JBL S50 (1983–1985)
A 29-pound bookshelf monitor that asks for 10 watts and gives you 40kHz of extension.
Overview
The JBL S50 is a three-way, bass reflex bookshelf speaker that JBL built from 1983 to 1985. It weighs 29 pounds and measures 17.75 inches high by 13.5 inches wide by 9 inches deep. That's a lot of box, and it needs a sturdy shelf. The finish is walnut vinyl. This was never meant to be a museum piece, it was meant to get played.
The S50 is ambitious. It's rated at 89 dB sensitivity, with a frequency response of 45Hz to 40kHz. That covers the full audible spectrum plus some extra headroom. The 40kHz top end wasn't just marketing - it gave the S50 room to breathe with early digital sources that pushed ultrasonic noise into the audible band through intermodulation distortion. A period survey of monitor loudspeakers noted that models with extended high-frequency response were better equipped to handle the demands of studio monitoring (Studio Sound, September 1980, p.42). The survey also listed a monitor with a maximum power input of 30W and a frequency response of 30Hz to 20kHz, which shows the range of specifications in studio monitors of that era (Studio Sound, September 1980, p.42). With that extended response, the tweeter wasn't working at its mechanical limits on standard 20kHz content.
Power handling is rated at 10 to 100 watts, a practical range for the receivers and integrated amps of the era. The 8-ohm nominal impedance suits virtually any amplifier from the period. At $380 per pair in 1983, the S50 was a substantial investment for a bookshelf speaker.
Key Features
10-Inch Woofer in a Bass Reflex Cabinet
The foundation is a 10-inch woofer in a bass reflex enclosure. The ported design is what lets a bookshelf speaker this size reach down to 45Hz. A comparatively large woofer and a tuned port mean the S50 can move real air. These aren't polite little boxes that hint at bass. The 45Hz low end is respectable for a bookshelf design from this period, and the bass reflex loading gives it efficiency that a sealed box of the same volume couldn't match.
5-Inch Midrange and 1-Inch Tweeter
Above the woofer sit a 5-inch midrange driver and a 1-inch tweeter. The crossover is set at 3000Hz, a conventional point that keeps the midrange in the vocal and instrument fundamental range and leaves the harmonics and air to the tweeter. No single driver is asked to do too much. The woofer isn't straining to produce midrange, and the tweeter isn't pushed down into frequencies where small domes get harsh.
Walnut Vinyl Finish
The S50 came in walnut vinyl, a practical choice for a speaker aimed at real-world living rooms. It resists the scratches and scuffs that would show on a lacquered cabinet, and it keeps costs down. This wasn't furniture-grade stuff, but the vinyl was durable and period-appropriate.
Collectibility & Value
Current listings show a pair going for around $225 on Reverb, with more pairs on eBay, Canuck Audio Mart, and US Audio Mart. That's a modest price for a three-way JBL from the early 1980s, and it reflects the S50's status as a well-regarded but not legendary model.
Owner comments in the wild are brief but generally positive. One Canadian listing describes them as "very nice sounding," and a US seller notes "good clean sound." They aren't gushing reviews, but they're consistent.
One caution from the forums: an Audiokarma poster claimed the S38 and S50 are "some of the worst JBLs in terms of reliability." That attribution is shaky. The same poster appears confused about JBL model numbering elsewhere in the thread, and no other source corroborates a specific reliability problem with the S50. There are also no capacitor replacement guides or foam rot warnings circulating for the S50 specifically, which suggests the drivers and crossovers have held up reasonably well compared to some of JBL's later designs that developed known failure modes. As with any speaker from this era, check the surrounds on the woofer and midrange before buying.
At $225 to $380, the S50 is a way to get a real three-way JBL without paying collector premiums. They're not investment pieces.
eBay Listings
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