4. The Earth Lift
Most modern DI boxes have an earth lift switch. This removes the earth from one end of the
BalancedTerm used to describe a system of audio connection that employs phase inversion noise cancellation. Using two signal wires and an earth, the audio is split and phase inverted in the second signal wire. On reaching the destination the second signal is re-inverted and combined with the first. Any electromagnetic interference is picked up equally by each signal cable and so will be cancelled out by the phase inversion. A balanced line requires balanced equipment at both ends.balanced
line, and can be used to solve ground loop problems, which typically manifest themselves as a nasty buzz or
HumUnwanted sound of a specific frequency constantly present in an audio signal, often caused by interference from AC mains power and therefore occurring at 50Hz or mathematically related frequencies.hum
. Ground loops are very common when theres a lot of other
AudioGenerally used to mean "sound"; technically it describes periodic fluctuations of air pressure or electrical energy at frequencies and amplitudes within the human range of hearing; sound, or electrical energy that represents sound; acoustic, mechanical, or electrical frequencies corresponding to normally audible sound waves. audio
gear and/or lighting in use. However, its important to remember that the earth lift cannot be used if phantom power is required (see below).