guitar part that just blows you away, and you realize that, more than anything, what you really want to do is make music. You get some gear. You practice . . . a lot, maybe even a bit obsessively. You experiment until you find that epic sound, the one with the scooped mids that embodies the awesome power of the guitar even when it is played just by itself. You master a small but ever-growing corner of the music universe. Then you find some guys, or girls, who want to play in a band with you. You set up your gear, count to four, and wonder what happened to all of your awesome sound.
It’s probably not a matter of volume. Any reasonably loud amp with at least 20 or 30 watts of power should make enough sound to be heard amidst the basic configuration of drums, bass and voice in a rock and roll band. Your amp is probably loud enough. The problem is simply that you are playing with other instruments, each of which has its own place on the broader spectrum of audible frequencies a whole band produces. That massive low end that adds seismic significance to your sound when you are practicing alone is lost when you play with a bassist. That sizzling high end you thought would cut through anything doesn’t have enough behind it to push past the drums and cymbals. Your awesome sound is lost because the guitar’s voice lives in that midrange you’ve “scooped” to get that badass solo sound.
Those midrange tones are vital. They form, and define, the essential part of any musical sound. Most instruments are rooted in the bass to lower mid range of frequencies, which corresponds roughly from 100 to 140Hz to around 2,500 Hz. Rarely does the fundamental frequency of any note on any instrument go higher than 3,000Hz. The range of notes for a 22 fret guitar in standard tuning, for example, is 82.407Hz (E2) to 1174.7 Hz (D6).
Of course, we can and do hear higher frequencies than these. Each vibrating musical instrument creates harmonics, vibrations that resonate at some multiple of the fundamental frequency. Harmonics can occur at any multiple of the fundamental frequency and can, in turn, interfere with one another or reinforce one another, depending on their frequency, phase, relative strength and natural resonance of the instrument. Every musical instrument, everything that vibrates, for that matter, creates its own signature pattern of harmonics that defines its sound. The pattern defines the timbre or the “voice” of the sound and tells you that the note you hear is being made by a guitar or a bass or a human voice, or the specific human voice of someone you know.
Our ears are especially tuned to the sounds of a human voice. We are social creatures whose environment is largely defined by other humans. The sounds we make for one another are a primary source of vital information about our environment and our relationship to it. A slight change in volume or pitch in the human voice can carry an abundance of meaning, and can make the difference between a warning and an invitation, between information about danger, or dinner, or a chance to help create the next generation. It is important to be particularly attentive to the normal range of fundamental notes and harmonics in a human voice, which is rooted in the mid bass to midrange frequencies, from about 100Hz to around 2,500Hz. This sensitivity to minute changes in this range affects how we hear music. The ear is tuned to sounds in the midrange frequencies. A change in amplitude or frequency in this range is much more noticeable than the same, or even larger changes in the very high and very low frequency ranges.
The midrange tones have the greatest impact on the definition of any musical sound. Some guitar amps have a presence control that boosts or cuts the mids Around 1,000 Hz, and some home audio amplifiers and speakers are designed to boost the midrange in order to affect the quality of recorded music. There is actually some debate among audiophiles about this. There has been a trend, ever since the 1980s, of reducing the midrange tones on a guitar signal, or scooping the mids, to get a sound with relatively exaggerated bass and treble. Some people love it, others find it difficult to listen to, or, in some situations, to even hear properly. It is a very specialized tone that is really only used for a few related genres of metal, and it works, arguably, only if you play loud enough to hear the remaining mids. The scooped-mids sound exists as a defining feature of several distortion pedals designed specifically for metal guitarists. Other dirt boxes put the controls in your hands with the knowledge that the midrange tones define your sound more than anything else. This is something to be aware of when shopping for your next dirt box, or successfully auditioning for that really loud metal band.