JBL MI-632
The JBL MI-632 is a 2-way, 2-speaker front horn system from JBL's MI series. The line was developed around the concept of "JBL sound for more players" and aimed at working musicians and small-venue sound reinforcement. A 38 cm cone woofer (the MI-15A) handles the low band. A horn-type high-frequency unit with the 2415H driver and 2371 horn handles the highs. The system is rated at 104 dB/W/m, with a stated playback band of 45 Hz to 15 kHz, an 8 ohm impedance, and 300W continuous program input. Crossover is at 1.5 kHz, with 90° x 40° dispersion. Each cabinet measures 630 x 830 x 440 mm and weighs 45.4 kg.
The MI-15A woofer has a low-distortion SFG magnetic circuit and a four-layer voice coil. The high-frequency driver uses a titanium diaphragm with a diamond suspension. The enclosure is a front horn design, a configuration JBL used in this era to get high efficiency out of modest amplifier power, which suited the MI series' SR-focused intent. The MI-632 was priced at ¥225,000 per unit around 1984. A revised version, the MI-632A, appeared around 1987 at ¥195,000 per unit. It was described as a "newly re-designed system" with the newer MI-15A woofer and a copper ribbon voice coil.
Period listings also show the MI-632A as a bass reflex/horn hybrid on the woofer. That suggests the "front horn" designation covers a partially horn-loaded, partially ported enclosure. Be careful with listings: some "MI-632" cabinets are replicas built with genuine JBL drivers, not original JBL enclosures, so verify before buying. A forum user on audioheritage.org reported that what they thought were MI-632A cabinets turned out to be G-732s, and they found them underpowered for their needs.
Documentation on the MI-632 is thin. Most of what is recorded comes from Japanese audio databases and classified listings rather than period reviews. A German-language source (robertmelchers.nl) describes the MI-632A as a complete loudspeaker combining the woofer's horn/bass reflex loading with a driver/horn for the highs. Guitar Center has carried used MI-632A units described as suitable for small venues or practice setups. No official JBL spec sheets or owner's manuals have surfaced in the available record, and no production years beyond the approximate price dates above are confirmed.
Known specifications:
- Type: 2-way, 2-speaker, front horn system, floor type
- Low band: 38 cm cone (MI-15A)
- High frequency: horn type (2415H driver + 2371 horn)
- Frequency range: 45 Hz – 15 kHz
- Impedance: 8 Ω
- Output: 104 dB/W/m
- Power handling: 300W continuous program
- Dispersion: 90° x 40°
- Crossover: 1.5 kHz
- Dimensions: 630 W x 830 H x 440 D mm
- Weight: 45.4 kg
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