Altec Stonehenge III

1975 - 1977

The Altec Stonehenge III is the flagship of Altec's Stonehenge series. Altec billed it as "a classic of contemporary technology" inspired by "an ancient mystery." The speakers paired advanced audio engineering with a dramatic, monolithic cabinet. The Stonehenge III used the 604-8G coaxial driver in a massive, handcrafted enclosure.

Specifications

Type	2-way coaxial (duplex) loudspeaker system
Driver	604-8G 15" coaxial driver
Configuration	15" woofer with integrated high-frequency compression driver and horn
Crossover Frequency	1,600 Hz
Nominal Impedance	8 Ω
Power Handling	50W continuous, 100W program
Sensitivity	98-100 dB/W/m
Frequency Response	35 Hz - 18 kHz
Cabinet Type	Massive bass-reflex enclosure
Cabinet Material	Luxurious hand-rubbed Afromosian Teak (African oak)
Cabinet Dimensions	Approximately 42" H x 28" W x 20" D
Weight	Approximately 150-180 lbs per speaker

The Stonehenge Series

Altec produced three models in the Stonehenge series:

Model	Driver	Characteristics
Stonehenge I	Unknown, likely 12" or 15" driver	Entry model, still substantial
Stonehenge II	Unknown, improved driver	Mid-range model
Stonehenge III	604-8G coaxial	Flagship with best components

All Stonehenge models shared the monolithic cabinet design and were marketed as combining ancient mystery with contemporary technology.

The 604-8G Duplex Driver

The Stonehenge III used Altec's 604-8G coaxial driver:

Woofer: 15" cast-frame woofer with Alnico V magnet
High-Frequency Driver: Integrated compression driver with 1.75" aluminum diaphragm
Horn: Small format horn integrated into the driver's center
Crossover: Internal crossover network at 1,600 Hz
Coaxial Design: Single-point source for perfect time alignment

The 604-8G was widely regarded as one of the best coaxial drivers ever made. It was used in professional monitoring applications worldwide.

Cabinet Design and Construction

The Stonehenge III cabinet was a serious piece of woodworking:

Material: Afromosian Teak (African oak), known for its beauty and durability
Finish: Hand-rubbed oil finish that highlighted the wood's natural grain
Construction: Massive, monolithic design inspired by ancient stone structures
Internal Volume: Very large enclosure optimized for the 604 driver
Bass Reflex: Tuned port for extended low-frequency response
Internal Bracing: Extensive bracing for cabinet rigidity
Acoustic Treatment: Proper damping for clean sound

The cabinet was designed to look striking and to work well acoustically. It had the mass and rigidity to support the 604 driver's performance.

Marketing and Mystique

Altec's marketing for the Stonehenge series played on 1970s fascination with ancient mysteries:

"Ancient Mystery": Referenced the actual Stonehenge monument's unknown origins
"Contemporary Technology": Highlighted the advanced audio engineering
Monolithic Design: Cabinet shape evoked ancient stone structures
Luxury Positioning: Targeted affluent audiophiles seeking statement pieces
Mystical Appeal: Tapped into 1970s interest in occult and mysterious subjects

This approach was unusual for Altec, which typically stuck to technical specifications and professional heritage.

Performance Characteristics

Owners and reviewers describe the Stonehenge III as:

Exceptionally Coherent: Coaxial design provides perfect driver integration
Powerful and Dynamic: Capable of very high output levels
Deep Bass Extension: Large cabinet provides solid low-frequency response
Detailed and Transparent: 604 driver renowned for its clarity
Excellent Imaging: Single-point source creates precise soundstage
Effortless Presentation: High sensitivity allows easy driveability

One owner noted that Stonehenge speakers "threw the performers out of the speakers and into the middle of the room," with impressive soundstage depth and width.

Rarity and Collectibility

The Stonehenge III is exceptionally rare due to:

Limited Production: Small numbers produced due to high cost
Short Production Run: Only 2-3 years of production
High Original Price: Would have been very expensive when new
Survival Rate: Few examples have survived in good condition
Specialized Market: Appealed to a narrow segment of buyers

That rarity makes the Stonehenge III one of the most sought-after and valuable vintage Altec speakers.

Comparison with Other High-End Speakers

Speaker	Era	Driver	Price Range (Current)
Stonehenge III	1975-1977	604-8G coaxial	$3,500-$5,000+
Altec Model 19	1977-1980s	416 + 802/811B	$3,000-$4,500
JBL L300	1970s	LE15 + LE85 + LE25	$4,000-$6,000
Klipschorn	1970s	15" + horn tweeter	$3,000-$5,000

Restoration Challenges

Restoring a Stonehenge III presents unique challenges:

Cabinet Restoration: Afromosian Teak requires specialized refinishing
Driver Preservation: 604-8G drivers must be preserved or properly restored
Parts Availability: Some components may be difficult to source
Expert Knowledge: Few technicians have experience with these rare speakers
Documentation: Original documentation is scarce

Given their value and rarity, Stonehenge III speakers should be restored by experts familiar with vintage Altec products.

Historical Context

The Stonehenge III was introduced in the mid-1970s, a period of technical advancement and cultural fascination with mystery and the occult. The actual Stonehenge monument had captured public imagination through books like Erich von Däniken's "Chariots of the Gods?" (1968), which speculated about ancient astronauts and lost civilizations.

Altec named its flagship speaker after the monument and used marketing that blended ancient mystery with contemporary technology. This was unusual for Altec, but it followed the broader cultural trends of the era.

The Stonehenge III was Altec's attempt to build an audio artifact - a piece as visually compelling as it was sonically impressive.

Legacy

The Stonehenge III occupies a unique place in audio history:

Ultimate Statement Piece: Altec's most visually dramatic speaker
Technical Excellence: Features the legendary 604-8G driver
Cultural Artifact: Reflects 1970s fascination with mystery and the occult
Collector's Prize: Among the most sought-after vintage speakers
Design Icon: Monolithic cabinet design remains striking today

Collectors rank the Stonehenge III at the top of vintage Altec ownership, with its sound quality, craftsmanship, dramatic design and extreme rarity. Well-preserved examples command prices of $3,500-$5,000 or more, and exceptional specimens may exceed that.

Images

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Source 1: HiFi Wiki

Link: HiFi Wiki
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Attribution Required: Yes
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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.

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