Electro-Voice Cobreflex IIB User manual

Cobreflex IIB
Folded
Sectoral Horn
General Product Description
The Cobreflex IIB is an exponentially flared, reflex design
for use in public address, paging, and voice warning systems.
This reflex construction results in both compactness and
high efficiency when combined with appropriate compression
drivers.
The patented (patent # 2,751,996) folded design features
two separate air columns in a single assembly that virtually
eliminates high-frequency phase cancellation present in
re-entrant designs.
The 80-degree horizontal by 60-degree vertical dispersion
pattern is beneficial in many applications requiring a wide
coverage pattern. Furthermore, excellent loading is
maintained to a low-frequency cutoff of 250 Hz.
The Cobreflex IIB is constructed from a high-impact
acrylonitrile butadiene styrene (ABS) with an ultraviolet
inhibiting grey paint finish. A serrated positive-lock “U”
mounting bracket is provided for maximum mounting flexibility
and ease of installation.
Architects’ and Engineers’ Specifications
The horn shall be of the reflex type featuring two separate
air columns within the single assembly. It shall produce a
horizontal beamwidth of 80-degrees and a vertical
beamwidth of 60-degrees at 2 kHz. In addition, it shall
provide useful acoustic loading at all frequencies above 250
Hz.
The horn shall be constructed from a high impact acrylonitrile
butadiene styrene (ABS) and finished with an ultraviolet
inhibiting grey paint.
Specifications:
Horizontal Beamwidth:
80° @ 2 kHz (see Figure 2)
Vertical Beamwidth:
60° @ 2 kHz (see Figure 2)
Directivity Factor Rθ (Q):
9.1 @ 2 kHz (see Figure 3)
Usable Low-Frequency Limit:
250 Hz
Construction:
High impact acrylonitrile butadiene styrene (ABS) with
ultraviolet light inhibiting grey paint finish. Positive-lock painted
steel U-bracket.
Mechanical Construction of Driver:
Threaded metal throat insert to accommodate a screw-in driver
with a throat opening of 0.7 inch to 1.0 inch diameter and a
standard 1 3/8"-18 thread.
Dimensions:
Height: .......................................................... 23.5 cm (9.3 in.)
Width: ......................................................... 47.0 cm (18.5 in.)
Depth: ......................................................... 26.0 cm (10.3 in.)
Net Weight: .............................................................. 2.3 kg (5.1 lb)
Shipping Weight: ..................................................... 3.0 kg (6.7 lb)
Recommended Horns:
ID30C-8 7110XC ID30C-16 1824S
ID30CT 1828R ID60C-8 1828T
ID60C-16 1829 ID60T ID75
COMMERCIAL
A serrated, positive-lock “U” mounting bracket shall be affixed
to the bell by self-locking nuts and shall provide orientation
adjustment in all three planes.
The horn shall possess a throat of 1.91 cm (0.75 in.) diameter
and shall be provided with a 1 3/8"-18 thread for the mounting
of a compression driver. The horn shall be 23.5 cm (9.3 in.)
high, 47.0 cm (18.5 in.) wide and 26.0 cm (10.3 in.) deep. It
shall weigh no more than 2.3 kg (5.1 lb).
The horn shall be the Cobreflex 11B reflex horn.

© Telex Communications, Inc. 02/2001
Part Number 38109-857 Rev A
U.S.A. and Canada only.
For customer orders, contact the Customer Service department at
800/392 3497 Fax: [phone]
For warranty repair or service information, contact the Service
Repair department at 800/685 2606
For technical assistance, contact Technical Support at 866/78 AUDIO
Please refer to the Engineering Data Sheet for warranty information.
Specifications subject to change without notice.
Polar Response
The directional characteristics of the Cobreflex IIB, with driver
attached, were measured by running a set of horizontal/ vertical
polar responses, in a large anechoic chamber, at each
one-third-octave center frequency. The test signal was one-
third-octave pseudo-random pink noise centered at the indicated
frequencies. The measurement microphone was placed 6.1 m (20
ft) from the horn mouth, while rotation was about the waveguide
geometric apexes. These axes of rotation are quite close to the
apparent (acoustic) apexes across the frequency range of
measurement. Errors attributable to the slight differences between
the geometric and acoustic apexes are reduced to an
inconsequential level by the relatively long, 20-foot measuring
Figure 1.
Cobreflex IIB Polar Response
Figure 2.
Cobreflex IIB Beamwidth vs. Frequency
Figure 3.
Cobreflex IIB Directivity Factor
and Directivity Index vs.Frequency
distance. The horn was suspended freely with no baffle. The polar
plots shown in Figure 1 display the results of these tests.The center
frequency is noted on each plot. The wider plot on each chart is the
horizontal polar (–) and the narrower plot is the vertical polar
(– – –).
Beamwidth
A plot of the Cobreflex IIB’s 6-dB-down total included beamwidth
angle is shown in Figure 2 for each one-third-octave center
frequency.
Directivity
The axial directivity factor R
θ
(formerly Q) of the Cobreflex IIB horn
was computed at each one-third-octave center frequency from the
horizontal/vertical polars and is displayed in Figure 3.
USA 1 000 Portland Ave South, Burnsville, MN 55337, Phone: [phone], FAX: [phone]
Canada 705 Progress Avenue, Unit 46,Scarborough, Ontario, Canada, M1H X1,Phone: [phone], FAX: [phone]
Switzerland Keltenstrasse 11, CH- 563 IPSACH, Switzerland, 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 3, Block C, Slough Business Park, Slough Avenue, Silverwater, N.S.W. 1 8, Australia, Phone: 61/ -9648-3455, FAX: 61/ -9648-5585
Hong Kong Unit E & F, 1/F, Luk Hop Industrial Bldg., 8 Luk Hop St., San PO Kong, Kowloon, Hong Kong, Phone: 85 - 351-36 8, FAX: 85 - 351-33 9
Japan -5-60 Izumi, Suginami-ku,Tokyo, Japan 168, 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- 01, Col. EI. Parque Edo. Mex. 53390, Phone: (5 ) 5358-5434, FAX: (5 ) 5358-5588
UK 4, The Willows Centre, Willow Lane, Mitcham, Surrey CR4 4NX, UK, Phone: [phone], FAX: [phone]
Africa, Mid East 1 000 Portland Ave South, Burnsville, MN 55337, Phone: [phone], FAX: [phone]
Latin America 1 000 Portland Ave South, Burnsville, MN 55337, Phone: [phone], FAX: [phone]
www.electrovoice.com • Telex Communications, Inc. • www.telex.com