Equalization (EQ) Explained
today we thought we’d talk a little technical and focus on EQ! Our human range of hearing is called the audio spectrum. The audio spectrum consists of frequencies, which are measured in Hertz (Hz) and each frequency has a number assigned to it. Our human range of hearing is from 20Hz to 20000Hertz or 20 Khz where 1000hertz is equivalent to 1KHz.
Every audible sound sits within the frequency range of human hearing. These sounds are not just a single frequency, but a complex combination of frequencies that work together and create that sound or timbre (character) of the instrument. These frequency combinations is what help us perceive if the instrument is a piano or guitar playing the same frequency (in music we call it pitch).
Every instrument will have what is called the fundamental frequency (the loudest frequency and what determines it’s pitch) as well as a combination of other frequencies are called harmonics (sometimes overtones).
When you are learning to work with EQ and training your ears; we suggest that you utilize an EQ that has a spectrum analyser. This is a visual representation of the frequency content that is in your audio signal; and will really help you make good EQ decisions.
High pitched sounds like drum cymbals and hissing sounds usually have higher numbers; so they are at the top end range of the audio spectrum and lower pitched sounds like kick drums and bass guitars have lower numbers and are found at the bottom end range of the audio spectrum.
As audio engineers, we have taken the whole audio spectrum and divided it into different frequency ranges. Then, we’ve given those frequency ranges (also called frequency bands) a name; and then further described what they typically sound like. the audio spectrum is defined by groupings of frequencies called frequency bands.
These are labeled as:
1. Sub Bass,
2. Bass (low) & Bass,
3. Midrange (low, mid, upper),
4. High and
5. Very High Frequency.
In addition to naming each frequency band; we use words to describe the type of sound associated with each frequency band. Words like ‘warmth’ or Edge’; even ‘air’.
Very simply, EQ can be thought of as a level control for frequency. They use specialized filters that influence the volume of specified frequencies or a range of frequencies within the audio spectrum.
EQ is mainly used to adjust (shape) the tone and character (timbre) of a sound; by either boosting or cutting frequencies. You can’t completely change a sound by using EQ; you can only cut, reduce, remove or exaggerate (boost) frequencies already present in the sound. Equalizers are the essential tools used to achieve clarity, depth, tonal balance, and presence.
There are different types of filters and some terms specific to equalizers you need to know. We’ve asked Bronwen from www.rapponine.net to take us through EQ filters in a video tutorial!
Boost your creative knowledge!
The R-loops team!