JBL S109 Aquarius IV (1970s)

The JBL S109 Aquarius IV is a 2-way loudspeaker from JBL's Aquarius line. JBL described the line as "non-directional" - the woofer fires upward into a radial horn, which diffuses acoustic energy across 360 degrees and makes a wide sound field. The Aquarius series was groundbreaking in both technology and style, though with one exception its existence would prove fleeting. Development of the earlier Aquarius models was virtually complete when Ed May left JBL in 1970. Refinement of the partially complete Aquarius 4 fell to George Augspurger, then JBL's Technical Director.

The S109 pairs an upward-firing 8-inch woofer with a 1.5-inch tweeter. The woofer is the LE8T, specifically the LE8T-2, an 8Ω variant said to be unique to the Aquarius. The tweeter is the LE20-1. A Craigslist listing documents the drivers with serial numbers - woofers 25110/25219, tweeters 184263/184302 - and lists the crossover points at 800Hz and 3000Hz, max input of 35W, and 8-ohm impedance. Cabinets are walnut veneer, measuring 10" W × 40" H × 11" D per unit. One forum owner notes a single 8" fullrange driver fired into the horn arrangement, which fits the upward-firing design.

Documentation on the Aquarius IV is thin. Production dates are given loosely as "early 1970s," with one forum post specifically citing 1974 and a UK price of £50. The line included Aquarius models 1, 2, 2A, 3, and 4, with the Aquarius 1 modeled on the successful 4310 monitor and subsequent L100. An audioheritage.org photo shows the full line circa 1970. The S109 is considered rare today. A Reverb listing asking $899 for a pair noted the "rare LE8T-2 8Ω" driver, and a San Francisco Craigslist ad asked $800. One seller described their pair as "beautiful" in both look and sound, though condition varies. One listed pair had a single woofer recently reconed.

Known specs, as documented: