Altec Stonehenge II
1970s
The Altec Stonehenge II was the mid-range model in Altec's Stonehenge series. It was a real step up from the Stonehenge I: a 3-way design with a 12" woofer, 5" midrange and a dedicated cone tweeter. It sold for ¥223,700 in Japan (approximately $750 USD in 1976). Altec's own description says it "pursues today's Hi-Fi speakers by gathering technology and craftsmanship based on the tradition of Altec."
Specifications
| Type | 3-way, 3-speaker, bass-reflex floorstanding system |
|---|---|
| Low Frequency Driver | 30 cm (12") cone type woofer |
| Midrange Driver | 13 cm (5") cone type midrange |
| High Frequency Driver | 12 cm (4.7") frame diameter cone tweeter |
| Crossover Frequencies | 500 Hz and 5 kHz |
| Nominal Impedance | 8 Ω |
| Power Handling | 50W continuous program |
| Sensitivity | 89 dB (New JIS) |
| Frequency Response | 35 Hz - 20 kHz |
| Dimensions | 406 mm W × 953 mm H × 362 mm D (16.0" × 37.5" × 14.25") |
| Weight | 27.7 kg (61 lbs) per speaker |
Driver Configuration
The Stonehenge II is a 3-way design with a dedicated driver for each frequency range:
- Woofer: 30 cm (12") cone type woofer - Optimized for bass reproduction in the tuned enclosure
- Midrange: 13 cm (5") cone type midrange - Dedicated driver for critical vocal and instrument frequencies
- Tweeter: 12 cm (4.7") frame diameter cone tweeter - Specialized high-frequency driver for detailed treble
The 3-way design allowed each driver to operate within its optimal frequency range, reducing distortion and improving clarity compared to 2-way designs.
Crossover Design
The crossover network was engineered to blend the drivers together:
- Dual Crossover Points: 500 Hz (woofer to midrange) and 5 kHz (midrange to tweeter)
- Optimized Frequency Division: Each driver handles approximately two octaves for minimal overlap
- Proper Slope Design: Appropriate filter slopes to ensure smooth transitions between drivers
- Component Quality: High-quality capacitors and inductors typical of Altec construction
The crossover point between woofer and midrange is 500 Hz. That puts the mid-bass and lower midrange on the dedicated midrange driver, which helps clarity.
Cabinet Design
The Stonehenge II shares the cabinet design of the rest of the Stonehenge series:
- Monumental Proportions: Tall, slender profile inspired by Stonehenge monoliths
- Premium Materials: Luxurious hand-rubbed Afromosian teak or walnut veneers
- Bass-Reflex Design: Tuned port enclosure for extended low-frequency response to 35 Hz
- Internal Bracing: Robust construction to minimize cabinet resonances
- Domestic Integration: Design that worked well in contemporary living spaces
Despite its sophisticated 3-way design, the Stonehenge II maintained the same compact footprint as the Stonehenge I, making it suitable for average-sized rooms.
Performance Characteristics
The 3-way design offered several performance advantages:
- Improved Clarity: Dedicated midrange driver for cleaner vocals and instruments
- Reduced Distortion: Each driver operating within its optimal range
- Extended Bass: 12" woofer in tuned enclosure reaching to 35 Hz
- Smooth Treble: Dedicated cone tweeter for detailed high-frequency reproduction
- Good Dynamics: 89 dB sensitivity with 50W power handling for dynamic playback
- Wide Dispersion: Conventional cone drivers for consistent room coverage
Historical Context
The Stonehenge II was introduced in the mid-1970s at ¥223,700 and positioned as a premium 3-way speaker in Altec's lineup. Consumer interest in 3-way designs was growing in the mid-1970s, and buyers saw them as more sophisticated and higher-performing than 2-way systems.
The Stonehenge series was Altec's response to a market moving toward conventional driver designs and away from horn-loaded systems. With a 3-way design in the Stonehenge II, Altec could compete with other manufacturers' premium bookshelf and floorstanding speakers and keep its reputation for quality engineering.
The Stonehenge II would have competed with quality 3-way speakers from manufacturers like JBL, Advent and KLH. It offered the Altec name and construction quality at a competitive price point.
Design Philosophy
The Stonehenge II followed several key design principles:
- Technical Sophistication: 3-way design for improved performance over 2-way systems
- Optimized Driver Integration: Careful crossover design for seamless frequency response
- Domestic Refinement: Premium materials and construction for home environments
- Performance Balance: Combining extended bass, clear midrange, and detailed treble
- Brand Identity: Maintaining Altec quality in a conventional speaker design
Amplifier Compatibility
With 89 dB sensitivity and 8Ω impedance, the Stonehenge II worked well with:
- Medium-powered amplifiers (30-100W) for optimal performance
- Quality vintage receivers from the 1970s
- Modern integrated amplifiers with 50W+ output
- Tube amplifiers with sufficient power (20W+)
The moderate efficiency meant it needed reasonable amplifier power to reach satisfying volume levels. It was still more efficient than many modern speakers.
Legacy and Collectibility
The Altec Stonehenge II is a rare and interesting collectible today, representing Altec's approach to conventional 3-way speaker design during the 1970s. Complete, original examples can command prices of $800-$1,500 per pair depending on condition and driver functionality.
Factors contributing to the Stonehenge II's collectibility:
- Technical Interest: 3-way design different from most Altec horn systems
- Design Distinctiveness: Stonehenge series aesthetics
- Brand Appeal: Altec name and construction quality
- Rarity: Less common than mainline Altec models
- Performance: Capable 3-way design that still sounds good today
Restoration considerations include:
- Recapping the crossover network with dual crossover points
- Refoaming the 12" woofer if needed (likely foam surround)
- Checking the 5" midrange driver for proper operation
- Testing the cone tweeter for high-frequency response
- Cabinet refinishing to restore teak or walnut veneer
eBay Listings
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.
Images
The following sources may have images of this equipment. Always verify license terms and provide proper attribution when required.
Source 1: HiFi Wiki
- Link: HiFi Wiki
- License: Varies - check individual image
- Attribution Required: Yes
- Commercial Use: Unknown - verify on site
- Notes: User-contributed content. Attribution recommended.
Source 2: HiFi Engine
- Link: HiFi Engine
- License: User-contributed manuals
- Attribution Required: Yes
- Commercial Use: Reference only
- Notes: Great for specs/manuals. Request permission for images.
Source 3: Audio Database
- Link: Audio Database
- License: User-contributed
- Attribution Required: Yes
- Commercial Use: Unknown
- Notes: Verify license before use.
Source 4: Radio Museum
- Link: Radio Museum
- License: User-contributed
- Attribution Required: Yes
- Commercial Use: Unknown
- Notes: Attribution required for user photos.
Attribution Notice: This page links to external image sources. When using images from these sources, ensure you comply with their license terms. CC0 images require no attribution. CC BY and CC BY-SA images require attribution.
Documentation
- Altec Stonehenge II specification sheets
- Stonehenge series marketing materials
- Altec home audio catalogs (1970s)
- Crossover network schematics (500 Hz / 5 kHz)
Related Models
- Altec 1803B
- Altec 23746 (1975)
- Altec 26421 (1975)
- Altec 288-16G
- Altec 288-8H/16H
- Braun AUDIO-1 (1965)
- Braun AUDIO-250 (1965)
- Magnavox Component Systems (1972)
- Acoustic Research AR (1967-1976)
- Acoustic Research 11