Altec 811 Horn Family

Name: Altec 811 Horn Family
Brand: Altec

The Altec 811 series of sectoral exponential horns represents one of the most iconic designs in professional audio history. Best known for its distinctive "snout" appearance in the legendary 811B, this horn family defined cinema sound and remains highly sought after by horn enthusiasts today.

The 811 Series

Altec 811B

The classic "Voice of the Theatre" horn. Massive cast construction, 90° x 40° coverage, and the iconic long-throw snout design. Used in A7 cinema systems and Model 19 home speakers.

90° H x 40° V coverage pattern
1.4" throat for 288-series drivers
~30 lbs cast metal construction
Straight exponential throat

Design Philosophy

All 811-series horns share common design principles that contributed to their legendary sound:

Exponential Flare: Precise exponential expansion matches acoustic impedance for maximum efficiency
Straight Throat: No bends or folds means minimal phase distortion
Sectoral Pattern: Controlled 90° x 40° coverage fills theater seating while minimizing reflections
Massive Construction: Heavy cast metal prevents resonance and ensures decades of consistent performance

The Voice of the Theatre Sound

The 811 horn, paired with the Altec 288 compression driver, created the signature "Voice of the Theatre" sound that defined cinema audio from the 1940s through the 1970s. This combination delivered:

Exceptional dialog intelligibility
Wide dynamic range from subtle to explosive
Even coverage throughout theater seating
Low distortion at high SPLs
Instantaneous transient response

Historical Significance

The 811 horn was developed during the post-war cinema boom when thousands of theaters needed high-quality sound systems. The design proved so successful that it remained in production for decades and influenced horn design across the industry.

Key historical points:

Introduced in the late 1940s
Standard equipment in Voice of the Theatre systems
Installed in thousands of movie theaters worldwide
Remained in production into the 1970s
Still highly sought after by vintage audio enthusiasts

In the Wild

Featured in Resistor Magazine's profile of vintage speaker restorer Iwan Arjanto, who has built multiple pairs of Altec A7 speakers using original 811B horns. The horns are prized for their enduring performance—even decades-old examples can provide exceptional sound quality when properly maintained.

Compatible Drivers

The 811 series horns are designed for Altec's large-format compression drivers:

Altec 288 - The classic pairing
Altec 291 series - Later professional drivers
Various aftermarket diaphragms available for restoration

Modern Use

Today, vintage 811 horns are prized by:

Horn loudspeaker enthusiasts
Vintage cinema collectors
DIY speaker builders
Professional studios seeking classic Altec sound

Related Horns

Altec 511B - Compact sibling with same coverage pattern
511 Horn Family - The compact alternative

Images

The following sources may have images of this equipment. Always verify license terms and provide proper attribution when required.

Source 1: HiFi Wiki

Link: HiFi Wiki
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Attribution Required: Yes
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Source 2: HiFi Engine

Link: HiFi Engine
License: User-contributed manuals
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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
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Source 4: Radio Museum

Link: Radio Museum
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Commercial Use: Unknown
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