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4. Spaceframe?
A rigid aluminum
outer structure
that distributes
lifting stress along the entire sides,
enabling pull tests of up to 25,000 Ibs. with no failure or
structural
deformation...impossible
with
traditional
wooden enclosures.
5. Linear
Dynamics
Aperture?
Contoured
subwoofer
ports
that
virtually
eliminate
high-level
turbulence
found in traditional
subwoofers...giving
an
8dB improvement at full output over standard ports. The
overall subwoofer system provides 3dB areater outout
than conventional
subwoofers.
meaning only one half
the number
are required
for equivalent
acoustical
output when compared to conventional
units.
ANY ONE OF THESE TECHNICAL
ADVANTAGES
WOULD
GIVE
A
SOUND
SYSTEM
A
_ _COMPETlTlVE
EDGE.
HLA COMBINES
THEM
ALL.
POWER RECblMENDATIONS:
HIGH
OUTPUT
= FEWER AMPLIFIERS
Due to its high electrical-to-acoustical
power conversion
efficiencies,
HLA' s
reduced
amplifier
power
needs
further lighten the overall system weight of an HLA-
loaded truck. In fact, a small system of 8 (eight) 4895 3-
way
units
and 4 (four)
4897
subwoofers
can be
powered
by
as
few
as
5
(five)
high-powered
professional
dual-channel
power
amplifiers.
This
is
nearly one-half
the number of amplifiers
required by
some competitive,
traditional
loudspeaker
systems to
achieve the same acoustical output.
The result? Fewer speaker units and fewer amplifier
racks required for a given SPL (Sound Pressure Level),
resulting
in a lower overall
truck axle weight.
For
example:
astern Weight 8~ Amplifier Reauirements,
Ecal
Total # of enclosures-
(8) 4895 3-way, (4) 4897 subs
Total power amplifiers-
(5 dual-channel power amplifiers)
Total speaker weight-
(2,880 Ibs.)
*Suggested power levels: HF (High Frequency), 150-200 watts
MF (Mid Frequency), 300-500 watts
LF (Low Frequency), 500-700 watts
Subwoofer, 600-l ,000 watts
4
SPEAKER
UNIT SIZE
The HLA enclosures
are engineered
for the highest
possible audio performance
and maximum acoustical
advantage. To provide this, the high-output waveguides
require specific path lengths and horn mouth areas.
This includes a design goal of true, controlled-coverage
response to 100H.z in the Model 4897 3-way system.
This characteristic
eliminates the traditional " hole" in the
frequency response between the mid/high box and the
subwoofer
found
in
many
other
systems.
The
subwoofer requires the same shape and size so that it
can be suspended
together
as part of the array if
desired, and to provide the required internal working
volume and port area for high output levels.
Clearance
is provided
within
the
Spaceframe
to
accomodate
directional
tilting
of
this
aimable
waveguide
in the Model 4895 3-way unit. It has an
engineered tilt angle of 15 degrees. This can be used to
direct sound up or down depending
on the cabinet' s
orientation.
This
provides
optimum
coverage
with
minimum
overlap,
dramatically
improving
speaker
system intelligibility.
It also sets the physical size of the
frame.
..J
POWER AMPLIFIER
SUGGESTIONS,
TYPICAL
The 4895 3-way unit uses 16-ohm transducers,
allowing four transducers
in each bandpass to be driven in parallel.
The 4897 Subwoofer uses two 8-ohm transducers.
Figure 1
Bandpass
JBL
crest
Crown
QSC
HF
600: 150W/ch., S
7001: 2OOW/ch., S
2400: 2OOW/ch., S
1.8: lGOW/ch., S
MF
1200: 300W/ch., S
9001: 500W/ch., S
3600: 4OOW/ch., S
4.0: 400W/ch., S
LF
1200: 8OOW/ch., B
9001: 500W/ch., S
5000: 5OOW/ch., S
3.4: 850W/ch., B
/-
SUB
750: lOOOW/ch., B
9001: llOOW/ch.,
S
3600: 800W/ch., S
4.0: 800W/ch., S
Notes: ' s' = stereo mode. ' B' = bridged mode.
&
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