HP420
Constant-Directivity
Horn
General Product Description
The Electro-Voice
®
model HP420 is a wide-range,
flat-front, high-frequency, constant-directivity horn. The
horizontal angle is controlled over a frequency range
of 650 Hz to 20 kHz and the vertical angle is controlled
from 2.2 kHz to 20 kHz, both with unusual precision
and adherence to the intended angle. Furthermore,
excellent loading is maintained to a low frequency of
500 Hz.
The flat-front design makes the HP420 suitable for all
modern boxed and clustered systems. A special vaned
waveguide throat detail gives the HP420 unusually good
high-frequency control, vertically, when compared to
similar 2-inch-throat horn designs.
Architects’ and Engineers’ Specifications
The horn shall be of the constant-directivity type. It shall
produce a horizontal beamwidth (6 dB-down angle) of
40 degrees, deviating no more that 20 degrees from
this angle over the frequency range 650 to 20,000 Hz.
It shall produce a vertical beamwidth of 20 degrees,
deviating no more than 10 degrees from this angle over
the frequency range 2,200 to 20,000 Hz. In addition, it
shall provide useful acoustic loading at all frequencies
above 500 Hz.
The horn shall be of hybrid fiberglass-and-zinc
construction. The driver-mounting flange and initial
Specifications:
The following specifications are in accordance with or
exceed the AES Recommended Practice for
Specification of Loudspeaker Components Used in
Professional Audio and Sound Reinforcement
(AES2-1984; ANSI S4.26-1984).
Horizontal Beamwidth:
40° (+20°, -10°) (-6 dB 650 Hz to 20 kHz)
Vertical Beamwidth:
20° (+10°, -10°) (-6 dB, 2.2 kHz to 20 kHz)
Directivity Factor R
θ
(Q):
47.5 (average 1.25 kHz to 20 kHz)
Directivity Index D
i
:
16.8 dB
10 log R
θ
,
(average 1.25 kHz to 20 kHz)
Lowest Recommended Crossover Frequency:
500 Hz
throat section shall be constructed of die-cast zinc and
shall be integrally laminated into the fiberglass portion
of the horn.
The horn shall possess a throat of 4.92-cm (1.94in.)
diameter and its flange shall be provided with four ¼-20
clearance bolt holes on a 10.2 cm (4.0 in.) circle for the
mounting of the compression driver. The horn shall be
36.7 cm (14.4 in.) high, 61.0 cm (24.0 in.) wide, and
74.9 cm (29.5 in.) long. It shall weigh no more than 5.9
kg (13.0 lb).
The horn shall be the Electro-Voice model HP420
constant-directivity horn.
Construction:
Polyester resin and glass-fiber laminate integrally
molded to a die-cast zinc throat section. This hybrid
construction assures a rigid driver mount, accurate,
loss-free throat-wave transmission and low total weight
compared to horns of similar size.
Mechanical Connection of Driver:
Bolt on; standard 2" diameter throat, 5" diameter
mounting flange and four clearance holes for ¼" bolts
on a 4" diameter bolt circle.
Recommended Driver:
DH1A or DH2A
Weight:
5.9 kg (13.0 lb)
