Altec 902 & 902-8B Compression Drivers

Name: Altec 902-8b
Brand: Altec

1980s - 1990s

The Altec 902 and 902-8B are high-frequency compression drivers that represent the evolution of Altec's famous compression driver technology into the ceramic magnet era. These drivers were widely used in professional sound reinforcement, studio monitoring, and high-end home audio systems during the 1980s and 1990s.

Specifications

Type	High-frequency compression driver
Throat Diameter	1.4" (35mm)
Diaphragm Material	Aluminum or phenolic
Voice Coil Diameter	2" (50mm)
Magnet Type	Ceramic (ferrite)
Magnet Weight	Approximately 4.5 lbs (2.0 kg)
Nominal Impedance	8 Ω (902-8B), 16 Ω (902-16B)
Power Handling	30W AES, 60W program
Sensitivity	110 dB SPL (1W, 1m)
Frequency Response	500 Hz - 18 kHz
Recommended Crossover	800 Hz or higher
Weight	Approximately 8 lbs (3.6 kg)

Design Evolution

The 902 series represents Altec's transition from Alnico magnets to ceramic (ferrite) magnets. This change was driven by several factors:

Cost Reduction: Ceramic magnets were less expensive than Alnico
Supply Stability: Alnico supplies became less predictable in the 1970s-1980s
Performance Consistency: Ceramic magnets offered more consistent magnetic properties
Temperature Stability: Ceramic magnets are less affected by temperature changes

Despite the change in magnet material, the 902 series maintained the essential design principles of Altec's earlier compression drivers, including the precision phase plug and robust diaphragm assembly.

902 vs 902-8B Differences

Feature	902	902-8B
Production Era	Early 1980s	Mid-late 1980s
Diaphragm	Early aluminum design	Improved aluminum design
Voice Coil	Standard design	Enhanced heat dissipation
Phase Plug	Conventional design	Optimized design

Technical Features

Phase Plug Design: Precision-machined phase plug for smooth frequency response and controlled dispersion
Diaphragm Assembly: Aluminum diaphragm with edge-wound voice coil for high efficiency and power handling
Magnet Structure: Large ceramic magnet providing strong magnetic field for high sensitivity
Cooling System: Improved thermal management for continuous high-power operation
Mounting: Standard Altec bolt pattern for compatibility with 811B, 511B, and other Altec horns

Common Applications

The 902/902-8B drivers were used in numerous Altec systems:

Studio Monitors: 9844-8B, 9846-8B, and other professional monitors
Sound Reinforcement: Concert systems, theater installations
Home Audio: Custom installations and DIY projects
Guitar Amplifiers: Some high-end guitar cabinets

Comparison with Earlier Models

Driver	Magnet	Era	Characteristics
802D/G	Alnico	1950s-1970s	Warm, smooth character; collector favorite
806A	Alnico	1960s-1970s	Similar to 802 but with different diaphragm
902/902-8B	Ceramic	1980s-1990s	More detailed, slightly brighter, higher power handling
909-8A	Ceramic	Late 1980s	Tangerine phase plug, Pascalite diaphragm

Sound Characteristics

Owners and engineers describe the 902/902-8B as:

Detailed and Transparent: Excellent high-frequency extension and clarity
Efficient: 110 dB sensitivity allows for high output with modest amplifier power
Robust: Capable of handling high power levels in professional applications
Slightly Brighter: Compared to Alnico models, some describe them as having more "sparkle"
Versatile: Works well across various applications from studio to live sound

Maintenance and Restoration

Common maintenance issues with 902/902-8B drivers include:

Diaphragm Replacement: Original diaphragms (26420 for 8Ω, 26421 for 16Ω) are still available
Magnet Charging: Ceramic magnets generally don't lose charge like Alnico
Cleaning: Phase plug slots can accumulate debris affecting performance
Gasket Replacement: Original gaskets may deteriorate over time

Legacy

The 902/902-8B represents the culmination of Altec's compression driver technology before the company's decline in the 1990s. These drivers are still highly regarded today for their:

Professional Reliability: Built for continuous use in demanding environments
Technical Performance: Excellent specifications for both home and professional use
Historical Significance: Last of the classic Altec compression driver designs
Collector Value: Sought after by vintage audio enthusiasts and professionals

While some purists prefer the character of earlier Alnico models, the 902/902-8B offers exceptional performance with modern reliability. They remain popular in both original systems and DIY projects, with used pairs typically selling for $300-$500 depending on condition.