Altec Lansing 291-16A / 291-16B (1970–1975)

At 9.1 kilograms and 18,500 gauss of magnetic fury, this driver doesn’t whisper—it commands.

Overview

The Altec Lansing 291 series isn’t a speaker you casually drop into a bookshelf. It’s a compression driver built for scale, born in the theater and industrial sound world where 131 dB SPL at 40W isn’t a boast—it’s a baseline. Introduced first as the 291-16A in 1970 and followed by the higher-powered 291-16B in 1975, these 16-ohm beasts were engineered to drive large horns in high-output environments. They’re heavy—just over nine kilos each—with a physical presence that matches their acoustic intent. The driver’s core design centers on brute-force efficiency: a flat aluminum ribbon voice coil wound edge-wise, a massive alnico magnet structure producing 18,500 gauss, and a voice coil diameter of 7.1cm that speaks to serious thermal and mechanical headroom.

While visually similar, the 291-16A and 291-16B are not identical. The later 291-16B doubles the power handling to 80W and slightly adjusts the frequency output, rolling off at 14 kHz compared to the 16A’s 16 kHz upper limit. Both share the same 500 Hz lower crossover point and are rated at 117 dB/W/m sensitivity, making them efficient partners for large horn systems. Owners report using them with Altec’s own 311-90, 311-60, and 329A horns, often paired with N-500F networks or custom crossovers. The 291-16A launched with a Symbitik diaphragm—a hybrid of polymid film and aluminum alloy—derived from the 288D, promising wide bandwidth and sharp transient response. However, collectors note that Altec also offered a more durable, less sonically refined diaphragm for high-power applications, suggesting a split personality: one tuned for fidelity, the other for endurance.

Despite their capabilities, the 291s never achieved the cult status of the 288 series. Some forum discussions suggest they offered little sonic advantage over the 288 beyond increased power handling, making them a niche choice even in their prime. That lack of widespread acclaim may have helped preserve surviving units—many still turn up with original diaphragms and intact lead-ins, though the fragile internal conductors remain a known weak point.

Specifications

Key Features

18,500 Gauss Alnico Magnet Structure

The 291’s magnetic system is its beating heart. At 18,500 gauss, the alnico magnet delivers intense flux density, ensuring tight control over the voice coil even at high excursions. This isn’t just about loudness—it’s about linearity under load. The field strength contributes directly to the driver’s 117 dB/W/m efficiency and its ability to sustain 131 dB SPL without compression. Alnico’s smooth saturation characteristics also help avoid the harshness that can creep in with ceramic magnets at high drive levels, giving the 291 a reputation for clean, dynamic output when paired with the right horn.

Symbitik Diaphragm with Polymid-Aluminum Composite

The 291-16A debuted with a Symbitik diaphragm, a composite of polymid film and aluminum alloy. This hybrid construction aimed to marry the rigidity of metal with the damping properties of polymer, reducing breakup modes and extending high-frequency response to 16 kHz. The design was derived from the 288D, but tuned for higher power. However, owners report Altec also supplied a more durable, sonically duller diaphragm for high-power installations—suggesting a trade-off between longevity and fidelity. The OEM diaphragm part number 21531 remains available as NOS stock, a small mercy for restorers.

Edge-Wound Flat Aluminum Ribbon Voice Coil

Wrapped around a 7.1cm former, the edge-wise wound flat aluminum ribbon voice coil is a hallmark of Altec’s high-power engineering. This design increases surface area for better heat dissipation and reduces mass compared to round wire, improving transient response. Combined with the large magnet gap, it allows the 291-16B to handle 80W—twice the input of many contemporaries. The coil’s construction also contributes to the driver’s deep 124–126mm profile, a physical reminder of its industrial roots.

Reinforced Lead-In Wires (and Their Failure Modes)

One of the most commonly reported failure points is the lead-in wires—thin, stiff conductors that connect the voice coil to the terminal. Over time and thermal cycling, these can fatigue and break, especially near the coil attachment. Forum posts confirm this as a widespread issue, prompting later re-engineering in successor models. Repair is possible but delicate, often requiring disassembly and careful splicing. The fragility underscores that while the 291 was built for power, it wasn’t immune to the material limits of its era.

Historical Context

The 291-16A emerged in 1970 as part of Altec’s push into high-power cinema and public address systems. The 291-16B followed five years later with doubled power handling, reflecting the growing demand for louder, more reliable sound reinforcement. Though technically advanced, the 291 series appears to have occupied a narrow niche. Some owners suggest it offered little sonic improvement over the more celebrated 288 series, with the primary advantage being increased power tolerance. This may explain its lower profile in audiophile circles despite its robust engineering.

Collectibility & Value

Current market prices vary widely based on condition and variant. A 291-16A listed as “original excellent” fetched CA$2,250 on Canuck Audio Mart, while another sold for $1,425 on PicClick.ca. The rarer 291-16K variant appeared at $225, suggesting significant model-specific value differences. NOS diaphragms (OEM 21531) are available from private sellers, a critical resource given the known lead-in wire failures. No official data on common maintenance issues exists, but community knowledge emphasizes inspecting the internal conductors before purchase. With no modern equivalent, the 291 remains a specialist’s driver—valued not for nostalgia, but for its uncompromising engineering.

eBay Listings

Altec 291-16B Compression Driver – Single – Original Diaphra

$500

VINTAGE ALTEC 291-16K HORN SPEAKER DRIVER 16 ohm #2

$300

ALTEC LANSING 291-16K DRIVERS - ORIGINAL & VERY CLEAN

$795

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