XLR Explained and the Basics of Pro Audio Plugs

The XLR plug is the standard for pro audio and videofirst, before the other pins make contact while the
applications. The plug itself is an electrical connector byXLRM is being inserted. Due to the fact that the
design. Not unlike the more ubiquitous RCA plug , whichground connection is made before the signal lines
used regularly with home audio and video electronics,make contact, XLR's can be plugged and unplugged
the XLR connector is different in several importantwithout interference from external signals, a common
ways.problem with RCA connections. There is some
Originally designed and manufactured by James h. thediscrepancy between various manufacturers between
connector was first called the "Cannon X," and afterswapping pin 2 (normal input) and pin 3 (inverting input),
the addition of a latch the "Cannon XL" and finally thebut this reflects nothing more than their own
"XLR" after having a rubber compound added to thepre-existing standards before any standards existed.
connectors.Pin 1 is exclusively the earthly return or ground pin, and
The 3-pin XLR is the most widely used, and is theoften soldered to the internal shell or case.
standard as a balanced audio connector forLastly, the XLRM male connector is used for output
professional microphones and connections betweenand the XLRF plug is used for input. So, a microphone
equipment. Other widely used configurations of thefor example will have the XLRM connector. Signal
XLR plug is the 4-pin XLR4, used with Clear-Com andcables will have XLRM at one end and an XLRF
Telex intercom headsets and as DC powerconnector at the other. Mixing boards and various
connectors for video and film cameras. XLR5 is themulti-track recording equipment pieces typically have
standard for DMX512 digital lighting control as well asXLRF inputs and XLRM returns which lead back to
dual element microphones and dual channel intercomthe stage, or to other components.
headsets. XLR6 is the standard connection for dualXLR connectors have been the standard in the
channel intercom belt-packs.professional recording and audio industry. XLR plugs
There are several now obselete configurations withare typically referred to as "balanced" and help reduce
additonal pins including the XLR-LNE mains powernoise interference, especially over long spans. Quality in
connector, which was identified by its red insulation andXLR cables varies greatly depending on the
shrouded pins, and has now been replace by themanufacturer, but for professional use please check
Neutrik PowerCon connector. Until recently, XLR3out Canare, Mogami and Neutrik.
connectors were also widely used with 2-conductorRecently, the advent of USB microphones that
loudspeaker cables, with either pin 2 or 3 as live (variesconnect directly to a PC or MAC have gained
depending on the manufacturer) and pin 1 as thepopularity. So far, USB microphones are primarily
earthly return. However, this turned out to beintended to be used as studio microphones, and live
dangerous to equipment and has since been replacedstage vocal microphones continue to use the standard
by the Neutrik Speakon connector.XLR connections.
XLRF connectors are made to connect the ground pin