JBL 4425MKII (c. 1998)
The 4425MKII is a refinement of JBL's 4425 studio monitor, which first appeared in 1985. The MKII kept the original's design concept and added technology developed for the Project K2 and 4344 MKII flagships. It's a 2-way, bass-reflex bookshelf design - though "bookshelf" is generous, since each cabinet weighs 25.8 kg and stands 635 mm tall. The price reference we have is ¥195,000 per unit, from around 1998.
The drivers are a 30 cm 1200H woofer and a 175nd compression driver on a bi-radial horn. The woofer cone is a fiber composite of glass fiber mixed with pulp paper, treated with JBL's Aqua Plus coating. It has a 3-inch edgewise wound voice coil and an SFG magnetic circuit to reduce second harmonic distortion. The high-frequency driver has a pure titanium diaphragm with a diamond-structure edge, a neodymium magnet, and Ferrofluid cooling in the voice coil gap. The horn is a new-generation bi-radial design with 100° constant directivity in both horizontal and vertical planes, molded from a special resin.
The crossover is where the K2 influence shows most. It uses the biased network technology from the K2 series, including a charge-coupled linear definition method that applies DC bias to the high-frequency network. That lets the capacitors operate in class A and eliminates zero-cross distortion. The HF level is continuously adjustable, and the gold-plated inputs allow bi-wiring or bi-amplification. The enclosure has the same baffle and floor dimensions as the original 4425, so it drops in as a replacement. It's 19 mm particle board with internal bracing, an MDF baffle with a smoothly curved bass reflex port opening, and a walnut veneer finish on five sides.
Specs as documented: frequency response of 35 Hz to 20 kHz (-6 dB), 91 dB/W/m sensitivity, 8 ohms impedance, 200W continuous program / 800W peak input, and an 1100 Hz crossover (12 dB/oct). A matching JS-50 stand was available separately at ¥25,000. JBL positioned it for both near-field and mid-field monitoring.
The record on this model is thin. No formal period reviews have surfaced in the available documentation, and production years beyond the "around 1998" price reference aren't confirmed. What exists is enthusiast commentary. It's described as delivering "crystal-clear and powerful audio reproduction of professional quality," and it's noted as being manufactured in California. One Chinese-language source observes that the MKII's horn is shallower than the original 4425's, the tweeter adjustment went from two knobs to one, and the port openings are connected by a shallow groove. The same source says the horn port on surviving examples often shows visible oxidation, a common sign of age on these.
The same source notes the 4425MKII has held its value well. The second-hand price in China was around ¥22,000 RMB, roughly double the original Japanese list price converted. That's anecdotal.
- Type: 2-way, 2-speaker, bass-reflex bookshelf
- Low band: 30 cm cone (1200H)
- High band: 175nd compression driver + bi-radial horn
- Frequency response: 35 Hz – 20 kHz (-6 dB)
- Sensitivity: 91 dB/W/m
- Impedance: 8 Ω
- Power handling: 200W continuous program / 800W peak
- Crossover: 1100 Hz (12 dB/oct)
- Dimensions: 409W x 635H x 313/360D mm (incl. horn)
- Weight: 25.8 kg
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