6. Important Terms
A term used to describe the route an audio signal takes within a mixer, most commonly applied to aux sends. Pre-fade means that the aux send isn't affected by the main fader level (and sometimes also the EQ) - this is usually used for monitor and headphone mixes, giving the performer a mix that is independent of the FOH or main mix. Alternatively, post-fade signals are affected by the fader level, and this is normally used for effects sends where the level of the effect or 'wet' signal therefore follows the level of the untreated or 'dry' signal.
Balanced or Unbalanced
Describes the manner of a signal's transfer from source to destination. Balanced signals require a balanced output at one end and a balanced input at the other end in order deliver their advantage, which is the substantial reduction of any noise induced in the cable. This is achieved by sending the audio signal down two separate cores of the cable, one of which has its phase inverted. At the other end, the inverted signal is re-inverted and combined with the untreated signal, at which stage any interference that has been picked up in the cable will be cancelled out, leaving the original signal in-phase, at twice the strength, and without any interference. Balanced connections are usually made either with XLR or Tip-Ring-Sleeve (TRS) jack connections. A balanced TRS jack connection will have two rings on the connector as opposed to an unbalanced one which has just one. TRS jacks are sometimes known as a 'stereo' jacks, as they can also be used to transmit an unbalanced stereo signal. The main problem when using unbalanced connections is that of combating interference, and although less of an issue in smaller applications, unbalanced cables used in environments demanding longer cable runs can suffer from undesirable buzzes and hums. Almost all microphones and mic inputs are balanced, although line level inputs and outputs vary.