Ground lift

In sound recording and reproduction, ground lift or earth lift is a technique used to reduce or eliminate ground-related noise arising from ground loops in audio cables. It may also increase or decrease noise from other sources.^[1] Activating the ground lift on a particular piece of equipment opens the connection between the equipment ground and the shielding conductor of audio cables attached to the equipment, leaving those cables grounded only at their opposite end.

If all pieces of equipment are tied to a common ground reference without establishing ground loop, no current flows in the ground conductors and cable shields, and no noise is introduced into signal circuits. In applications such as sound reinforcement for a concert, however, it is difficult to ensure all equipment shares a common ground reference.^[1]