Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 6/25/2013
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connections from a power amplifier to more than one loudspeaker. The downside is that you
have exposed pins on cables with fairly high-voltage signals, which is a safety concern. Usually,
the safety issues can be avoided by making connections only when the system is powered off.
The other potential problem with the banana connector is that it's very easy to insert the plug into
the jack backwards. In fact, a backwards connection looks identical to the correct connection.
Some banana connectors have a little notch on one side to help you tell the positive pin from the
negative pin, but the more reliable way for verifying the connection is to pay attention to the
colors of the wires. You‟re not going to break anything if you connect the cable backwards.
You‟ll just have a loudspeaker generating the sound with an inverted polarity. If that‟s the only
loudspeaker in your system, you probably won't hear any difference. But if that loudspeaker
delivers sound to the same listening area as another loudspeaker, you'll hear some destructive
interaction between the two sound waves that are working against each other. The banana
connector is also used with electronics measurement equipment such as a digital multi-meter.
Figure 1.35 Banana plug connector
The speakon connector was designed by the Neutrik connector company to attempt to
connector. This all but eliminates the potential for shorting the pins on a high-voltage signal. The
solve all the problems with the other types of loudspeaker connections. The connector is round,
and the panel-mount version fits in the same size hole as a panel-mount XLR connector. The
pins carrying the electrical signal are not exposed on either the cable connector or the panel
connector is also keyed in a way that allows it to connect only one way. This prevents the
polarity inversion problem as long as the connector is wired up correctly. The connector also
locks in place, preventing accidental disconnection. Making the connection is a little tricky if
you‟ve never done it before. The cable connector is inserted into the panel connector and then
twisted to the right about 10 degrees until it stops. Then, depending on the style of connector, a
locking tab automatically engages, or you need to turn the outer ring clockwise to engage the
lock. This connector is good in the way it solves the common problems with loudspeaker
connections, but it is certainly more expensive than the other options. Within the speakon family
of connectors there are three varieties. The NL2 has only two signal pins, allowing it to carry a
single audio signal. The NL4 has four signal pins, allowing it to carry two audio signals. This
way you can carry the signal for the full-range loudspeaker and the signal for the subwoofer on a
single cable, or you can use a single cable for a loudspeaker that does not use an internal passive
crossover. In the latter case, the audio signal would be split into the high and low frequency
bands at an earlier stage in the signal chain by an active crossover. Those two signals are then
fed into two separate power amplifiers before coming together on a four-conductor cable with
NL4 connectors. When the NL4 connector is put in place on the loudspeaker, the two signals are
separated and routed to the appropriate loudspeaker drivers. The NL4 and the NL2 are the same
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