Electro-Voice HP420 User Manual

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

HP420

Constant-Directivity

Horn

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.

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 Rθ(Q):

47.5 (average 1.25 kHz to 20 kHz)

Directivity Index Di:

16.8 dB
10 log Rθ, (average 1.25 kHz to 20 kHz)

Lowest Recommended Crossover Frequency:

500 Hz

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)

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Figure 1: Dimensions

Directivity

The axial directivity factor Rθ (formerly Q) of the HP420 horn
was computed at each one-third-octave center frequency from
the horizontal/vertical polars. The graph in Figure 2 illustrates
this data over the range 500 Hz to 20 kHz. The axial frequency
response of the HP420 with a particular driver is in close
correspondence to that driver’s power response above 500
Hz.

Beamwidth

A plot of the HP420’s 6-dB-down total included beamwidth
angle is shown in Figure 3 for each one-third-octave center
frequency. The horizontal beamwidth is maintained at 40°
(+20°, -10°) over the range of 650 Hz to 20 kHz. Vertical
beamwidth control occurs only above 2.2 kHz because of
the relatively short vertical dimension of the horn’s mouth.

Figure 3: 6-dB-Down Beamwidth versus FrequencyFigure 2: Directivity vesus Frequency

USA 12000 Portland Ave South, Burnsville, MN 55337, Phone: [phone], FAX: [phone]
Canada 705 Progress Avenue, Unit 46,Scarborough, Ontario, Canada, M1H2X1,Phone: [phone], FAX: [phone]
Germany Hirschberger Ring 45, D94315, Straubing, Germany, Phone: [phone], FAX: [phone]
France Parc de Courcerin, Alle Lech Walesa, Lognes, 77185 Marne La Vallee, France, Phone: [phone], FAX: [phone]
Australia Unit 23, Block C, Slough Business Park, Slough Avenue, Silverwater, N.S.W. 2128, Australia, Phone: [phone], FAX: [phone]
Hong Kong Unit E & F, 21/F, Luk Hop Industrial Bldg., 8 Luk Hop St., San PO Kong, Kowloon, Hong Kong, Phone: [phone], FAX: [phone]
Japan 5-3-8 Funabashi, Setagaya-ku, Tokyo, 156-0055 Japan, Phone: [phone], FAX: [phone]
Singapore 3015A Ubi Rd 1, 05-10, Kampong Ubi Industrial Estate, Singapore 408705, Phone: [phone], FAX: [phone]
Mexico Av. Parque Chapultepec #66-201, Col. EI. Parque Edo. Mex. 53390, Phone: [phone], FAX: [phone]
UK 4, The Willows Centre, Willow Lane, Mitcham, Surrey CR4 4NX, UK, Phone: [phone], FAX: [phone]
Africa, Mid-East 12000 Portland Ave South, Burnsville, MN 55337, Phone: [phone], FAX: [phone]
Latin America 12000 Portland Ave South, Burnsville, MN 55337, Phone: [phone], FAX: [phone]

www.electrovoice.com  Telex Communications, Inc.  www.telex.com

© Telex Communications, Inc. 02/2001
Part Number 38109-952 Rev A

For customer orders, contact the Customer Service department at

For warranty repair or service information, contact the Service

For technical assistance, contact Technical Support at 866/78AUDIO

Please refer to the Engineering Data Sheet for warranty information.

Specifications subject to change without notice.

U.S.A. and Canada only.

800/392-3497 Fax: [phone]

Repair department at 800/685-2606