Altec 811 Horn Family

The Altec 811 series of sectoral exponential horns is best known for the distinctive "snout" of the 811B. This horn family defined cinema sound, and horn enthusiasts still go looking for them.

The 811 Series

Altec 811B

The classic "Voice of the Theatre" horn. Heavy cast construction, 90° x 40° coverage, and the long-throw snout design. It was 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 the same basic design principles:

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, made the "Voice of the Theatre" sound that ran through 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 good sound systems. The design sold well enough that it stayed in production for decades, and it 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 lasting performance - even decades-old examples can sound exceptional when properly maintained.

Compatible Drivers

The 811 series horns are made 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
License: Varies - check individual image
Attribution Required: Yes
Commercial Use: Unknown - verify on site
Notes: User-contributed content. Attribution recommended.

Source 2: HiFi Engine

Link: HiFi Engine
License: User-contributed manuals
Attribution Required: Yes
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
Notes: Verify license before use.

Source 4: Radio Museum

Link: Radio Museum
License: User-contributed
Attribution Required: Yes
Commercial Use: Unknown
Notes: Attribution required for user photos.

Attribution Notice: This page links to external image sources. When using images from these sources, make sure you comply with their license terms. CC0 images require no attribution. CC BY and CC BY-SA images require attribution.

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Documentation

Altec Datasheets - Technical specifications
811B Driver Page - Detailed information