Seasons Outdoor Collection™
System Design
70V / 8 Ω System
70-volt systems are advantageous when the design calls for multiple speakers from the
same amplifier and/or long-distance wire runs. The 70V/8 ohm Rock Collection speakers
feature multiple taps off the transformer adjusted by a rotary switch on the bottom side
of the speaker. The higher the wattage selected the more output will be generated by the
speaker.
The switch can be rotated to adjust to the following settings:
Model
Position 1
2
3
4
5
OSR65
70v
3.7W 7.5W 15W 30W
8 Ω
OSR85
70V
7.5W 15W 30W 60W
8 Ω
OSR8SUB
70V
15W
30W 60W 120W 8 Ω
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.
As you can see, if you need coverage over a wide area and it requires numerous speakers, a
70Vsystem 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 is to be used to adjust the tap setting.
Note
: There is an 8 Ω setting that bypasses the transformer entirely. Use caution to avoid
this setting when connected to a 70V amplifier as this can damage the speaker.
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