Friends who have contact with the audio, I believe they have heard of the XLR connector, although it is not as popular as RCA Audio, but the two are a little different in nature. XLR is mainly used to transmit balanced audio, but also provides more different applications, RCA Audio is to transmit unbalanced audio, the former is specially designed, so that music can effectively reduce interference when transmitted over long distances, maintain better sound quality.
Over 70 years of history Analog, digital and diversified applications
The XLR terminal was invented by James H. Cannon, founder of Cannon Electric from Los Angeles, USA, so it is sometimes referred to as the Cannon plug. The original terminal was the “Cannon X” series, which became the “Cannon XL” series by adding a spring lock (Latch) in the 1950 version, and then wrapped with rubber on the terminal contact surface in the 1955 version, so the abbreviation of this terminal also became XLR. XLR terminals are divided into male and female, most commonly 3-pin designs, but due to the variety of XLR uses, from light control to low-voltage power supply, there are also designs with more pins, up to 10 pins, as well as thin plugs for the Mini XLR.
However, as a standard for transmitting balanced audio, the 3-pin XLR terminal is the most common, in addition to transmitting two-channel analog signals, it will also be used to transmit digital signals, using the standards set by the Audio Engineering Society (AES) and the European Broadcasting Union (EBU), so it is also called AES3, AES or AES/EBU.
XLRs that transmit audio most commonly use a 3-pin connection, with “male” and “female”.
There are also many different styles of XLR, AK’s KANN CUBE is equipped with a 5-pin Mini XLR terminal, which can be converted into two sets of 3-pin outputs using the adapter cable.
Positive, negative, ground 3-wire connections, inverting noise cancel each other
Many mid- and high-end front, rear stage, A/V combiners, CD players, as well as professional radio microphones and active listening speakers, are equipped with XLR terminals. XLR adopts a 3-pin 3-wire design, including positive, negative and ground 3 groups, positive wiring transmits normal audio, negative wiring transmits inverted (i.e., waveform reversed) audio.
The cleverly designed one is that the positive audio (e.g. + signal) and negative inverted audio (e.g. – signal), if noise is introduced during transmission due to interference from radio, Wi-Fi, fire bull, current, etc., both will add equal amounts of in-phase noise (e.g. + noise）。
The signal transmitted by XLR will reverse the negative signal at the receiving end and then superimpose it with the positive signal, so that the negative signal will change from the original “- signal + noise” to “+ signal – noise”, and then superimpose with the positive “+ signal + noise”, noise (e.g. – noise + noise) cancels each other out, leaving only twice as much audio (e.g. + signal + signal）。
In contrast, RCA Audio only uses two sets of wiring design of audio + ground, so the noise immunity will be weak. Therefore, RCA Audio is not suitable for long-distance transmission (e.g. >3 meters), while the XLR maintains its best sound quality over long distances.
XLR is more common in some intermediate and high-end equipment.
Noise introduced by RCA Audio during transmission. XLR cancels out the noise by superimposing the signal after the receiver signal is inverted.
Post time: Dec-07-2022