Community WET II - Operation and Installation Manual - Page 14
CONNECTING THE AMPLIFIER TO THE LOUDSPEAKER
All WET II loudspeakers come with an attached input cable that is coated with an EPDM rubber jacket, twelve
feet in length and colored to match the finish of the enclosure. The cable enters the enclosure through a
waterproof gland nut. The other end of the cable is un-terminated.
A typical installation method is to bring the cable into a waterproof Junction Box equipped with a waterproof
gland nut. Connections within the J-Box may be made with barrel-type crimp connectors, wire nuts, solder
and heat-shrink, or terminal strips. We recommend using barrel-type crimp connectors that are crimped
with a forged crimp tool (such as Klein 1005) or a ratcheting tool (such as Klein T1720), as this method, when
properly executed, results in a gas-tight connection that is quick and easy to accomplish.
DANGER:
When wiring the amplifier(s) to the loudspeaker(s), always power-down the amplifier(s) and
disconnect its AC Mains plug(s). Many modern, high-power amplifiers can deliver enough voltage and
current to cause a harmful or lethal electric shock. Shocks from very low frequencies, such as kick drums,
can cause the human heart to stop beating at relatively low voltage levels.
WARNING:
After wiring the amplifier(s) to the loudspeaker(s), first power-up all devices that are upstream
of the amplifier, such as mixers, equalizers, compressor/limiters, etc.,
before
powering-up the amplifier.
This is to avoid passing any clicks or pops that may originate in the upstream devices to the loudspeakers.
The amplifier should initially be powered-up with its gain controls turned all the way down. After making
sure that a continuous signal is present, such as a CD playing, slowly raise the level of the gain controls to
establish that the wiring has been installed correctly. Only then should the loudspeaker be operated at
normal output levels.
Impedance and Combining Loudspeakers
Loudspeakers of identical type may be wired together on the same amplifier. This forms a parallel circuit.
When two loudspeakers are wired in parallel, the nominal impedance of the circuit will divide in half. For
example, if two 8 ohm loudspeakers are wired in parallel, the result will be a 4 ohm load and the power from
the amplifier will be divided equally between both. If four 8 ohm (or two 4 ohm) loudspeakers are wired in
parallel, the result will be a 2 ohm load and again, the power will be divided equally among the
loudspeakers.
If an uneven number of loudspeakers are wired in parallel, you can use the following formula to calculate
the resultant impedance, where Z is the impedance in ohms: 1/Z + 1/Z +1/Z = 1/Zt = Z.
Here is an example: 1/8 + 1/8 + 1/8 = 1/.375 = 2.666 ohms.
Unequal Impedances
It’s important to note that when wiring loudspeakers of unequal impedances in a parallel circuit, the power
will
not
be divided equally among each loudspeaker.
For example, if an 8 ohm and a 4 ohm loudspeaker are wired in parallel the resultant load will be 2.6 ohms.
The 4 ohm loudspeaker will draw twice as much power from the amplifier than the 8 ohm loudspeaker. In
this example, if the amplifier is capable of producing 1800 watts into the 2.6 ohm load of the paralleled
loudspeakers, the 4 ohm loudspeaker will receive 1183 watts while the 8 ohm loudspeaker receives 591
watts.
