JBL MI-630 (circa 1987)

The JBL MI-630 is a portable PA/sound reinforcement speaker from the mid-1980s. It belongs to JBL's MI series, which was developed specifically for SR (sound reinforcement) use. It's a 2-way, 2-driver bass reflex system in a floor-type enclosure, and it looks to have been aimed squarely at the working musician. An April 1987 advertisement in Musician magazine pitched it as giving "new voice to your vocals," delivering "unparalleled power, range, and clarity in a rugged, compact, portable package."

The low end is handled by a 30 cm (12") cone woofer, the MI-12. JBL touted it as high-efficiency, with an edgewound voice coil and SFG magnetic structure. High frequencies come from a horn-loaded compression driver, the 2415H, paired with a 2371 horn. The system is rated at 300W continuous program power, with a frequency response of 60 Hz to 15 kHz, an output of 100 dB/W/m, and a crossover at 2 kHz. Dispersion is specified at 90° horizontal by 40° vertical. Impedance is 8 ohms. Each cabinet weighs 20 kg (about 44 lbs) and measures 455 x 530 x 295 mm.

Documentation on the MI-630 is thin. The price notation of ¥145,000 per unit (circa 1987) comes from a Japanese spec database, and no production years, market context, or owner reviews have surfaced. The record is essentially one advertisement and one spec sheet. What's clear is that this was a professional-oriented, no-frills box — the sort of speaker a working band would haul to a gig, not a home hi-fi statement. That it was built around a 12" woofer with an edgewound voice coil and SFG magnet places it firmly in JBL's pro lineage of the era.

Known Specs

• Type: 2-way, 2-driver, bass reflex, floor-standing
• Low-frequency driver: 30 cm cone (MI-12), edgewound voice coil, SFG magnet
• High-frequency driver: 2415H compression driver with 2371 horn
• Frequency response: 60 Hz – 15 kHz
• Impedance: 8 ohms
• Output: 100 dB/W/m
• Power handling: 300W continuous program
• Dispersion: 90° x 40°
• Crossover: 2 kHz
• Dimensions: 455 x 530 x 295 mm (W x H x D)
• Weight: 20.0 kg

eBay Listings

Replacement Diaphragm for JBL MI-261, MI-291, MI-630, MI-631

$32.99

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