JBL S105 Aquarius I
1971 - 1973
Introduction
The JBL S105 Aquarius I is a three-way non-directional speaker system, the first model in the Aquarius series. It used front-firing slot-loaded drivers and elliptical diffraction panels to give a wide soundfield that stayed consistent wherever the listener sat. It was a "noble experiment" in audio engineering.
Overview & Specifications
| Specification | Details |
| Type | 3-way, 3-driver bass reflex non-directional bookshelf |
| Woofer | 10" (25cm) LE10 cone woofer |
| Midrange | 5" (12.7cm) LE5 cone midrange |
| Tweeter | 2" (5cm) LE20-1 cone tweeter |
| Crossover Frequencies | 300 Hz, 1,000 Hz, 3,500 Hz |
| Nominal Impedance | 8 Ω |
| Power Handling | 50W continuous program |
| Sensitivity | 89 dB/W/m |
| Frequency Response | 45 Hz - 20 kHz |
| Dimensions (W×H×D) | 508 × 508 × 343 mm (20" × 20" × 13.5") |
| Weight | 21.25 kg (47 lbs) |
| Finish | Walnut or satin white veneer |
Driver Configuration
The driver complement was borrowed from JBL's successful 4310 studio monitor and the later L100 home speaker. The LE10 woofer was a 10-inch design known for its bass response and control. In the Aquarius I, it fired forward into an elliptical diffraction panel that created slot loading and spread the bass widely through the room.
The LE5 midrange was JBL's acclaimed 5-inch hard-cone driver, known for transparent, natural vocals. Like the woofer, it worked through its own elliptical diffraction panel, which gave a dispersed midrange and added to the speaker's non-directional character.
The LE20-1 tweeter handled the highs. It was a direct-radiating element, kept that way to hold on to some image localization. It's a 2-inch cone tweeter with smooth, extended highs and the usual JBL clarity.
The three-way network has crossover points at 300 Hz, 1,000 Hz, and 3,500 Hz. It was designed for the Aquarius I's non-directional approach, and it sets how the slot-loaded drivers interact with the direct-radiating tweeter.
Design & History
The Aquarius series came out of JBL's wish to build speakers with few limits on room placement and a stereo soundfield largely independent of where the listener sat. JBL had already pioneered the idea in its Ranger designs (Paragon, Metregon, Minigon), but those needed large, curved dispersion panels and unusual enclosure geometries. The Aquarius series went after similar results with slot loading and diffraction panels.
Ed May, JBL's head of Product Development, directed the project. The Aquarius I was based on the slot loading principle May had pioneered with Jack Frazier in the 1950s. The front-mounted drivers fired into elliptical diffraction panels that made a dense comb filter, keeping power response reasonably flat at almost any listening spot.
The Aquarius I was the least prone to production variations in the series and was arguably the best-sounding model. The design evolved empirically. The elliptical shapes of the diffraction panels came from extensive testing, not theoretical calculation.
The Aquarius I came in two color variations: traditional walnut veneer and contemporary satin white, in line with the design trends of the early 1970s. An optional mounting base was sold separately for floor placement.
Sound Character
The Aquarius I's sound is best described as "spacious, immersive, and remarkably consistent throughout the listening area." The slot-loaded design makes a wide, deep soundstage that seems to come from the entire front wall instead of discrete speaker locations. That non-directional character suits social listening, with several listeners spread around the room.
Bass is surprisingly full and extended for a speaker this size, and the slot loading provides both dispersion and reinforcement. The low end feels effortless for a woofer of only 10 inches.
The midrange is transparent and natural. Vocals and instruments appear in the soundfield instead of being anchored to the cabinets. The LE5 midrange gives its usual clarity and detail, with a more diffuse presentation than conventional designs.
The highs keep good detail and air while adding to the dispersed soundfield. The direct-radiating tweeter gives enough localization to maintain stereo imaging while staying within the non-directional concept.
Placed properly, on bookshelves, stands, or the optional floor base, the Aquarius I is less about pinpoint imaging and more about immersive musical envelopment. It does well with acoustic music, jazz, and classical recordings, where a natural, room-filling presentation is wanted.
Collector's Notes
The Aquarius I is among the rarest and most collectible JBL speakers.
The LE10 woofers generally need foam surround replacement. The LE5 midranges are durable but can suffer from hardened suspensions. The LE20-1 tweeters are quite reliable. The elliptical diffraction panels are fragile and often damaged, and intact originals are extremely rare. Cabinets in satin white are particularly scarce and desirable.
The Aquarius I is one of JBL's most unusual and short-lived designs, and it commands premium prices. Unrestored pairs typically sell for $1,500-2,500. Professionally restored examples with intact diffraction panels can reach $3,000-4,000. Complete sets with original boxes, documentation, and optional bases are museum pieces.
Restoring Aquarius I speakers takes particular care with the diffraction panels. Never remove or alter them. The slot loading depends critically on their precise geometry. Crossover restoration should use high-quality components to keep the original voicing. Cabinet restoration should preserve the original finish whenever possible.
The Aquarius I pairs well with moderate-powered amplifiers (30-100 watts) that can drive the 8-ohm load. They're particularly engaging with tube amplification, which suits their warm, spacious character. They work well with both analog and digital sources, and their non-directional nature makes them less critical of precise setup than conventional speakers.
The JBL S105 Aquarius I showed JBL's willingness to challenge audio conventions and look for new solutions to listening room problems. It was a "noble experiment" that pushed what was possible in home audio.
Documentation
Factory Technical Documents
- S105 Aquarius I Technical Manual (PDF) - Factory technical documentation
- Audio Heritage - S105 Technical Manual - Technical documentation
Service & Maintenance
- Servlib - S105 Aquarius I Service Manual - Service manual download
Historical Articles
- Audio Heritage - Aquarius Series Profile - Historical overview of Aquarius line
Product Catalogs
- Audio Database - Aquarius I Specifications - Detailed specifications
External Resources
- Lansing Heritage - JBL historical archives
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