All About The Audio Spectrum And Sound Frequency

Understanding the audio spectrum is essential to successfully mix music. In this guide you will learn about the seven frequency bands in the audio spectrum and get helpful tips on how to EQ them.

close up of an analog synthesizer with patch cables

The audio spectrum is the range of frequencies that humans can hear, from the lowest bass to the highest pitches.

Let’s get nerdy for a quick second.

Sound travels through the air via sound waves, and not all waves have the same length. Low notes have long waves and high notes have shorter ones.

The rate at which a wave repeats is its frequency, which we measure in hertz (Hz). The audible frequency range at which humans can hear is generally between 20 Hz to 20,000 Hz.

All of the instruments and notes used in your music have frequencies and will line up somewhere on the audio spectrum. This is what the audio spectrum looks like when a bass drum hits:

A bass drum shown on the audio spectrum in FL Studio's Fruity Parametric EQ 2

A bass drum shown on the audio spectrum in FL Studio’s Fruity Parametric EQ 2

The Seven Audio Frequency Bands

It’s useful to split the audio spectrum into seven distinct frequency bands. Those frequency bands are:

Audio Frequency Bands
Sub Bass aka Low Bass (20 – 60 Hz)

Bass (60 – 250 Hz)

Lower Mid (250 – 500 Hz)

Mid (500 Hz – 2 kHz)

High Mid (2 – 4 kHz)

Presence (4 – 6 kHz)

Brilliance (6 – 20 kHz)

Let’s go through each of these seven bands to take a look at their defining characteristics and learn how to EQ them.

Sub Bass (20 – 60 Hz)

Sub bass frequencies illustrated on the audio spectrum

The lowest of the lows, the sub bass frequency range is filled with extremely deep pitches that people tend to feel more than hear. When you are in a club or at a concert and can feel the bass drum pounding in your chest, that’s the sub bass range at work.

Producers use sub bass to add extra power to kick drums and basslines. This is especially popular with hip-hop, house, drum and bass, and dubstep.

Bass drum, bass guitar, bassoon, pipe organ, and bass trombone have frequencies that begin in the sub bass region.

EQing Sub Bass: Boost the sub bass to increase the power behind your drums and bassline, or cut it to decrease the power. If you put too much emphasis on the sub bass your music will tend to sound muddy.

Bass (60 – 250 Hz)

Bass frequencies illustrated on the audio spectrum

This frequency range forms the first truly distinguishable notes that will carry a song. All of those groovy basslines you hear? That’s the bass section of the audio spectrum. The bass frequency band enhances the overall richness of a song and adds power to virtually any instrument that falls within its range.

Cello, guitar, french horn, male vocals, and extremely low female vocals all are instruments that begin in the bass region.

EQing Bass: This is a fun section to play around with as it enhances the overall weight of your music – if you want your song to sound a little fatter, go ahead and add a little to this range. Don’t boost too much or you’ll run the risk of making your music sound boomy. Cut too much and you’ll make your sound artificially thin.

Lower Mid (250 – 500 Hz)

Lower mid frequencies illustrated on the audio spectrum

The lower mid-range forms the core frequencies for guitars, piano, and vocals. Indeed, the vast majority of instruments span this section of the audio spectrum. The lower mid frequencies give warmth and weight to your sound.

Most female vocals begin in this region.

EQing Lower Mids: Boosting too much will make your track sound muddy or congested. If you don’t have enough emphasis here your instruments will sound thin and weak.

Mid (500 Hz – 2 kHz)

Mid range frequencies illustrated on the audio spectrum

The mid range is critically important as it determines the extent which an instrument will sit at the forefront of your mix.

EQing Mids: The mid is a notoriously tricky part of the audio spectrum for producers to mix. There are normally a variety of issues that pop up here regarding competing frequencies need to be sorted out. When adjusting frequencies, be aware that if you boost too much your instruments will start to sound tinny, and if you cut too much your instruments will lose all presence.

High Mid (2 – 4 kHz)

High mid frequencies illustrated on the audio spectrum

The upper midrange frequencies give a little more edge to guitars and vocals. They add to the aggressiveness of these instruments which may be desirable, but too much can quickly turn to harshness.

EQing High Mids: It’s important to be careful when EQing the high mids. If this range is increased too much it can add a lisp into vocals and make it harder to understand sounds with “m”, “b”, and “v”. Boosting too much at the 3 kHz range can cause listening fatigue, which no producer wants in their music. That said, cutting instruments and slightly boosting vocals at the 3 kHz point can increase the clarity of vocals without having to decrease instrument levels.

Presence (4 – 6 kHz)

Presence frequencies illustrated on the audio spectrum

Presence is what helps us clearly hear instruments and vocals.

EQing Presence: Boosting through this range can make music (and vocals) seem closer to the listener. By cutting at the 5 kHz mark you’ll make a sound more distant, which can also be a useful effect.

Brilliance (6 – 20 kHz)

Brilliance frequencies illustrated on the audio spectrum

Brilliance also helps enhance the clarity of sounds and adds “air” or “sparkle” to your instrument.

EQing Brilliance: You can enhance the overall clarity of vocals by boosting in this audio range. Do not boost too much however, as doing so can make any sibilance (“s” sounds in the vocals) stand out. Too much brilliance can also make your music sound artificial or even fizzy. If you’d like to flatten out your sound a bit, be sure to cut in this range.