While every individual is different, humans can generally perceive sounds that vibrate between 20 and 20,000 cycles per second, or Hertz (abbreviated Hz). The rate of a sound’s vibration is called its frequency. We typically describe slower vibrations as lower and faster vibrations as higher. This perceived lowness or highness has an effect on timbre. For example, we seldom describe a bass as “crystalline” or a high piccolo as “boomy.”

Range is particularly crucial to the fine-tuning of timbre done by audio engineers. One of the most important skills required of an audio engineer is the ability to identify how the unique range and sonic characteristics of each instrument contribute to the overall sound of a recording, and then to adjust these to make the recording more effective. This is often done with a tool called an equalizer or EQ, which can boost or cut specific frequency ranges to affect the timbre of a single sound, a group of sounds, or an entire song.

To assist in doing this work, audio engineers often think of the range of human hearing as divided into smaller frequency ranges. Each of these ranges is home to fundamental pitches as well as other audible characteristics. For example, a piano sound that we think of as “the A below middle C” will have its fundamental sound in the low end at roughly 220Hz and will also have overtones in the low-mid (around 440Hz), mid (around 880Hz), and higher ranges. The percussive beginning of the sound will also include many other frequencies . Understanding what each range contributes to the timbre of a sound is crucial to making a beautiful recording of an acoustic instrument, balancing a recording of an ensemble, and shaping the sound of an overall recording.