Specifications

19
CABLES AND CONNECTORS
C
ables and connectors are probably the most overlooked link in the
audio chain, and yet poor quality cables and/or faulty connectors are
frequently the cause of major audio problems.
There are basically two kinds of connections used between audio
devices: balanced and unbalanced. A balanced
connection requires a
cable with two wires (one for the “hot” signal and one for the “return”)
enclosed by a shield of metal foil, braid, or mesh. The shield intercepts the
random electrical signals that bombard the cable from various sources and
drains them to ground. Together, the wires and the shield keep the audio
signal free of interference. For applications in which cables will be frequently
disconnected and coiled up for storage, choose those which use braid or
mesh shielding; these are more resistant than metal foil to cracks or tears
due to flexing, which can cause electrical shorts.
An unbalanced
connection utilizes a cable with a single wire surrounded
by a shield, but in this case the shield has to do double-duty. It carries the
“return” portion of the audio signal as well as protecting the wire inside from
electrical interference. This method is not nearly as effective as the balanced
type, so unbalanced audio cables are easily affected by florescent light
fixtures, some types of dimmer switches, and other audio or electrical cables
that may be nearby.
Balanced audio connections are generally used with low-impedance
equipment, while unbalanced connections are used with high-impedance
equipment. You may encounter exceptions, however. As a rule, balanced
connections will offer much cleaner, noise-free performance.
You may be wondering, “How will I know if a connection is balanced or
unbalanced without cutting the cable open to look?” Fortunately, you can
make a pretty accurate guess by looking at the connectors on each end of
the cable. As you’ve probably found out, there are several different kinds of
connectors found on audio equipment, and some are better than others.
Today, the most popular connector for professional microphones and
audio equipment is the XLR
connector. Male XLR connectors have three
pins, and are used for signal output; female XLR connectors have three
sockets, and are used for signal input. The XLR connector is very rugged,
rarely bends or breaks off while connected, and most versions lock together
securely so that accidental unplugging is unlikely. A cable that has an XLR
connector at both ends almost certainly indicates a balanced connection.
XLR connectors are found on both low- and high-impedance microphones.