For professional music recording and development, a variety of signal processors may be necessary. Signal processors are devices that intake analog signals such as voice and audio from instruments
, and can measure, convert, manipulate, filter, or compress these signals. This includes DI boxes, equalizers, audio converters, and compressors and gates.
A "direct injection” box is used to convert a high impedance signal, from an electric guitar or other instrument, into a low impedance signal that can be sent directly to a preamplifier
or mixing console. An equalizer is commonly used in pro audio
to adjust the balance of frequencies in a particular recording. Audio converters, as the name implies, convert audio from one signal to another. Available converter types include loop isolators, balanced to unbalanced, unbalanced to balanced, and unbalanced stereo line isolators. Compressors and gates are used to modify an audio signal, often to reduce the range of amplitude of the audio.