Community R-Series Installation/Operation Manual for Models R.5 and R.25 — Page 18
E L E C T R I C AL I N S TAL L AT I O N AN D S AF E T Y
DANGER:
The output voltage and current of audio power amplifiers are a shock hazard especially
in 70-volt and 100-volt distributed systems. To minimize the risk of electric shock from loudspeaker
connecting cables, confirm that the power amplifiers are turned “off” before connecting loudspeaker
cable to the loudspeaker or amplifier. Always follow local electrical codes and proper electrical
safety procedures.
Inputs
R-Series input is via an attached 16 Gauge SJOW cable rated for outdoor use. This cable is approximately 12
feet (4m) in length. The Specifications section shows the input connections for each model. Note that some
70V/100V models have selector switches in place of the multi-wire cable.
Ensure the connection you make to this cable is suitably weather-sealed. Do not remove the gland nut that
attaches the cable to the lower rear of the loudspeaker as this can compromise the weather integrity of the
enclosure.
Polarity
The white jacketed conductor is the positive or + signal wire and the black is the negative or – signal wire.
Positive voltage applied to the + wire produces positive acoustic pressure at the mouth of the loudspeaker.
Impedance
R.5 and R.25 loudspeakers are rated at 8-ohms nominal impedance. The impedance of transformer versions
(“T” suffix) depends on the tap chosen.
Recommended Amplifier Power
See the Specifications section in this manual for recommended amplifier power for each specific model. Using
an amplifier of less power than recommended will not allow maximum performance of the system and can
quickly damage the loudspeaker. The built-in DYNA-TECH protection circuitry (PowerSense DDP on model R1)
cannot detect clipping nor will it detect when less than the recommended power is used. Correspondingly, using
an amplifier of more power than recommended can result in overdriving the loudspeaker with the potential for
damaging the drivers and/or the protection circuitry.
Recommended Cable Type and Size
The resistance of the cable between the loudspeaker and the amplifier affects the performance of the
loudspeaker. Cable with too high a resistance can cause power losses and impair low frequency performance by
reducing the electrical damping factor. To minimize these problems it is desirable to keep the total cable
resistance under 0.2 ohm. For lengths over 100 feet the wire gauges needed to meet this requirement are
usually not practical to use for both physical and cost reasons. Therefore 10 Gauge is recommended as the
most practical gauge for those situations. Use the following table to select the proper wire gauge. Either
stranded or solid conductors are acceptable although cable with stranded conductors can be easier to work with.
The run length for both conductors has been figured into the total resistance. Note the lower the gauge number
the larger the wire size.
INSTALLATION
