Kenwood LS-M7 (1989)

The Kenwood LS-M7 is a three-way bookshelf speaker from the late 1980s. It sold for ¥65,000 per unit around 1989. It's a big "bookshelf" design at 24 kg and 578 mm tall, and the spec sheet reads like Kenwood was trying to cram flagship thinking into a smaller cabinet.

The low end is a 27 cm cone woofer, chosen, per period documentation, with cabinet size, low-frequency extension, and efficiency in mind. It has a Cloth-dyneema diaphragm - a composite of Dyneema and carbon fibers arranged in longitudinal and transverse layers - plus a long voice coil and an aluminum die-cast frame. The midrange is a 9 cm semi-dome, and the tweeter is a 2.5 cm dome. The midrange gets the most elaborate treatment: a "plasma diamond" diaphragm (diamond formed onto titanium via plasma energy), a semi-dome structure with reduced weight, and an aluminum die-cast spherical wave horn baffle to reduce diffraction.

The cabinet is built with care. The baffle is 40 mm thick, made of two 20 mm plates bonded together. The side, top, and bottom panels are 18 mm and the back is 20 mm. Per Kenwood's own description, the idea was to vary panel thickness to change vibration modes for more natural expression. The enclosure is compact up front but deep, with a rear-offset bass reflex port. The low, mid, and high networks are each dedicated and physically separated, to minimize interference from vibration, magnetic induction, and component coupling.

Rated specs: 28 Hz to 47 kHz playback, 200W (EIAJ) max input, 6Ω impedance, 91 dB/W/m sensitivity, crossovers at 300 Hz and 6.5 kHz. Kenwood offered a matching SG-M7 stand (¥35,000 per pair, 9 kg each, with pinpoint bases).

Not much is on record about how the LS-M7 was received. One repair shop documented a unit that arrived with a botched edge (surround) repair - a soft cloth glued on with double-sided tape and wood glue, causing coil rub and a "gari gari" grinding noise. The shop replaced it with an original edge and noted that such sloppy repairs are common on auction units. Check the edges if you're buying one today.

Audio Database (accessed 2026) corroborates the core specifications and design details above, including the ¥65,000 price and the SG-M7 stand.