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| JBL 4345 |
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| 850,000yen(one-set, around the 1981 time) |
The large-sized speaker system of the professional
series which adopted the newly developed 46cm Woofer.
46cm cone type
Woofer 2245H developed by uniting examples of traditional craftsmanship and a
state-of-the-art technology is carried in low-pass.
It improves property
sides, such as efficiency, a linearity, a low distortion, and it not only says
that cone paper only expanded this Woofer compared with the conventional 38cm
cone type Woofer, but enables the outstanding low-pass play.
The material
selected carefully is used for a cone part, and in order to make a mass and
rigidity the optimal, the dumping agent (Langsa positive) original with JBL is
applied to a back side.
Moreover, the SFG structure of JBL original is adopted as a magnetic circuit,
the magnetic field in a voice coil gap is made symmetrical, and the second
higher-harmonic distortion is conjointly reduced with the flux stabilizing
ring wound around pole piece.
Furthermore, the
large diameter of 100mm of a piston action area and a thing 25mm in length are
adopted, the amount of linear peek displacement amounts to 20mm, and the voice
coil lessens the comression of the output at the time of high power with the
enhancement of heat sink capacity.
2122H of a 25cm cone type Woofer is
carried in inside low-pass.
The new cone paper which decreased the distortion besides a cross over
frequency is adopted, and the copper ribbon voice coil of the diameter
of 75mm, the SFG magnetic circuit, etc. are carried.
The closed mold back
cavity was prepared in these 2122H, and the interference from other units is
prevented.
The driver 2420 and the horn lens 2307+2308 are carried in
the mid-high range.
Moreover, 2405 was carried in the high region which
reproduces 10kHz or more, new technology was carried in the ring diaphragm of
the ultra-thin manipulation, and top endless bitter orange juice is improved.
The network part is developed based on the new high separation network
design of JBL, makes relation of sound smooth by adding a small capacity
capacitor to the mass capacitor selected carefully, and is raising the
transparent feeling.
Moreover, a two-channel multi-amplifier drive (channel
dividers 5234 using) is carried out at 290Hz, and also the drive by a built-in
network is possible.
The enclosure is carrying out the design which uses
the hard particle board of 21mm thickness, and also prevents an unnecessary
oscillation of a stationary wave etc. by considering internal reinforcing
materials as an asymmetrical placement.
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.JPG)
| Scheme |
4 ways, 4 loudspeaker bass-reflex scheme,
and a floor type |
| Unit |
For low-pass: 46cm cone type (2245H)
For
inside low-pass: 25cm cone type (2122H)
For mid-high ranges: Horn type
(2420+2307+2308)
For high regions: Ring type (2405) |
| Frequency characteristic |
32Hz-20kHz±3dB |
| Directivity (horizontal x vertical)
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60 degrees x 30 degrees (-3dB, 16kHz)
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| Output sound pressure level |
95dB/W/m |
| Impedance |
8ohms |
| Allowable input |
120W (at the time of a network)
200W
(multi-amplifier Lo)
100W (multi-amplifier Hi) |
| Cross over frequency |
320Hz, 1.3kHz, 10kHz (at the time of a
network)
290Hz, 18dB / oct (at the time of multi-amplifier)
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| Enclosure dimension |
253L (Woofer)
14L (mid Woofer)
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| Dimensions |
Width 765x height 1096x depth of 470mm
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| Weight |
112kg (at the time of an original packaging)
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