Altec Lansing 938-8AD 8-Ohm Compression Driver
The Altec Lansing 938-8AD is a vintage high-frequency compression driver designed for professional sound reinforcement and cinema audio applications. Part of Altec's long-standing reputation for robust and sonically accurate drivers, the 938-8AD exemplifies the engineering excellence that defined mid-20th century audio technology. With its 8-ohm impedance and horn-loading compatibility, this driver was likely used in systems requiring high sensitivity and clear projection, such as the famed "Voice of the Theatre" speaker arrays.
Specifications
| Specification | Detail |
| Model | 938-8AD |
| Brand | Altec Lansing |
| Year of Introduction | Circa 1975 (exact year unknown) |
| Impedance | 8 ohms |
| Power Handling | Unknown |
| Sensitivity | Unknown |
| Frequency Response | Optimized for mid-to-high frequencies |
| Driver Type | Compression driver |
| Magnet Type | Likely Alnico (common in vintage Altec units) |
| Diaphragm Material | Likely phenolic resin |
| Mounting | Compatible with standard Altec horn flanges |
| Intended Use | Professional audio, cinema sound systems |
Historical Context
The Altec Lansing 938-8AD belongs to a lineage of high-performance compression drivers developed during the golden era of cinema and live sound reinforcement. Altec Lansing was a dominant force in professional audio from the 1940s through the 1970s, best known for its "Voice of the Theatre" (VOTT) systems that set the standard for clarity, efficiency, and durability in movie theaters and public address applications.
While the exact role of the 938-8AD in Altec's product lineup is not fully documented, its 8-ohm design and construction suggest it was intended for integration into multi-way systems where reliable high-frequency reproduction was critical. These drivers were often paired with large-format horns and complementary low-frequency cabinets to create full-range systems capable of filling large venues with minimal amplification.
Altec's use of Alnico magnets and phenolic diaphragms contributed to a warm, articulate sound signature that remains sought after by vintage audio enthusiasts and restorers. The 938-8AD reflects the company's commitment to engineering for longevity and sonic integrity under demanding conditions.
Sound Signature
The 938-8AD delivers a classic horn-loaded sound characterized by high efficiency, excellent transient response, and strong mid-to-high frequency projection. Users can expect:
- Clarity and articulation in vocals and instruments
- Extended high-frequency response with minimal distortion at high SPLs
- A forward and dynamic presentation typical of vintage Altec drivers
- Strong performance in speech intelligibility, making it ideal for cinema and PA use
When properly restored and paired with a suitable horn, the 938-8AD offers a window into the sonic character that defined professional audio for decades.
Maintenance and Restoration Tips
Due to its age, the Altec Lansing 938-8AD may require servicing to perform optimally. Common issues and recommended maintenance include:
- Diaphragm Replacement: Aging phenolic diaphragms can become brittle or delaminate. Replacing with a modern reproduction or carefully restored original is often necessary.
- Magnet Recharging: Alnico magnets can lose strength over time. Re-magnetizing can restore efficiency and output.
- Voice Coil Inspection: Check for signs of overheating, warping, or misalignment. Re-coning services are available from specialty restoration shops.
- Terminal and Wiring Check: Corrosion or loose connections at the terminal block can degrade performance. Clean and tighten as needed.
- Horn Compatibility: Ensure the driver is mounted on a compatible horn (such as Altec 802, 811, or similar) to achieve intended frequency response and dispersion.
Regular inspection and conservative use will help preserve the driver's integrity, especially if used in active vintage audio systems.
Collectibility and Market Value
The Altec Lansing 938-8AD holds moderate collectibility, rated 7/10, due to its association with Altec's professional audio legacy and its potential use in restoration projects. While not as iconic as the 150-series or 285 drivers, it remains a valued component among vintage PA and cinema speaker enthusiasts.
- Market Value: $100–$300 per driver, depending on condition, originality, and completeness
- Demand: Steady among restorers and vintage audio hobbyists
- Rarity: Moderate — not mass-produced for consumer markets, but not exceptionally rare
Drivers in original, unmodified condition with intact labels and hardware command higher prices.
Conclusion
The Altec Lansing 938-8AD is a testament to the engineering rigor and sonic excellence that defined Altec's professional audio division. While specific documentation is limited, its design and construction align with the standards of a company that shaped the sound of mid-century cinema and live sound. For collectors, restorers, and vintage audio enthusiasts, the 938-8AD offers both historical significance and the potential for exceptional performance when properly maintained.
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