Altec Lansing 511B Horn

The Altec Lansing 511B is a legendary multicell compression horn that epitomizes the golden era of professional audio engineering. Designed in the 1950s and produced through the 1970s, this horn became a staple in recording studios, movie theaters, and high-fidelity audio systems. Known for its precision engineering and robust aluminum construction, the 511B delivers exceptional clarity and projection when paired with compatible drivers such as the Altec 802, 806, or 808.

Specifications

Feature	Specification
Model	511B Horn
Brand	Altec Lansing
Production Era	1950s–1970s
Type	Passive multicell horn
Construction	Cast aluminum
Crossover Frequency	500 Hz (typical)
Dispersion	90° horizontal × 40° vertical
Compatibility	Designed for use with Altec 802, 806, 808 compression drivers
Power Handling	N/A (depends on driver used)
Impedance	N/A (determined by driver)
Sensitivity	High efficiency (varies with driver; typically 108–112 dB/W/m with Altec drivers)
Weight	~15 lbs (6.8 kg)
Finish	Natural aluminum (may show patina with age)

Historical Significance

The Altec 511B horn was developed during a transformative period in audio history, when sound reinforcement and cinematic audio demanded reliable, high-output solutions. As part of Altec’s renowned "Voice of the Theatre" series, the 511B was engineered to provide controlled directivity and minimal distortion, making it ideal for critical listening environments.

Its multicell design—featuring a grid-like pattern of individual horn channels—allowed for precise dispersion control, reducing off-axis coloration and ensuring even coverage across large venues. This made the 511B a favorite in broadcast studios, dubbing theaters, and live sound applications throughout the mid-20th century.

Even today, the 511B remains highly sought after by vintage audio enthusiasts and professional restorers for its authentic reproduction of the classic "West Coast" sound—characterized by a forward, dynamic midrange and crisp high-frequency articulation.

Sound Signature

When mated with original Altec drivers like the 802 or 808, the 511B produces a vivid, punchy sound with exceptional presence. Its aluminum throat and rigid structure contribute to low resonance and fast transient response, resulting in clear vocal reproduction and strong projection.

However, due to its high efficiency and extended high-frequency response, the 511B can sound bright or harsh if paired with modern drivers or used without proper equalization. Many users implement mild attenuation or use tube-based amplification to soften the top end and achieve a more balanced tonal character.

Common Issues and Maintenance Tips

While the 511B is built to last, decades of use and storage can lead to several common issues:

Aluminum Corrosion: Though resistant, the cast aluminum body can develop surface oxidation or pitting, especially in humid environments. Clean gently with a non-abrasive aluminum polish.
Denting or Warping: The horn's mouth is susceptible to dents during handling. Avoid physical impact and store securely.
Driver Compatibility and Condition: The horn itself is passive, but the compression driver is critical. Original Altec drivers may require reconing or diaphragm replacement. Always inspect the driver’s phase plug and surround before use.
Mounting Hardware Wear: Check U-brackets and mounting screws for fatigue or stripping. Replace with period-correct or reinforced hardware if necessary.
Dust and Debris: Clean the throat and cells carefully with compressed air or a soft brush to prevent obstruction.

Pro Tip: For optimal performance, pair the 511B with a matching low-frequency enclosure (such as an Altec 604 or 605) and use a passive crossover set at 500 Hz. Bi-amping with modern DSP control can also tame brightness and improve integration.

Collectibility and Market Value

The Altec 511B horn holds a collectibility rating of 8/10, prized for its historical importance, build quality, and sonic character. Units in good condition—with original finishes and included drivers—typically sell between $200 and $500. Fully restored sets with working 808 drivers or rare finishes can exceed $600 in the collector market.

Enthusiasts value complete, matching-number systems, and horns sourced from decommissioned theaters or studios often carry premium appeal.

Conclusion

The Altec Lansing 511B horn stands as a benchmark in professional horn design. Its combination of engineering excellence, durability, and sonic authority continues to influence modern loudspeaker development. Whether used in a vintage hi-fi setup or restored for studio monitoring, the 511B offers a direct link to the golden age of audio—delivering not just sound, but legacy.