JBL 4428

Commentary

A middle-size studio monitor speaker system that inherits the technology of high-end machines.

The low range is equipped with 1200FE-8 which is 30 cm cone type woofer.
This unit is a 1200 fe impedance of 8 Ω specification used for Project K2S 5800.
The diaphragm uses Kevlar composite cone which increases the strength of the diaphragm by mixing Kevlar fiber with pulp material, and in addition, JBL's unique Aqua Plus coating is applied.
In addition, we have adopted a double damper for increasing linearity, an aluminum die-cast frame for the frame, a new symmetrical field geometry (SFG) magnetic circuit and an aluminum ribbon edgewise wound voice coil for low-distortion, high-reality low-frequency reproduction that does not move even in high-power drives.

The high range is equipped with a horn type mid-range which combines a 5.0 cm driver unit 175Nd-2 and an HF/UHF combination horn.
Pure titanium diaphragm with Aqua Plus coating is used for the diaphragm, and rapid flare exit method with low distortion is used for the phase plug.
The magnetic circuit uses a lightweight aluminum ribbon voice coil and neodymium magnet. By sealing magnetic fluid in the voice coil gap, the heat generated by the voice coil is cooled and power handling is improved.

A horn type tweeter combining a 015M 1.9 cm ring type tweeter and an HF/UHF combination horn is mounted in the ultra-high band.
A polyimide diaphragm is used for the diaphragm, and by integrating the diaphragm and bobbin, the vibration system mass is reduced and transmission loss is suppressed.
A bullet-shaped center equalizer is mounted on the front of the diaphragm to limit the attenuation of high-frequency energy due to phase interference.

A combination horn made by SonoGlass is used for the high-pass and ultra-high-pass horns. By using an integrated combination horn, the performance of each driver is brought out and the acoustic connection is improved. The directivity angle is 60 ° horizontal x 40 ° vertical for the ultra-high-pass and 90 ° horizontal x 40 ° vertical for the high-pass.
This horn has an integrated structure with the upper baffle.

A separate network is used for the network section, and the network circuits for the low band and for the high band or higher are separated and independent.
High-quality parts such as air-core coils and polypropylene film capacitors are used in the device.

A continuously variable attenuator is installed in the high and ultra high frequencies.

The enclosure uses a bass reflex system.
The unit layout adopts an inline method in which units are arranged on a vertical line, and the sound image is positioned more clearly.
High-rigidity MDF material of 25 mm thickness is used for the plate material. In addition, round processing is applied to the symmetrical twin bass reflex port to suppress the breathing of the port.

The input terminal uses a gold-plated speaker terminal for bi-wiring connection.

There was a special speaker stand as an option sold separately.

Model Rating

Method	3-Way, 3-Speaker, Bass reflex system, Bookshelf Type
Units Used	For Low Band : 30 cm Cone Type (1200FE-8) For High Range : 5.0 cm Screwdriver (175Nd-2) + Horn For Super High Band : 1.9 cm Ring Type (015M) + Horn
Frequency characteristic	40 Hz to 40 kHz -6dB
Impedance	8 Ω
Output sound pressure level	91dB/2.83V/m
Allowable input	200W(RMS)
Crossover frequency	900 Hz, 7 kHz
External dimensions	Width 400x Height 635x Depth 338 mm
Weight	32.5kg
Sold Separately	Speaker Stand JS-350A (1 unit, ¥ 35,000)