What is BalanceD Anyway



What is balanced as a feature as used in audio jargon anyway—without getting into the nuance of things (yep, it’s very easy to get hung up in reductionism).

A balanced cable and signal, in its simplest form looks like floating railroad tracks, the positive, high, or A rail is identical to the negative, low, or A’ rail. And the virtual ground, the null, is established at an equal distance between them.

A balanced output, input, or interconnecting patch cable (yes there are other devices that can be characterized as balanced or not so balanced, loudspeakers for example can generally be thought of as balanced load) is when the signal and signal’s mate see the same electrodynamics characteristics. Breaking it down specific to audio’s beloved XLR-type connectorred components and cable we have:

  • Resistive qualities are the same on both positive and negative conductors, to use common words to note difference sides of the same coin.

  • Ground (be it real or virtual) is centered between signal—equal in distance and impedance to both positive and negative.

  • Capacitive and inductive qualities are also symmetrical (balanced) as seen from either side of signal.

  • Balanced is the above, or it’s not balanced, or it might be balanced but defined by bandwidth or usage, 20 to 20,000Hz for example.

Why is a balanced signal and transmission interesting?

  • Balanced signal and transmitting cable do not need a physical earth ground as the signal establishes its own virtual ground.

  • A well designed and build balanced source/signal/load will not act as an “antenna” and does not need external shielding, it simply does not pickup/receive environmental electromagnetic noise.

  • Generally, balanced electromagnetic signal and systems can send, transmit and receive signal for much longer distances with less loss of bandwidth or power over non-balanced topologies such as coax.

For your pleasure, puzzle on these:

Is the XLR a balanced connector?

Is the signal generated from a phono pickup balanced?

Can an RCA connector be used within a balanced system?

Why twist a balanced pair?

What the hell does HAM stand for anyway, if anything.

1966, name that landmark protest-heavy album?


Sean CaseyComment