10
CHAPTER 3
For example, cascading 10 700-HPs produces an input
impedance of 1000 ohms (10 kOhms divided by 10). The
source equipment should have an output impedance of
100 ohms or less. This is also true when connecting 700-
HPs in parallel (loop out) with other self-powered Meyer
Sound loudspeakers, for example, MILO, M3D, M2D or
MSL-4.
TIP:
If abnormal noises such as hiss and
popping are produced by the subwoofer,
disconnect the audio cable from the subwoofer. If
the noise stops, then most likely the problem is not
with the subwoofer. Check the audio cable, source,
and AC power for the source of the problem.
Meyer Sound LD-1A, LD-2 and LD-3 line drivers are
highly recommended when driving systems using multiple
loudspeakers. These line drivers, in addition to maintain-
ing signal integrity for long cable paths, offer independent
outputs and filters to help you integrate 700-HP subwoof-
ers into your system.
NOTE:
For details on the 700-HP’s audio
input characteristics and amplification, see
Appendix B: Specifications.
700-HP INTERCONNECTIONS
The 700-HP utilizes two 4-ohm, 18-inch cone drivers.
These drivers feature lightweight neodymium magnet
structures and are rated to handle 1200 AES watts. Each
channel of the amplifier drives one low-frequency driver.
CAUTION:
All Meyer Sound loudspeakers
are shipped with the drivers in correct align-
ment. However, if a driver needs to be replaced,
make sure the replacement is reinstalled with the
correct polarity. Incorrect driver polarity impairs the
system performance and may damage the drivers.
The 700-HP is powered by the Meyer Sound HP-2/700
amplifier, a high-power two-channel amplifier. The ampli-
fier utilizes complementary MOSFET output stages (class
AB/H) capable of delivering 2250 watts total (1125 watts
per channel). All the specific functions for the 700-HP
such as crossover points, frequency and phase response,
and driver protection are determined by the control card
installed inside the amplifier.
CABLING
The 700-HP is available with two different cabling/con-
nection options. One is the Meyer Sound/VEAM cable
system, which combines AC power, audio signal, and
RMS network data into one heavy-duty cable with a single
matching connector per 700-HP cabinet.
The other (standard) system uses three separate cables
and connectors per cabinet for the AC line current, signal,
and RMS data. However, the three can be consolidated to
create a “multi-cable” by looming them together for quick
connection to each cabinet. This ensures no patching er-
rors and a minimum of discrete cables behind if the
700-HP cabinets are flown in an array.
A ring/stud fitting is provided on the rear of the 700-HP
loudspeaker to act as a strain relief for cabling. Using this
fitting will minimize the chance of cables being damaged
during installation. To utilize the strain relief fitting, insert
the signal, data, and AC connections into each loudspeak-
er as the array is being rigged (swag all cables under the
rain hood’s side flaps if installed), and tie the cables off to
the ring/stud fitting (Figure 3.3).
Figure 3.3. Tie cables off using the ring/stud fitting.
700-HP LIMITING
The 700-HP uses Meyer Sound’s advanced TruPower®
limiting. Conventional limiters assume a constant loud-
speaker impedance and therefore set the limiting thresh-
old by measuring voltage only. However, this method is
inaccurate, because the speaker’s impedance changes in
response to the frequency content of the source mate-
rial and thermal variations in the speaker’s voice coil and
magnet. Consequently, conventional limiters begin limiting
prematurely, which under-utilizes system headroom and
lessens the speaker’s dynamic range.
