The model 2421 IS a professional compressron
and flat response. of concentric cellations
determined
exponential
phasing
horns to minrmize
The aluminum
alloy diaphragm
of pre-
plug consists
phase can-
counteract
ring of pure silver surrounds the inductance
After manufacture, tested for conformity
reinforcement
and power capacity
fatigue. A new patented
consisting
free response
bending
dramond
depth of the diamond
The
to provide
resonance.
design and precise manufacturing
give the 2421 more consistent
to reduce
structure
2nd and 3rd normal resonance
modes and for the basic suspension
approximately
support
pattern is closely controlled
predrctablefrequenciesforthe
This suspension
of a three-
pattern, has been designed
stresses In the diaphragm
high frequency
twice the power capacity
control
response
of its predecessor.
the frequency
response
to rigid performance
systemsofthe
stresses that cause
suspension,
the pole piece to
of the voice coil at hrgh frequencies of each driver
and
acoustic the driver
feedback. IS
highestquality
For maximum
range. The peaksystem gain without
flexibility
offered In two impedance
at 16 ohms, and the 2421A at 8 ohms.
systems or Its high efficiency
permit great dynamic
of the 2421 allows greater
IS
standards
The 2421 is ideally suited for critical playback
is pneumatically
drawn to shape in order to eliminate dimensional
b
wide range
It is built to typical JBL standards
cision. The mathematically
A machrned
quality high frequency
driver which has an exceptronally
in system design,
ratings: the 24218
Model 2421 -Compression Architectural
Specifications
The compressron encased
Driver
driver shall constst of an AlnrcoV
In a cast Iron return circuit. All magnetic
parts shall be machined No ceramic
from cast or extruded
parts shall be used The phasing
assembled
of concentric
horns to minimize
tions, and it shall be further coupled
magnet
assembly
billet stock. plug shall be
phase cancella-
to a tapered
throat,
the mouth of whtch shall be 25 mm (1 in) In diameter back cover shall be cast aluminum prevent ringing resonances.The (0.002 In) aluminum
with reinforcing
diaphragm
alloy pneumatically
The voice coil shall be edgewound
nbs to
shall be 0 05 mm
drawn to shape.
aluminum
less than 44 mm (1% In) In diameter,
The
nbbon of not
operating
In a magnetrc
1
Nominal Efficiency
! / !
Frequency Range
20% f500 Hz to 2500 Hz) 800 Hz to 20 kHz
Distortions
Less than 3%
Recommended Crossover4
800 Hz or higher
Diaphragm
$05 mm (0.002 in) aluminum alloy
-
Voice Coil Diameter
44 mm
j
Voice Coil Material
field of not less than 1.5 tesla (15,000 gauss). An impedance controlling
ring shall be affixed to the pole piece in order to
tncrease efficiency
at high frequencies
and maintain
flat
1%in ound aluminum
response. Performance
specifications
of a typical production
unit shall
; Flux Density ’ BI Factor
be as follows:
1.5 T (15,000 gauss) 5.4 N/E4 (A) 7.7 N/A (B)
Positive voltage to black Measured
sensitivity
with a 1 W input at 1 m drstance on-axis
8 terminal gives diaphragm : motion toward the phasing plug.
from the mouth of a JBL model 2350 90” radial horn, averaged
from 500 Hz to 2500 Hz, shall be at least 110 dB
As an Indication
of electromechanrcal
conversion
the BI factor shall be at least 7 7 15 41 Newtons Frequency
response,
measured
on a terminated
effrcrency,
per ampere. tube, shall
be flat within *5 dB from 800 Hz to 12 kHz. On a JBL Model 2350 horn, response Nominal
impedance
shall be *3 dB from 500 Hz to 15 kHz. shall be 16 (8) ohms and powercapacfty
shall be at least 60 watts normal
speech or musfc program
material.
146 mm (5% in) diameter, 98 mm (3% in) depth
Net Weight
5 kg 5.4 kg
Shipping Weight
12 lb
1. Continuous program power is defined as 3 dB greater than continuous pink noise and is a conservative exoression of the transduce& abilirvto handle normal ’ speech and music program material. Continuous pink noise p&er ratings are testedwith pink noise input having a 6 dB crest factor, with a h@h pass filter set : at the specified lower limitingfrequency.
:
: : !
:
2. Sensitivitymeasured with 1 W input at 1 m distance on axis from the mouth of a JBL 2350 SO0 radial horn, averaged from 800 Hz to 2500 Hz. 3. Third harmonic. IO W inout.
driver shall be JBL Model 2421. Other
drivers will be considered
for equivalency
data from a recognized
verify that the above performance
provided
independenttest specifications
that laboratory
are met.
Frequency response contour of Model 2421 coupled to a 2350 horn Measured response of a typlcal productron unrt, lncludrng all peaks and dips, does not deviate more than 2 dB from the above curve
q
5 Professional
Products
I
11 lb
” 4 A 2421 can be used to 500 Hz, however power capacity will be reduced to 20 W COnttnuOUSprogram tn the regvx between 500 Hz and 600 Hz
The compression submitted
: I
Dimensions
Division
James B. Lansing Sound, Inc., 8500 Balboa Boulevard, P.0. Box 2200, Northridge, California 91329
‘JflL/harman
International
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