Altec 515 (1966–1979)

At 11.8 kilograms and with a 389mm face, this driver is built for authority, not subtlety.

Overview

The Altec 515 isn't a single speaker. It's a lineage of high-output, horn-optimized 15-inch low-frequency drivers that evolved over decades. People often call it the "Altec 515" generically, but the model exists in distinct iterations. The main ones are the 515B, released in 1966, and the 515C, introduced in 1979. Each refined power handling and construction a bit. These are not bookshelf parts or passive radiators for compact enclosures. They are industrial-grade units made for deep, controlled bass in large horn systems. Owners report the 515B and 515C as the most powerful 15-inch cone woofers in Altec's lineup at their respective times, built to withstand serious thermal and mechanical stress while staying linear under high excitation.

The 515 designation spans very different eras and engineering approaches. A Facebook post from a long-time collector claims the 1949 Altec 515 is "the most musical low-frequency speaker ever made," but no technical data exists for that early version in the verified records. By the mid-1960s, Altec had standardized the 515B as a 38 cm (15-inch) cone woofer with a 76mm voice coil, 16 Ω impedance, and a frequency range from 20 Hz up to 1 kHz. The later 515C kept the same core dimensions and frequency range but raised allowable input from 50W to 75W, which suggests better thermal management or suspension durability. Both were designed for horn loading, not free-air or sealed-box use. They were commonly paired with Altec's 288, 290, or 802 high-frequency drivers on 500 Hz crossover horns, as documented in the 1957 catalog.

Specifications

Key Features

Alnico V Magnetic Circuit with 14,750 Gauss Flux Density

The 515's magnetic system is built around an Alnico V magnet, and it generates 14,750 gauss of magnetic flux density. That high field strength gives strong motor control over the voice coil, which means tighter bass response and better transient accuracy. Unlike ferrite or modern neodymium designs, Alnico magnets are prized for their smooth saturation characteristics, which some engineers argue give a more natural decay of low-frequency energy. The magnetic circuit is designed for horn loading. That means it favors efficiency and control at high sound pressure levels over maximum excursion in open air.

76mm Voice Coil for High Power Handling

The voice coil is 76mm in diameter, which is exceptionally large for a 15-inch driver of its era. It was engineered to dissipate heat efficiently and stay stable under prolonged high-power input. The 515B's 50W allowable input and the 515C's 75W rating reflect this. Add a rated input of 35W across variants, and the driver was clearly meant for professional or high-end domestic systems where sustained output mattered. The large coil also means higher inductance, which may slightly roll off the top of the 1 kHz upper limit. The recommended 500 Hz crossover point mitigates that.

38 cm Cone with 25Hz Resonance for Deep Bass Extension

The 515 reproduces frequencies down to 20 Hz, with a free-air resonance of 25Hz. That is real sub-bass performance, and rare for cone drivers of its time. The low resonance comes from a compliant suspension and high moving mass, both optimized for horn-loaded cabinets like the 825B (A7), where the horn's loading effect further extends low-end response. The 389mm external diameter puts it in the 15-inch category, though some variants, such as the 515-G series, list a 16-inch diameter (406mm). That suggests dimensional tolerances or different mounting configurations. The 515-G series also lists a depth of 6-1/16 inches (155mm) and a weight of 30 pounds (13.6kg), slightly heavier than the 515B and 515C, possibly due to a larger magnet or reinforced basket.

Historical Context

The Altec 515 came out of a lineage of professional-grade loudspeakers developed for theater, broadcast, and high-fidelity reproduction. Its place in the 1957 Altec catalog as a component in speaker systems, paired with high-frequency drivers on 500 Hz horns, confirms its role in full-range, high-efficiency designs. It was not a standalone consumer product. It was a modular unit for system builders. By 1966, the 515B was the peak of Altec's 15-inch cone woofer technology, billed as the most powerful in the company's lineup. The 1979 release of the 515C suggests continued demand for high-output, horn-compatible drivers even as solid-state amplification and new enclosure designs began to dominate the market. Thiele-Small parameters have not been published, which is common for Altec drivers of this era.

Collectibility & Value

No official collectibility data exists in the fact sheet, but market listings indicate strong demand for early Altec 515 units. A matched pair of 1940s Altec Lansing 515s in "Red/White/Blue" trim was listed for sale on Reverb, and individual units from 1953 have been offered at €2,000 and $2,299. Owners report that the GPA/Altec 515 is considered "the ultimate woofer" when used outside standard VOTT cabinets, with one user describing a system using ten 515s per side as a "real killer" for deep bass. Another claims a system with a GPA Altec 515-8C "will crush any of the current 'high-end' speakers I've heard anywhere near the price." No data on common failures, maintenance issues, or long-term reliability is available, and original pricing documentation remains absent.

eBay Listings

Altec 515,604,604b replacement Cone paper kit

$200

ALTEC 515,604,604B replacement cone kit 1pc

$225

Vintage Altec Lansing 515B Speaker 15” Voice Of The Theater

$1,200

ALTEC A5 H110 515 288B 805 N500C Voice of Theatre Speaker Pa

$40,000

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