6
The power handling listed for each EAW transducer is a good indicator of the size of the
amplifier that will safely drive it to full output under most conditions. Amplifier selection
is dependent upon the load presented at the amplifier output. Each doubling of loud-
speaker quantity doubles the required amplifier power. In other words, two KF750s LF
drivers in parallel require an amplifier channel capable of at least 1200 W into 4 Ohms.
Driving four KF750 LF drivers in parallel (2 ohm impedance) can eliminate one amplifier
per rack. While many amplifiers are capable of driving 2 ohm impedances, low frequency
performance may be compromised. Amplifier manufacturers should be consulted to
determine the power available and distortion present when driving low impedance loads.
5.4.4
LOUDSPEAKER CABLE
The resistance of the loudspeaker cable should be as low as possible to keep cable power
losses low and to maintain an acceptable damping factor, particularly for low frequency
transducers. The loudspeaker load will significantly affect both of these factors. For a
given wire size and length of loudspeaker cable, a greater impedance load will cause a
greater power loss and lower damping factor. This fact must be considered when paral-
leling multiple loudspeakers on an amplifier channel.
The following are minimum recommended wire sizes for loudspeaker cabling.
(AWG = American Wire Gauge; MWG = Metric Wire Gauge):
Length of Cable
Nominal Load
Cable Wire Gauge
0 - 50 ft / 0 - 15 m
8 ohms
14 AWG / 16 MWG
50 - 100 ft / 15 - 30 m
8 ohms
12 AWG / 20 MWG
100 - 200 ft / 30 - 60 m
8 ohms
10 AWG / 25 MWG
Over 200 ft / 60 m
8 ohms
Not recommended
0 - 50 ft / 0 - 15 m
4 ohms
12 AWG / 20 MWG
50 - 100 ft / 15 - 30 m
4 ohms
10 AWG / 25 MWG
Over 100 ft / 30 m
4 ohms
Not recommended
0 - 50 ft / 0 - 15 m
2 ohms
10 AWG / 25 MWG
Over 50 ft / 15 m
2 ohms
Not recommended
5.5
Array Design
5.5.1
APPROPRIATE VERTICAL CONFIGURATION
Each KF750 loudspeaker provides well-controlled 35° x 35° coverage. KF755 loudspeakers
provide the same coverage, but are vertically asymmetrical. The vertical pattern lies within
0° and -30° with maximum output at -12.5°. EASE data is available for KF700 Series
loudspeakers to aid designers in creating an appropriate vertical configuration for a fixed
installation.
KF700 (F) Series touring versions require evaluating each venue independently to determine
the most appropriate configuration for a given performance. The first step in designing an
array is designing a column that will vertically address the audience. It is easiest to determine
column requirements by examining a cross-section of the venue with appropriate stage
location and array trim height. It is easy to see that audience members seated at varying
vertical angles are seated in vastly different acoustical environments. These vertical zones
require an integrated array column targeted at seamlessly covering the entire venue from
a single location. The primary key to delivering uniform response and SPL to the entire
venue is appropriate use of different KF700 Series models to address the complex
cross-section of most venues. This topic is covered in detail in the KF700 Series Touring
Usage Guide.
11' 8"
90"
11' 8"
90"
