Jbl 2404 h brochure

Page 1

UBL

Ultra-High
Frequency Transducer

Professional Series

Key Features:

> BisRadial K ConstantoCoverage
horn design

Constant 100° x 100° dispersion
from 3 kHz to 20 kHz

40 Watts continuous program
>3 kHz to 2115 kHz response

Annularoring diaphragm ferrite
motor structure

44 mm (1in) edgewound
aluminum ribbon voice coil

D 105 dB sensitivity, 1 W, 1 m (33 ft)

Designed for use as an ultraohigh
frequency driver in multioelement,
full range loudspeaker systems, the
JBL Model 2404H delivers an uni
matched combination of wide, tightly
controlled dispersion, extended free
quency response, high power capac
ity, and high efficiency

One key to this outstanding perforo
mance lies in the unique geometry of
the drivers BisRadial horn Develo
oped with the aid of the latest compus
ter design and analysis techniques, the
horn provides constant coverage from
its recommended crossover point of
3 kHz to beyond 20 kHz The BisRadial
compound flare configuration mains
tains precise control of the horns
Wide 100° x 100° coverage angle, and
the horns rapid flare rate dramatically
reduces second harmonic distortion.
The uniform coverage of the horn is
illustrated by the detailed polar data
and the isobar (constant sound pres
sure) contours included in this specie
fication sheet The polar curves of the
2404 exhibit softoedge pattern characo
teristics, due to the gradual dropsoff of
level with increasing offoaxis angler

Specifications:

Nominal Impedance: 8 ohms

Minimum Impedance: 7.2 ohms @ 3 kHz

Power Cnpaciry: 40 warrs continuous program at 3 kHz or higher,
12 dB/octave slope

Sensitivirya: 105 dB SPL (1 w, 1 in)
Frequency Response ( i 3 dB): 4 kHz to 19 l 12
Usalile Frequency Ran e ( . 10 dB): 3 kHz to 21.5 kHz

Coverage Angles: (Included angle between (i an down points, rated
over 3.15 kHz to 20 kHz)

Horizontal Angle: 100 ( + 47, , 10)°

(Flange mounting holes on top and bottom)
Vertical Angle: 100 ( + 42. , 14)°

(Flan e rnounrin holes on ri hr and left)
Directivlty Factor (Q): 6.8 (+ 1.5, . 2.3)

(Avcra ed over 315 kHz to 20 kHz)
DirecuVity Index (Di): 83 (+ 0.9, . 1.8)

(Averaged over 3.15 kHz to 20 kHz)
Recommended Crossover: 3 kHz or higher

(\xi'irri minimum 12 dB/ocrave slope)

Diaphra on 0.05 mm (0.002 in) Aluminum alloy
Diaphragm Diameter: 44 mm (1 in)
Voiee Coil Diameter: 44 mm (1 in)
Voice Coll Material: Edgewound aluminum ribbon
Mugneue Assembly Weight: 1.9 kg (4.1 lb)
Flux Density: 1.75 *r (17,500 gauss)
Foree Factor (B1): 5.25 N/A
Positive voltage ro black terminal gives forward diaphragm niou'on
Dimensions:
Flan e Hei ht: 130 mm (5.12 in)
Flange Width: 130 mm (5.12 in)
Depths:
Overall: 128 mm (5 in)
Behind Battle: 96 mm (3.76 in)
In Front of Baffle: 32 mm (1. in)
Baffle euronr Diameters: 122 mm (4in)
Net Weiglir: 2.27 kg (5 lb)
snippin \Xei ht: 2.72 kg (6 lb)

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Page 2

D 2404H Ultra-High Frequency Transducer

The coverage pattern of the BieRadial horn provides
precise pattern control and excellent frequency response
even at extreme oblique offeaxis angles (offeaxis both
horizontally and vertically). This behavior is illustrated in
this specification sheet with polar data taken at an oblique
angle of 45° in addition to the usual horizontal and vertie
cal polar curves. Additional data on the directional charace
teristies of the 2404 is illustrated in 10 kHz octave band
width isobar contours. These contours represent the
sound pressure distribution in the front hemisphere of
the horn. The contours show the excellent symmetrical
softeedge coverage that the BieRadial horn provides

Coupled to the horn is a constant area phasing plug and
an annular ring diaphragm ferrite motor structure.

The phasing plug maintains constant phase and amplie
tude. The annular voice coil diaphragm is pneumatically
formed of fatigueeresistant aluminum and utilizes an optie
mally constructed voice coil former and the latest in high
temperature adhesive technology to substantially increase
the drivers power capacity. A ferrite magnetic structure
provides a high flux level for extended response and max
imum efficiency while maintaining traditional JBL
tolerances in assembly and manufacture.

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Architectural Specifications:

The transducer shall have a measured sensitivity (SPL at l m with a
1 \W input swept from 3 kHz to 20 kHz) ofa least 105 dB on axis. One
axis frequency response measured under free field enndirinns at a (liSr
tance of 1 m (3.3 ft) or more shall extend from 3 kHz to 20 kHz.

Horizontal and vertical dispersion shall be a constant 100° x 100°
from 3 k [7. to 20 kHz when measured at the 6 dB down points relative
to oneaxis frequency response characteristics using "soctave hand
pink noise as the signal source. Nominal impedance shall be 8 ohms
and power capacity shall he at least 40 watts normal program material.

The transducer shall have a maximum flange size of 130 mm x 130
mm (5.12 in x 5.12 in) and a depth of 128 mm (5 in) and weigh nor less
than 11 kg (5 lb). The horn shall be iniection molded structural foam
polycarbonate.

All magnetic assembly parts shall be machined from east or
extruded billet stock.

Voice coil diameter shall be 44 mm (13 in)y operating in a magnetic
field \vhose flux density measures ar least 1.75 tesla (17,500 gauss).
Voice coil wire shall be aluminum, milled to a ribbon then wound by
hand on its edge and mated to an anodized aluminum diaphragm.

The transducer shall be _]BL Model 2404M.

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Funu-ncy Hz

Frequency response and impedance.

Frequency response of the 2404, measured on axis at a distance of
1 meter with 1 watt (2.83 V RMS) applied, in a reflectionefree envie
ronment, with impedance vs frequency curve. Unit free standing
(without baffle).

SPL :13 (ramps)
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Fnuuency M1

Horizontal off-axis response.
l'lorizontal ()ffeaxis response taken at 15 degree intewals out to 90
degrees off axis.

SPL as («2mm

moo mm moon
Frequency Hz

Vertical off-axis response.
Vertical offraxis response taken at 15 degree intervals out to 90
degrees off axis.

350

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rrequencyH:

Beamwidth ( . 6 dB) vs Frequency.