EAW BH-215-LR User manual

Application
The BH-215-LR is designed for concert sound,
motion picture, high level playback, or any other sound
reproduction application where high output bass is required
down to the 40 Hz region. This vented horn is designed to
offer the finest performance available in applications
requiring crossover in the 500 to 800 Hz area. True
exponential design combined with unequaled quality
construction make this unit unparalleled in both sonic quality
and field durability.
Description
The BH-215-LR is built to the highest standards in
the professional sound industry, with careful attention to
design and construction. The unit was designed to eliminate
the problems associated with typical low horn efficiency.
This was achieved by using a mathematically correct true
exponential horn flare, as opposed to the typical radial or
semi-exponential horns available. This design improvement
provides increased efficiency and smoother response. To
provide deep bass from a reasonably sized package, vent
loading is provided to the driver chamber enabling the usable
low frequency response to extend down to 40 Hz. The
direct radiating of the drivers maintains smooth response to
800 Hz with a roll-off above this, for crossover in the
favorable 500 to 800 Hz region (critical in many two-way
systems). The unique phasing shelf between the drivers
minimizes the interaction of the drivers, also adding to the
upper response of the system.
The LF-383-R drivers that are standard in the BH-215-
LR (also available as BH-215-UL without drivers) provide
smooth response and excellent deep bass performance.
These units will reproduce bass below 100 Hz, with a
minimum of distortion where the driver is often called upon
to make up for the failing efficiency of the system by
handling more power through low frequency equalization.
The LF-383-R's will handle this demanding use with ease,
while many other drivers will produce exceptionally high
levels of distortion and, in many cases, have a severely
shortened service life.
Construction
The BH-215 is the unit that EAW's world famous
reputation for quality and durability in enclosure
construction is based on. Thousands of these units are in the
field throughout the world. Day in and day out they
continue to perform under the stress of heavy
professional use without failure or fatigue.
All exterior surfaces of the horn are fabricated
w
cross-grain laminated Baltic birch hardwood, with 18 plys
the inch. This multiple hardwood has a much higher stren
g
to weight ratio than ordinary plywood or particle bo
a
found in most other cabinets. In addition, the quality birc
h
an order in magnitude lower in panel resonances than ot
h
materials often used for bass horn construction, includ
i
fiberglass, compositeboard and simple plywood. The narr
o
band resonances which plague all competitive systems
a
created by cabinet walls or the horn flare sympathetic
a
vibrating with the audio signal. This robs efficiency and a
l
creates a series of narrow band steep dips in the syst
e
response. To virtually eliminate resonances, the inter
n
construction of BH-215LR's uses a combination
extensive internal bracing and specially develop
polyurethane reinforcing in the horn flare. This techniq
u
exclusive to EAW, provides total freedom from cabi
n
resonances over the operating range of the system.
The BH-215's superior construction adds to it's va
in portable applications. Not only does it haddto the so
u
quality, but also makes it significantly more durable under
t
rigors of road abuse. The BH-215LIR's all birch construct
i
and catalyzed polyurethane finish make it moisture, chemi
c
and scuff resistant. Many options, including wheels, han
d
and corners can be ordered for the BH-215-LR, but eve
n
basic form it is a unique combination of sonic performa
n
and physical durability for any application.

BH-215-LR Speciftations
Drivers: Two 380mm (15")
EAW LF-383R*
Nominal Frequency Range: 40 Hz to 1,000 Hz'
Frequency Response: 90 Hz to 800 Hz
±3 dB
Lowest Usable Frequency: 40 Hz -10 dB
Recommended Crossover
Frequency: 400 Hz to 800 Hz
Horn Gain: 8.5 dB
Horn Length: 21.5"
Mouth Area: 1,214 square inches
Sensitivity: 108 dB SPL 1w at 1m
Power Handling
Continuous Sine Wave: 400 wRMS
Program: 700 w
Maximum Continuous
Output: 134 dB 400 wat 1m
Nominal Dispersion: 80* Vertical
Horn Flare Rate: 90 Hz
Cabinet Material: Cross-grain laminated
Baltic birch Hardwood,
horn flare voids filled
with high damping fac-
tor polyurethane foam.
Cabinet Dimensions: 42" H x 36" W
x29 %"D
*For comprehensive driver information please see
LF383R data sheet.