Altec Lansing 615B (1968)

At 12.6kg, this coaxial brute delivers PA-grade punch with a horn that cuts through any room.

Overview

The Altec Lansing 615B isn't subtle. Introduced in 1968, it was built as a high-efficiency coaxial composite speaker unit for public address systems where raw output and reliability mattered more than nuance. Weighing in at 12.6kg, the 615B packs a 38 cm cone-type woofer mated to a horn-driven high-frequency unit, all in a single coaxial assembly designed to project sound evenly across large spaces. It shares DNA with the legendary 604 series, often described as a commercial-grade sibling built for durability and consistent performance in demanding environments. While not intended for hi-fi living rooms, its presence has been noted in professional settings — one Instagram user even spotted a pair standing in as Abbey Road-style monitors alongside Urei 811As, a testament to their sonic authority when repurposed.

Owners report the 615B was engineered for simplicity and serviceability, with the crossover network mounted directly on the speaker frame — a practical touch for field repairs. The high-frequency section uses a horn-type driver equipped with a "water-drop equalizer" known colloquially as the Meat Bonner, a design aimed at smoothing dispersion and achieving tight directional control. The compression driver itself features a phenolic diaphragm, a material choice intended to boost input resistance and withstand the thermal stress of continuous high-power operation. According to available documentation, the system is rated from 20 Hz to 12 kHz, with a crossover point fixed at 1.55 kHz, blending the 38 cm woofer and the HF horn into a unified front.

Despite its industrial origins, the 615B has surfaced in niche audio circles as a rare and imposing relic. Forum mentions label it a "rare Altec 615B duplex," suggesting limited production or distribution compared to its more famous relatives. It was not a consumer product in the traditional sense, but rather a workhorse built for installations where sound needed to travel — auditoriums, train stations, or large venues — and where 16 Ω impedance and 35W of allowable input provided compatibility with standard PA amplifiers of the era.

Specifications

Key Features

38 cm Cone Woofer with Phenolic Diaphragm HF Driver

The 615B combines a 38 cm (approximately 15-inch) cone woofer for low-frequency reproduction with a horn-loaded high-frequency unit, forming a true coaxial design where both drivers share a central axis. This layout helps maintain coherent wavefronts and consistent off-axis response, a critical feature in PA applications. The HF driver uses a phenolic diaphragm, a rigid and heat-resistant material that improves power handling and reduces distortion during extended operation. While the exact model numbers aren't confirmed in all sources, one Reddit contributor identifies the high-frequency section as an 806 compression driver paired with a 416-series woofer, aligning with Altec’s modular design philosophy of the time.

Meat Bonner Water-Drop Equalizer for Directional Control

Mounted on the horn throat is a device known as the "Meat Bonner" — a water-drop-shaped equalizer designed to smooth the high-frequency response and improve directional characteristics. This passive acoustic filter helps eliminate peaks and ensures a more uniform dispersion pattern, especially important in environments where sound must cover wide areas without hotspots or dropouts. The term appears in technical documentation and enthusiast discussions, suggesting it was an internal or colloquial name for a proprietary tuning element that contributed to the 615B’s focused projection.

On-Frame Crossover Network at 1.55 kHz

Unlike systems where crossovers are housed in external cabinets or behind baffles, the 615B integrates its crossover directly onto the speaker frame. This placement simplifies installation and servicing, allowing technicians to access and replace components without disassembling the entire enclosure. The crossover operates at 1.55 kHz, a relatively high point for a 38 cm woofer, indicating that the low-frequency driver is expected to perform cleanly well into the midrange. This design choice likely supports the system’s high-efficiency goals, minimizing phase anomalies and power loss in the signal path.

Commercial-Grade Duplex Coaxial Design

Often described as a commercial version of the more famous 604, the 615B emphasizes robustness and scalability over audiophile refinement. It was not marketed as a studio monitor or home speaker but as a reliable component in larger PA arrays. Its 16 Ω impedance allows for daisy-chaining multiple units without overloading amplifiers, and the 35W power rating reflects conservative engineering for continuous-use scenarios. The coaxial layout ensures that both low and high frequencies originate from the same point, reducing comb filtering in reflective spaces — a practical advantage in churches, theaters, or outdoor setups.

Collectibility & Value

Current market listings show the 615B commanding prices between $250 for a driver unit and $499.50 when paired with a cabinet, suggesting modest but growing interest among vintage PA collectors. Failures appear to be infrequent, with one Reddit user noting that the units are "pretty unlikely to go bad" under normal conditions, attributing replacements only to catastrophic circuit failures elsewhere. However, at least one AudioHeritage thread documents a failed woofer — "everything works except one woofer. Only the tweeter appears to make any sound at all" — indicating that while robust, the woofers are not immune to age-related deterioration. No data is available on spare parts availability or restoration complexity, but general speaker repair techniques for surround replacement may apply.

eBay Listings

Altec Lansing 615B Duplex / Coaxial Mint Condition, pair (No

$1,149

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