ABSTRACT
A volume control is the most essential knob on a preamplifier – in fact the unhappily named ‘passive preamplifiers’ usually consist of nothing else but a volume control and an input selector switch. Volume controls in one guise or another are also freely distributed on the control surfaces of mixing consoles, examples being the auxiliary sends and the faders. The simplest volume control is a potentiometer. These components, which are invariably called ‘pots’ in practice, come with various control laws, such as linear, logarithmic and antilogarithmic. The closeness of approach to an ideal logarithmic law is not really the most important characteristic of a volume control – spreading out the most-used middle region is more useful. All the active volume controls, including the otherwise superior Baxandall configuration, give a gain law that falls very rapidly in the bottom tenth of control rotation.
