JBL 2405-H Brochure

F

1

Ultra-High

Professional Series

Key Features:

b 40 watts continuous program
b

6.5

kHz to 21.5 kHz response

b

44

mm

(13/4

in) aluminum ribbon

voice coil
b 105 dB sensitivity, 1 W, 1 m (3.3 ft)
b 90” x 25” dispersion at 16 kHz

The 2405H is designed for use as
the ultra-high frequency driver in a
wide-range, multi-element loud­speaker system. It features a unique
combination of extended frequency
response, high efficiency, and wide
dispersion pattern.

Frequency response extends
smoothly from 6500 Hz to beyond the
range of human hearing. A unique
diffraction horn provides horizontal
dispersion that is greater than 90
degrees at 16 kHz and 65 degrees at
20 kHz - far wider than conventional
direct radiating loudspeakers of com­parable efficiency, regardless of their
size. Vertical dispersion pattern is 25
degrees at 16 kHz and 20 degrees at
20 kHz. Dispersion pattern measure­ments are determined from the points
where level is 6 dB down from the on­axis value using S-octave bands of
pink noise as the signal source. For a
given power input, the 2405H pro­duces an exceptionally high acoustic
output, converting a l-watt input into
a sound pressure level of 105 dB at a
distance of one meter, At typical
monitoring levels, such efficiency
allows the 2405H to re-create intense
high frequency onsets and transients
with outstanding clarity and accuracy.

The 2405H utilizes an anisotropic
strontium ferrite magnet, manufac­tured using a wet-pressed form­ing process. The newly developed
magnet material provides the highest
residual flux density, maximum
energy product, and most suitable
coercive force for alnico conversion
to ferrite. These characteristics yield

.e -a c “a

Frequency Transducer

Specifications:

Horn Mouth Diameter:

Nominal Impedance: 8 ohms

Minimum Impedance, 8 ohms @ 6.5 kHz

DC Resistance: 6.25 ohms 210% @ 25°C

Power Capacity’:

Sensitivityz:

Nominal Efficiency: 5%

Frequency Response ( + 3 dB):

Frequency Range ( - 10 dB):

Dispersion3 (6 dB down points, 140” horizontal x 40” vertical at 10 kHz

%-octave band, pink noise):

Directivityz: Factor (Q): 10

Recommended Crossover:

Diaphragm:

Voice Coil Diameter: 44 mm (13/4 in)

Voice Coil Material: Aluminum ribbon

Magnetic Assemblv Weight:

Flux Density,

Bl factor. 5.25 N/A

Positive voltage to black terminal gives forward diaphragm motion.

MOUNTING INFORMATION:

Baffle Cutout Diameter:

Dimensions

Net Weight,

1 Continuous program power is defined as 3 dB greater than continuous pink noise and is a conservarive expression of the

transducer‘s

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.
2Averaged from 7 kHz to 20 kHz, 2.83 ARMS input.
SWidest dispersion is in rhe plane perpendicular to the length of the horn opening.

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 respecr from its published description, but will always equal or

exceed the original design specifications unless otherwise stated.

ability to handle typical speech and music program material. Continuous pink noise power ratings are tested

79 mm x 18 mm (1.125 x 0.725 in)

40 watts continuous program above 6 kHz
105 dB SPL, 1 W, 1 m (3.3 ft)

7 kHz to 20 kHz

6.5 kHz to 21.5 kHz

90” horizontal x 35” vertical at I6 kHz
65” horizontal x 30” vertical at 20 kHz

Index (DI): 10 dB
7 kHz or higher, 12 dB/octave minimum

0.056 mm (0.0022 in) aluminum alloy

1.9 kg

(418

lb)

1.75 T (17,500 gauss)

79 mm (3i/~ in)
121 mm (43/4 in) diameter

95 mm (33/q in) depth
2 3 kg (5 lb)

b, 2405H Ultra-High Frequency Transducer

better temperature stability, resistance to demagnetiza­tion, reduction in weight over typical ferrite material, and
give the highest performance on an actual production
basis. By precise machining, a flux density of 1.75 tesla
(17,500 gauss) in the voice coil gap is realized.

The diffraction horn assembly is die cast of solid
aluminum. Internally, the annular voice coil diaphragm is
pneumatically formed of fatigue-resistant aluminum alloy.
Wire used in the 44 mm

(13/4

in) voice coil is aluminum,
milled to a thin ribbon. This process places a maximum
amount of conductor in the magnetic gap for optimum
efficiency and transient response.

The use of high-temperature voice-coil former materials
and adhesives has improved the power handling and rug­gedness of the driver. The voice coil itself is identical to
the previous alnico magnet model, so that impedance and
network matching will be the same.

Architectural Specifications:

The transducer shall have a maximum diameter of 98 mm (3’/8 m)
and a depth of 83 mm (3% in) and weigh not less than 2.3 kg (5 lb).
The dlffraction horn shall be die cast of aluminum and the magnetic
circuit will weigh not less than 1 8 kg (4 lb ).

Voice co11 diameter shall be 44 mm (1% in), operatmg m a magnetic
field whose flux density measures at least 1.75 T (17,500 gauss). Voice
coil wire shall be milled alummum ribbon

The transducer shall have a measured sensltlvity (SPL at 1 m (3.3 ft)
with a 1 W input, swept from 7 kHz to 20 kHz) of at least 105 dB on
axls On-axls frequency response measured under free field condo­tions at a distance of 18 meters (6 ft) or more shall extend from 7 kHz
to 20 kHz within plus or minus 3 dB. Horizontal dispersion shall be
uniform at 45 degrees off-axls at 16 kHz and 30 degrees off-axis at 20
kHz, when measured at the 6 dB down pomts relative to on-axls fre­quency response characteristics using %-octave band pink noise as the
slgnal source

Nominal Impedance shall be 8 ohms and power capactty shall be at
least 20 watts when driven by pink noise, band-limited from 6 kHz to
20 kHz.

The transducer shall be JBL Model 2405H

Beamwidth vs. Frequency

200
180

100

8”:

70

60
SO

40

30

/

20

I ,

I

I

I

I I I

10

2 3 5

Vertical dispersion of the 2405H.

T

I

j__-

I

Frequency, kHz

10

-l-L

Polar response of the 2405H in the horizontal plane,
measured with %-octave band pink noise in a free-field
environment.

I

I

20

r

JBL Professional

8500 Balboa Boulevard, PO. Box 2200
Northridge, California 91329 U.S.A.

H

A Harman

International

Company

W9110M
P1058