Using an equaliser is essential in music production. Equalisation is the process every producer uses to cut or boost a precise frequency range. It will make your music explode with the fatness of the low end, add depth to the body of the mid range and sparkle with high end detail. There are a wide range of equalisers at a sound engineer’s disposal but graphic, shelving and parametric equalisers are the varieties found in most recording studios.
Graphic equalisers are characterised by an array of slider parameters that can be used to cut or boost ranges throughout the frequency spectrum. These controls are spaced at intervals between 20 Hz to 20,0000 Hz, which is the scope of the human ear. At their most basic, graphic equalisers will have three to four bands while the more complex will have twenty or more sliders. The narrower the bandwidths on a graphic equaliser, the more accuracy it will have. They are better utilised to adjust the fidelity on a final mix than to manipulate specific sounds as there is no control over the bandwidth or filter shape of each parameter. As a music producer it is advised that you make small, detailed, alterations to the controls on your graphic equaliser and use them to subtly, fine-tune an overall piece of music.
These grant a music producer the ability to attenuate or boost frequencies from a fixed point. This means that if a sound engineer were to set the equaliser’s position to 40 Hz, for example, then everything above or below this ‘cut off frequency’ would be cut or boost. There are two types of shelving equalisers: High shelving EQs reduce or boost the volume of frequencies above the cutoff frequency while retaining the gain of everything lower. A low shelf filter adjusts all frequencies below the cut off point while ignoring sounds higher in the audio spectrum. Shelving equalisers are great for quickly eliminating or boosting any low end or high end signal. They can also be used creatively by automating the position of the cut off frequency to filter certain sounds into or out of a track.
Parametric equalisers are the most prevalent form of equalisation in music production, purely because they offer so much flexibility in terms of manipulating a sound. A multiband, parametric, equaliser such as the Channel EQ in Logic Pro, is made up of a range of adjustable frequency bands. They can be used to balance precise, frequency ranges throughout the audio spectrum. A sound engineer or producer will often use a parametric equaliser to meticulously sculpt a sound at a precise frequency. The precision of the range of frequencies that are adjusted is set using a parameter called the ‘Q-Factor’. Parametric equalisers often achieve their results using a range of different filter types.
High Pass/ Low Cut Filter: Eliminates sounds completely below the cut off frequency.
Low Shelf: Allows for the cutting or boosting of audio below a fixed point.
Bell EQ: Lets a producer boost or reduce a frequency bandwidth.
High Shelf: Allows for the cutting or boosting of audio above a fixed point.
Low Pass/ High Cut Filter: Eliminates sounds completely above the cut off frequency.