Altec Lansing 34647 Compression Driver
The Altec Lansing 34647 is a high-efficiency compression driver from the golden era of professional audio. Nobody has documented the exact year it was introduced. It was likely produced in the 1960s to early 1970s. Altec built these drivers for cinema sound, public address systems, and high-performance studio monitoring. The 34647 has a tough build and a dynamic output.
Specifications
| Feature | Specification |
| Type | Compression Driver |
| Frequency Response | 1.5 kHz – 18 kHz (typical with horn) |
| Power Handling | 20W – 100W (depending on system integration) |
| Impedance | 8 ohms or 16 ohms (model variant dependent) |
| Sensitivity | 104 – 108 dB (1W/1m) |
| Diaphragm | Phenolic resin |
| Voice Coil | 1-inch throat |
| Magnet Type | Alnico (Aluminum-Nickel-Cobalt) |
| Horn Compatibility | Exponential horns (e.g., Altec 802, 811) |
| Mounting | 4-screw flange (standard Altec pattern) |
Historical Context
The Altec Lansing 34647 belongs to Altec's broader family of professional drivers for commercial and industrial audio. In the mid-20th century, Altec dominated the cinema and theater sound market. Drivers like the 34647 were frequently paired with large-format horns and bass enclosures. That gave full-range systems with high sound pressure levels and minimal amplifier power.
It has an alnico magnet and a phenolic diaphragm, which fits the materials and design thinking of the time - efficiency, durability and clarity. The 34647 was often used with Altec's 515B or 518B crossover networks and paired with horns such as the 802A or 811A for dispersion and response.
These drivers turned up in movie theaters, train stations, auditoriums, and even early rock concert PA systems. Their high sensitivity suited places where amplifier power was limited but wide coverage was essential.
Sound Signature
The 34647 has a bright, articulate, dynamic high-frequency response with a midrange presence that many describe as "lively" or "forward." Its alnico magnet contributes a smooth, warm tonality that balances the natural brightness of the phenolic diaphragm. With a compatible horn and crossover, the driver offers exceptional clarity and projection.
Because of its high efficiency and extended high-frequency response, the 34647 can sound harsh or fatiguing with poorly designed horns, mismatched crossovers, or excessive amplifier power.
Maintenance and Restoration Tips
Like all vintage audio components, the Altec 34647 needs a careful evaluation and possibly restoration before it will work reliably in a modern system:
- Diaphragm Inspection: The phenolic diaphragm is prone to aging, warping, or cracking. If distorted or damaged, replacement with a modern equivalent (e.g., from Hahn or OEM restorers) is recommended.
- Alnico Magnet Recharging: Over decades, alnico magnets can lose strength. Re-magnetizing using a proper magnetizer can restore original efficiency and output.
- Terminal and Wiring Check: Inspect for corrosion, loose connections, or brittle insulation. Clean terminals with contact cleaner and replace wiring if necessary.
- Horn Matching: Use with original Altec exponential horns for authentic response. Avoid modern plastic horns that alter dispersion and tonality.
- Power Handling: Do not exceed 100W, and ensure amplifier impedance matches the driver (8Ω or 16Ω). Use a crossover to prevent low-frequency damage.
- Environmental Care: Store and operate in dry, temperature-stable environments to prevent diaphragm warping and corrosion.
Collectibility and Market Value
The Altec 34647 has moderate collectibility among vintage audio enthusiasts, especially those restoring classic theater systems or building high-efficiency horn speakers. Its collectibility rating is 7/10. It is valued more for its utility and historical role than as a rare collector's item.
- Market Value: $100 – $300 per driver, depending on condition, originality, and diaphragm status.
- Restored Units: Drivers with replaced diaphragms or recharged magnets may command higher prices if professionally serviced.
- Demand: Steady among DIY horn speaker builders and vintage PA restorers.
Conclusion
The Altec Lansing 34647 is a respected driver among vintage audio enthusiasts for its efficiency and clarity. It is not as widely known as the 285 or 802 drivers.
Market Value
┌──────────────────────────────────────────────────────────────────────────┐ │ ALTEC 34647 Nov 2026 │ ├──────────────────────────────────────────────────────────────────────────┤ │ High $566 Latest $260 │ │ Median $500 Trend — │ │ Low $40 Volume ~2/mo │ ├──────────────────────────────────────────────────────────────────────────┤ │ $600 ┤ │ │ │ . . │ │ │. │ │ $343 ┤ │ │ │ .│ │ │ │ │ │ │ │ $0 ┤ . │ │ ├─────────────────────────────────────────────────────────────────│ │ vol │█ █ █ █ █│ │ └─────────────────────────────────────────────────────────────────│ │ 2026-02 2026-03 2026-04│ └──────────────────────────────────────────────────────────────────────────┘
eBay completed sales. Excludes accessories, parts, and non-working units. Hover points for details.
eBay Listings
Recently sold on eBay: $40–$566 (median $500, based on 5 completed sales, past 12 months)
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