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impedance. Note that very few amplifiers are stable under 2-ohm loads, so that is
usually not an option.
On the other hand, with a constant voltage system, you consider first the RMS
output wattage of the amplifier. This should be reduced by 20% to compensate
for insertion loss. For example, if using a 100-watt amplifier, the total load from
speakers should not exceed 80 watts.
Each individual speaker on a given channel is set to a value such that the total
does not exceed the rated power, less 20%. You do not need to worry about
making the total as close as possible to the limit; just ensure that the total does
not exceed the limit.
If all speakers are set to the same wattage value, they will all have the same
volume level. If one speaker is set to a higher wattage value, it will be louder
than the others, while a speaker set to a smaller value will be quieter than the
others. This allows you to compensate for the environment in which the speaker
is placed. For example, a speaker placed outside would need to be louder than a
speaker placed in a small room.
SPEAKER WIRING
Most constant voltage speaker installations will consist of
multiple speakers per channel, with all speakers
connected in parallel, as shown in the diagram to the
right.
To wire speakers in parallel, connect the first speaker to
the amplifier as normal. Connect the positive terminal on
the first speaker to the positive terminal of the second
speaker, and the negative terminal on the first speaker to
the negative terminal on the second. Repeat for each
additional speaker in the array.
