An Equaliser is a device that grants precise control over the tonal characteristics of an audio signal by amplifying or attenuating specific frequency bands. It is the primary tool for shaping sound, allowing engineers to correct imbalances, such as removing muddy low frequencies or adding brightness to vocals. Equalisers come in several architectures to suit different needs. Graphic equalisers provide a visual representation of the spectrum with fixed frequency sliders. Parametric equalisers offer the most flexibility, allowing the user to sweep through frequencies and adjust the bandwidth (Q) of the cut or boost. Shelving equalisers, often found on hi-fi systems, affect all frequencies above or below a certain point continuously. While related to filters, equalisers are generally more versatile for musical tonal shaping.