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70.7V and 100V SYSTEMS
Several voltage standards have been put in place regarding so called 'constant voltage
systems.' In the United States, 25V, 70.7V and 100V are common. Occasionally 140V
systems can be found, usually in very large venues such as racetracks, where the need to
overcome cable resistance by scaling-up the voltage becomes extremely important. In Europe
and Asia most constant voltage systems use the 100V standard; in the USA the 70.7 voltage
standard is most often utilized.
A VERIS 2 loudspeaker equipped with the optional autoformer will support both the 70.7V and
100V standards. The same screw terminals are used for both voltage standards, but the
power level of the tap is different, depending on whether the amplifier voltage is 70.7V or
100V. Note that on the rear input panel, the power levels above the horizontal line refer to a
70.7V system, while the power levels below the line refer to a 100V system.
A 100V system will produce twice the power at a given tap, as that of a system run at 70.7
volts. This can be verified by the simple Ohm's Law calculation E
voltage applied, Z is the load impedance, and W is the power expressed in Watts. Assuming a
load impedance of 50 ohms, we can see that 70.7 x 70.7 / 50 = 99.97 and that 100 x 100 /
50 = 200.
Therefore, when scaling up from 70.7V to 100V the power will double; when
scaling down, the power will halve.
CAUTION: Be sure to carefully observe polarity when wiring your loudspeakers. If
one loudspeaker is wired with the opposite polarity from another loudspeaker, acoustic
cancellation will occur if the loudspeakers share the same acoustic space. The result
will be less power output than if only one loudspeaker were used by itself.
TIP: When using the barrier strip for wiring, we recommend that you first terminate
the wire with a plated copper crimp-type spade lug, using moderate to heavy pressure
on the crimp tool. When the spade lug is tightened firmly on the barrier strip it will
form a gas-tight connection resistant to corrosion. Be careful not to over-tighten the
barrier strip screws, as they can sheer off under too much torque. This is the
recommended method of wiring for fixed installations, especially those that may be
exposed to inclement environmental conditions.
WIRING NL4 TYPE CONNECTORS
The following diagram shows how connections are made to an NL4 type of loudspeaker
connector. Terminations may be soldered, or made by means of their built-in screw and
pressure clamp. If using the pressure clamp, it's important to tighten it fully, then to wait
about ten minutes (longer is better), then to tighten it again. This is because copper wire
flows under pressure. After initially tightening the screw clamp, some minutes later the screw
will no longer be as tight due to the effect of the compression on the copper. Typically, only
one cycle of "tighten – wait – re-tighten" is required for a secure connection.
Figure 6: NL4-Type Connector
Note: Pins 2+ and 2- are not used in VERIS 2 loudspeakers.
DANGER: When wiring the amplifier(s) to the loudspeaker(s), always power-down the
amplifier(s) and disconnect their 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 power levels.
NEUTRIK SPEAKON™
CONNECTOR – NL4FC
VERIS 2 – Operation Manual - Page 18
2
/Z = W, where E is the
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