JBL 2135 (Years Unknown)

Documentation on the JBL 2135 is thin, and what exists comes mostly from owner forums rather than official JBL literature. What the record shows: this is a 12-inch driver with an alnico magnet and a foam surround, built for JBL's professional studio monitor line (Audio, July 1982, p.33). It's a "fairly rare driver," as one forum poster put it, and it commands attention when it appears on the used market.

The 2135's claim to fame is its dual voice coil configuration — two 8-ohm coils that wire in series for a 16-ohm nominal impedance. The cone carries JBL's Aquaplas coating, and the whole assembly sits on a substantial magnet structure. Owners describe it as a mid-bass driver, though some sources call it a woofer, and it was reportedly used in the 4340-series studio monitors — with conflicting claims about whether it appeared in the 4341 or the 4343. JBL's standard history puts the 2121 in the 4341 and the 2122 in the 4343, so the 2135's exact role in that family is unclear from the available sources.

What owners agree on: the 2135 sounds very good as a mid-bass driver when crossed around 1kHz, and it's a great woofer for the 4341s. The foam surrounds are the weak point — they rot out over time, and replacement foam kits run about $80 per set. One owner noted having theirs refoamed without issue. A pair recently listed on a vintage audio Facebook group at $1,000, which gives some sense of its collectibility.

Notably, the 2135 doesn't appear in the period directories that Audio published in the early 1980s (July 1982 and July 1983 issues don't list JBL among manufacturers), and no original price or production dates have surfaced. All specifications here come from enthusiast postings, not JBL datasheets, so treat them as field reports rather than factory specs.

Known specifications (from owner sources):