Professional Collection Manual
4
6. 70V/100V System
70/100-Volt systems are advantageous when the design calls for multiple speakers from
the same amplifier and/or long-distance wire runs.
These Professional Collection 70V/100V Pendant Speakers feature multiple taps off the
transformer, adjusted by a rotary switch on the front face of the speaker. The higher the
wattage selected, the more output will be generated by the speaker.
Please note, 70V is common in the U.S. while 100V is the common voltage internationally,
especially in Europe. A simple calculation is used to determine how many speakers can be
driven on a single amplifier channel. First, for safety purposes, it is recommended to make
the calculations based on 80% of the amplifiers rated power.
• For example, a 500-watt amplifier would safely deliver 400 watts of usable power (500 x
0.8 = 400). Now it is simply a matter of dividing 400 by the tap setting of the speakers.
• For example, if the speakers are set at a 15W tap, the amplifier would be capable of
driving 26 speakers per channel. At a 30W tap that would be 13 speakers. At a 60W tap that
would be 6 speakers and so on.
As you can see, if you need coverage over a wide area and it requires numerous speakers,
a 70V/100V system presents a tremendous advantage. However, it should be noted that
the higher the wattage tap, the higher the fidelity and the greater SPL that can be delivered
from each speaker. Therefore, it is best to determine the total number of speakers needed
and set the taps as high as possible
WITHIN
the amplifier’s power output rating
.
As mentioned, the rotary switch used to adjust the tap setting is located on the front face
of the speaker. For this reason, it is best to leave the grilles off until all of the tap settings
have been properly adjusted.
The following table lists the power tap settings for each model. The same settings are
reflected on the rotary switch on the front face of speaker (reference image below).
NOTE:
There is an 8Ω setting for both voltages that bypasses the transformer entirely.
Use
caution to avoid this setting when connected to a 70V/100V amplifier as this can destroy
the loudspeaker.
The tap setting determines how much wattage each speaker will draw from the amplifier.
When daisy-chaining multiple speakers: add the combined wattages of all tap settings, to
determine the wattage draw on the amplifier.
The combined total wattage should
NEVER
exceed the wattage rating of the amplifier.
