Altec 288 Compression Driver

The Altec 288 is a large-format compression driver with a 1.75-inch diaphragm and a big Alnico V magnet. It was used in cinema and professional audio for decades, and it was the driver in the Voice of the Theatre systems and many other professional installations worldwide.

Specifications

Type	Large Format Compression Driver
Diaphragm Diameter	1.75 inches (44.5mm)
Voice Coil Diameter	2.80 inches (71mm)
Throat Diameter	1.4 inches (36mm)
Magnet	Alnico V (3.4 lbs / 1.54 kg)
Gap Flux Density	2.05 Tesla (at rest)
Nominal Impedance	8 Ω (288-8) / 16 Ω (288-16)
Power Handling	15W continuous
Frequency Response	500 Hz - 15 kHz
Sensitivity	~110 dB/W/m
Weight	~13.3 kg (29.3 lbs)
Outside Diameter	7.1 inches (180mm)

Design Overview

The 288 is American compression driver design from Altec's best years. The Alnico V magnet structure is massive, and the components are precision machined. Altec used it as the standard for cinema and professional sound.

Key design features include:

Large Alnico Magnet: 3.4-pound Alnico V magnet provides exceptional magnetic stability and flux density
Aluminum Diaphragm: Precision-formed aluminum with tangential suspension for smooth, extended response
High Efficiency: ~110 dB sensitivity allows modest amplifiers to achieve cinema-level SPLs
Robust Construction: Built to withstand the demands of continuous professional use

Applications

The 288 sat at the center of Altec's best-known systems:

Voice of the Theatre A7 - The legendary cinema speaker
Voice of the Theatre A5, A4 - Smaller VOTT variants
Model 19 - Home speaker version
Professional cinema installations worldwide
Early recording studio monitors

In the Wild

Featured in Resistor Magazine's restoration profile of Iwan Arjanto's vintage speaker collection. The Altec 288 was the driver that started Arjanto on horn-loaded speakers.

"The first time I heard an Altec horn was at my friend's house - he used to play around with full range drivers too - after hearing that horn I couldn't forget its sound. That's when the journey began, I began hunting many horns."

— Iwan Arjanto

Arjanto's first horn-type speaker purchase was a Fostex FD600, because it was affordable. The Altec 511 horn (typically used with the 288 driver) is what opened his ears to horn-loaded systems. He has since built four pairs of Altec A7 speakers for customers, each using the 288 compression driver on the 811B sectoral horn.

Variants

288B: Common early version used in VOTT systems
288-8G / 288-16G: Later "G-series" versions with 8Ω and 16Ω impedance options
288-8K / 288-16K: Later versions with ferrite magnets (lighter weight, slightly different character)
288C: Specific version mentioned in some VOTT documentation

Historical Significance

The 288 was developed during Altec's heyday and became the reference standard for cinema sound. Its sound is dynamic, immediate and loud. The 288's efficiency (over 110 dB) meant theaters could reach realistic sound levels with relatively modest amplifier power.

Today the 288 is still highly sought after by horn enthusiasts and vintage audio collectors.