Altec 291-16B
A high-frequency compression driver that will embarrass most modern tweeters on a single watt, and a magnet structure that explains why the B is worth hunting over the A.
Overview
The Altec 291-16B is a big-format 1.4-inch high-frequency compression driver. It was never meant for a bookshelf. Altec built it for serious sound reinforcement, and the documentation makes that plain: it is engineered for durability and efficiency, not delicate audiophile tinkering. It is rare, powerful, and highly collectible, and it sits in the Altec hierarchy just below the 288-16G, which is generally regarded as the company's top-tier HF driver. The gap matters less than it sounds, because the 291-16B still commands respect for its build and its substantial output potential.
The 291-16B is not really a standalone product. It is half of a system. The driver's performance depends heavily on the horn it is mounted to, and the numbers show it. Mounted on a 311-60 horn, the 291-16B produces 129.5 dB at 4 feet (1.2m) on a single watt of input. On a 203B horn, output measures 121.5 dB at 10 feet (3m), again on one watt. Even at 30 feet (9m), with an 803B horn, the driver still manages 111.0 dB. That is louder at thirty feet than most domestic speakers get at three. The horn is a core part of the system's acoustic identity, and buyers who treat it as an afterthought will not hear what the driver can do.
The physical package is substantial for a compression driver. At approximately 28 lbs (12.7 kg), it has real heft, and the 2.8-inch voice coil is the reason. That coil diameter contributes to the driver's thermal handling, and it is what lets the 291-16B survive sustained high-power signals. The rated power handling is 40 watts. Some less authoritative sources claim figures as high as 50W RMS or even 80W, but those numbers are unconfirmed and conflict with each other. The 40-watt figure is the one that holds up. The 16-ohm impedance is consistent across all verified sources with no conflicting data, which makes it easy to plan around.
Key Features
2.8-Inch Voice Coil and 40-Watt Power Handling
The voice coil is where the 291-16B earns its keep. At 2.8 inches in diameter, it is a large-format coil, and that size supports the rated 40-watt power handling while contributing to the driver's ability to remain stable under load. The design logic here is straightforward: a bigger coil has more surface area to dissipate heat, which means it can take more sustained input before thermal failure. That is exactly the trait you want in a driver that lives in a PA cabinet running for hours at a time. The trade-off, as the documentation notes, is that the coil size suggests a design prioritizing durability over ultra-fast transient response — this is a driver built for live sound rather than critical studio monitoring. Owners who expect ribbon-tweeter speed from it are looking at the wrong tool.
16-Ohm Impedance for Parallel Arrays
The 16-ohm impedance rating is one of the 291-16B's most practical features. In professional audio systems of the era, running multiple drivers in parallel was standard practice, and 16 ohms made that safe. Two drivers in parallel present 8 ohms, four present 4 ohms, and amplifiers of the period could handle those loads without complaint. That is why the 291-16B shows up in multi-driver arrays and stacked horn configurations rather than as a single point source. Every verified source agrees on 16 ohms, with no contradictory measurements.
Horn-Dependent Output: 129.5 dB on One Watt
The 291-16B makes a lot of sound from almost no power. With a 311-60 horn, it peaks at 129.5 dB at 4 feet on 1 watt, which places it among the most efficient configurations documented for any vintage HF driver. Pressure sensitivity is rated at 108 dB SPL (1W/1m). The 311-90 and 1003B horns yield slightly lower output, topping out at 126.0 dB at 4 feet, which suggests a trade-off in directivity or throat coupling rather than any deficiency in the driver itself. This efficiency made the 291-16B a good fit for large venues before high-powered solid-state amplifiers, when a few watts had to fill a theater.
Big-Format 1.4-Inch Throat and Alnico Magnet
The 1.4-inch throat diameter puts the 291-16B in big-format territory, and it is designed to push serious air when mated to large-format horns. The magnet is Alnico. There is also a real difference between the 291-A and the 291-16B: collectors note that the B version has a much larger magnet and other differences, which matters if you see the two referenced interchangeably while shopping. The gasket specification groups the 291-16B with the 288-16G and 290E - gaskets No. 1 through No. 3 cover all three - which is a useful cross-reference for sourcing parts or swapping drivers between horns.
Historical Context
The 291-16B was built as a high-frequency compression driver for serious sound reinforcement, and its efficiency made it a fit for large venues in an era before high-powered solid-state amplifiers were commonplace. Contemporary coverage in Recording Engineer (June 1974, p.57) noted that improvements in top plate and phasing plug designs allowed Altec compression drivers of this era to exhibit more uniform and extended performance. It sits below the 288-16G in Altec's hierarchy, but it was not a budget alternative. It was a working driver with a specific role in wide-range two-way systems. The documentation describes it as designed for high-quality sound systems, and it shows up in real installations: the Klipsch MCM 1900 Loudspeaker System used 291-16B drivers as its high-frequency components.
Collectibility & Value
The 291-16B is considered hard to find, especially in original condition with intact diaphragms. Collectors and restorers note that original units with intact diaphragms are increasingly rare. One listing carried the blunt condition note "Original Diaphragms SOLD." Prices reflect that scarcity. A December 2025 listing on US Audio Mart priced a single unit at USD $800.00, while earlier listings show a pair offered for $950 OBO in 2021 and a single unit at $675 in 2022. A pair was also offered at 600 Euros plus shipping from Tallinn, Estonia, and a single unit drew a bid of ¥88,000 on Yahoo Auctions in March 2024. The market is niche but active, driven by restorers and vintage PA enthusiasts rather than casual collectors.
Inspect carefully before buying. Creaky surrounds, corroded terminals, or damaged diaphragms can render a 291-16B unusable without expert repair, and the cost of that repair can easily exceed the purchase price. Factory replacement parts are noted to exist, but availability is not confirmed. Aftermarket diaphragms are available - Orange County is the commonly cited source - and original diaphragms are described as "simbio Tec" type. One owner reported that a single alnico unit with an aftermarket diaphragm "sounds great," which suggests the aftermarket route is viable when originals cannot be found.
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