JBL 2446-H, 2446-J Brochure

Professional Series

Key Features:

100 watts continuous program
at 500 Hz

150 watts continuous program at
1 kHz and higher

Coherent Wave™ phasing plug design
for increased high-frequency output

100 mm (4 in) pure titanium dia­phragm with radial-rib topology
and patented three-dimensional
diamond pattern suspension

100 mm (4 in) edgewound
aluminum voice coil

49 mm (2 in) throat exit diameter

2446H/J

Compression Driver

The model 2446H/J is a professional
quality high-frequency compression
driver that incorporates JBL’s newly­developed Coherent Wave phasing
plug as well as a pure titanium dia­phragm with radial ribs and patented
three-dimensional diamond pattern
suspension.

The Coherent Wave phasing plug
assembly consists of four die-cast
annular aperture structures of con­stant path length to provide m-phase
combining of diaphragm output at the
driver’s exit. This optimized configu­ration allows coherent summation of
acoustical power up to much higher
frequencies than afforded by earlier
designs.

The diaphragm design includes

JBL’s exclusive three-dimensional
diamond pattern surround1 which
reduces membrane stresses in the
diaphragm support structure and
extends diaphragm life. The depth of
the diamond pattern is closely con­trolled during the manufacturing
process to provide predictable fre­quencies for the 2nd and 3rd normal
resonance modes and for the basic
suspension resonance mode. The
diaphragm also incorporates a series
of embossed radial reinforcing ribs
that increase diaphragm stiffness. This
diaphragm, when combined with
the Coherent Wave phasing plug,
increases the 2446H/J’s output in
the 5 kHz to 20 kHz range.

Specifications:

Throat Diameter: 49 mm (2 in)

Nominal Impedance: 2446H 8 ohms

Minimum Impedance: 6 ohms (H), 12 ohms (J) @ 5 kHz

DC Resistance: 4.3 ohms (H), 8.5 ohms (J) ± 10% @ 25°C

Power Capacity¹: 100 W continuous program above 500 Hz

Sensitivity: 111 dB SPL, 1 W @ 1 m on-axis on horn²

Nominal Efficiency: 30% (500 Hz to 2.5 kHz)

Frequency Range: 500 Hz to 20 kHz

Recommended Crossover:

Diaphragm: 0.05 mm (0.002 in) pure titanium

Voice Coil Diameter: 100 mm (4 in)

Voice Coil Material: Edgewound aluminum ribbon

Flux Density: 1.9 T (19,000 gauss)

Bl Factor: 12.7 (H) N/A

Positive voltage to black terminal gives diaphragm motion toward the phasing plug

Dimensions: 235 mm (9¼ in) diameter

Mounting: Four ¼-20 threaded holes, 90° apart on 101.6 mm (4 in) diameter

Net Weight: 13.8 kg (30½ lb)

¹Continuous program is defined as 3 dB greater than continuous pink noise and is a conservative expression of the
transducer’s ability to handle normal speech and music program material Continuous pink noise power ratings are tested
with pink noise input having a 6 dB crest factor, with a high-pass filter set at the specified lower limiting frequency for two
hours duration.

²Sensitivity measured with 1 W input at 1 m distance on axis from the mouth of a horn with a Q of 6.3 averaged in the 2 kHz
octave band.

³As specified by recognized standards organizations, sensitivity is measured with the driver coupled to a terminated tube.
The JBL sensitivity rating represents the SPL in a 25 mm (1 in) terminated tube, using a 1 mW input signal (0.126 V into 16
ohms) swept from 500 Hz to 2.5 kHz. The sensitivity with a 1 W input would be 30 dB greater

JBL continually engages in research related to product improvement. New materials, production methods, and design
refinements are introduced into existing products without notice as a routine expression of that philosophy. For this
reason, any current JBL product may differ in some respect from its published description but will always equal or exceed
the original design specifications unless otherwise stated

2446J 16 ohms

150 W continuous program above 1 kHz

118 dB SPL, 1 mW on plane-wave tube³

500 Hz or higher, 12 dB/octave minimum

18 (J) N/A

131 mm (5 in) depth

¹U.S. Patent #4,324,312. Foreign patents pending.

2446H/J Compression Driver

High temperature voice coil former materials and adhe­sives enable the 2446H/J to handle extremely high power
levels over extended periods of time. The voice coils
themselves are identical to previous JBL models, so that
impedance and network matching will be the same. After
manufacture, the frequency response of each driver is
tested for conformity to JBL’s rigid performance standards.

The model 2446H/J is ruggedly constructed to withstand
the rigors of both fixed and transportable commercial
applications. All cast parts and machined tolerances are
held to the same levels traditionally associated with JBL
designs. The JBL manufacturing process also permits the
use of rim centered rather than pin mounted diaphragms,
for instant interchangeability and ease of field service.

Architectural Specifications:

The compression driver shall consist of a ferrite magnet structure
with all magnetic assembly parts machined from cast or extruded
billet stock. The phasing plug shall be assembled of concentric horns
of equal path length to eliminate case cancellations, and it shall be
coupled to a tapered throat. The diaphragm shall be 0.05 mm (0.002
in) pure titanium pneumatically drawn to shape and embossed with
radial reinforcing ribs to increase stiffness. High frequency response
shall be controlled through the use of a three-dimensional suspension
structure. The voice coil shall be edgewound aluminum ribbon of not
less than 100 mm (4 in) diameter, operating in a magnetic field of not
less than 1.9 tesla (19,000 gauss).

Performance specifications for a typical production unit shall be as
follows: Measured sensitivity with a 1 mW input on a 25 mm (1 in)
terminated tube, averaged from 500 Hz to 2.5 kHz, shall be at least 118
dB SPL. Measured sensitivity with a 1 W input at a 1 m distance on axis
from the mouth of a horn with a Q of 6.3 averaged in the 2 kHz octave
band shall be at least 111 dB SPL. As an indication of electromechanical
conversion efficiency, the Bl factor shall be at least 18 newtons per
ampere. Frequency response, measured on a terminated tube, shall
be flat within ± 1 dB from 500 Hz to 3.3 kHz, with 6 dB/octave roll-off
above that point. Nominal impedance shall be 8 [16] ohms and power
capacity shall be at least 100 watts normal speech or music program
material.

The compression driver shall be the JBL Model 2446H[J]. Other
drivers will be considered for equivalency provided that submitted
data from a recognized independent test laboratory verify that the
above performance specifications are met.

Response on JBL 2380A Flat-Front Bi-Radial® Horn

Frequency response of the 2446J coupled to a JBL 2380A Flat-Front
Bi-Radial® Horn, measured on-axis at a distance of 1 meter with a
l-watt (4.0 V rms) input in a reflection-free environment, with
impedance vs. frequency curve. A horn with a pure exponential flare,
such as typical radial horn designs, will exhibit greater high-frequency
output on-axis at the expense of lose angular coverage.

Response on Plane Wave Terminated Tube

Frequency response and impedance modulus of Model 2446J
coupled to as 49 mm (2 in) tube, with sensitivity referred to a 25 mm
(1 in) tube. This is the power response of the transducer, and is the
frequency response that will be obtained on a true full-range constant
directivity horn design, such as JBL’s 2360 series of constant coverage
Bi-Radial® horns.

JBL Professional
8500 Balboa Boulevard, P.O. Box 2200
Northridge, California 91329 U.S.A.

A Harman International Company

SS 2446H/J
CRP 5M
10/96