JBL 2120 (1971–1976)

Name: JBL 2120
Brand: JBL

The JBL 2120 is a compact two-way bookshelf monitor from the early 1970s, produced from roughly 1971 to 1976. It pairs an 8-inch woofer with a 1-inch tweeter through a 2600 Hz crossover. Both surviving sources agree on the basics: 8 ohm impedance, 92 dB sensitivity, and a modest 15-30 watt power range. It's a small speaker, around 13.5 by 17.5 inches front-on and about 10 inches deep, made for a shelf and not the floor.

The record on this model is thin. What exists comes from two enthusiast databases, hifi-wiki and The Classic Speaker Pages, and they disagree slightly on the numbers. One lists frequency response as 62 Hz to 21 kHz. The other says 67 Hz to 21 kHz. Cabinet dimensions differ too, though the sources appear to list the measurements in different orders (width × height × depth versus width × depth × height), which may explain part of it. Weight is given as 8.16 kg, or about 18 lbs.

Past those basics, almost nothing is documented. No original price, no cabinet construction details, no crossover schematic, and no period reviews have surfaced. Going by the specs, it looks like a sensible entry-level or secondary-room monitor from JBL's early-70s consumer line, the kind that would have driven a modest receiver comfortably. That's inference, not fact.

Known specifications: