REL S/850 Subwoofer

The REL S/850 stands as the flagship achievement within the Serie S collection, a subwoofer meticulously engineered to deliver awe-inspiring power coupled with profound musical insight. While the S/550 provides a superb balance of Serie S virtues, the S/850 represents the ultimate expression of this design philosophy, pushing every performance parameter to its zenith. REL calls it the benchmark of the Serie S line, and it starts with a 12-inch CarbonAlloy™ active driver with a pure carbon fiber center cap, matched to a 12-inch down-firing Carbon/Carbon passive radiator.

This pairing is driven by an 850-watt Linear Class D amplifier that REL says can surge to 1,000 watts on peaks. More than just a powerhouse, the S/850 is built for exceptional speed, subtle nuance, and flawless integration with premium loudspeakers. Its remarkable capability to generate deep, richly textured bass while retaining incredible quickness and agility makes it the quintessential foundation for both sophisticated stereo setups and deeply immersive home cinema systems, unveiling the true scale and emotional core of music and movies.

Key Features

• 12” CarbonAlloy™ Driver: A forward-firing, long-throw 12” driver with a CarbonAlloy™ cone and a pure carbon fiber center cap in place of the solid aluminum moldings of earlier models, for lower moving mass and a stiffer cone.
• 12” Carbon/Carbon Passive Radiator: A downward-firing 12” flat-cone passive radiator built from carbon, glass fiber and closed-cell foam, with over 2.4 inches (60mm) of travel in each direction, for deep and effortless low-frequency extension.
• 850W Linear Class D Amplifier: A Class D output stage fed by a traditional power supply, producing 850 watts (RMS) of continuous output with a surge to 1,000 watts on demanding peaks.
• Signature REL Filter Networks: Incorporates REL’s acclaimed High Level Input employing PerfectFilter™ technology, guaranteeing seamless sonic blending with the main speakers.
• Wireless Freedom Ready: Compatible with REL’s optional Airship Direct wireless system, whose receiver plugs into a dedicated port on the amplifier panel and carries both the High Level and .1/LFE signals with zero compression.
• Reference Line Array Capable: Purpose-built for stacking, allowing the creation of vertical arrays (up to three units high per channel) for the ultimate bass performance.

The Synergy of Motion: Active Driver & Passive Radiator

The exceptional performance of the S/850 originates from the precisely matched pairing of its active driver and passive radiator. The forward-firing 12-inch active driver uses a CarbonAlloy™ cone with a pure carbon fiber center cap, which REL fitted in place of the solid aluminum moldings of earlier models to reduce moving mass and stiffen the cone. This allows the driver to accelerate and decelerate with remarkable speed, faithfully tracking the complexities of the audio signal. Working in concert is a downward-firing 12-inch passive radiator with a flat primary piston of carbon, glass fiber and closed-cell foam, which REL says is 40% stiffer and lighter than before, with over 2.4 inches (60mm) of travel in each direction. This combination empowers the S/850 to produce profoundly deep and powerful low frequencies while crucially maintaining the speed and articulation necessary to integrate invisibly with high-performance main loudspeakers, thus creating a truly cohesive and full-range sound field.

Commanding Power: The Linear Class D Amplifier

Tasked with driving this driver system is REL’s Linear Class D amplifier, rated at 850 watts (RMS) of continuous output with a surge to 1,000 watts during demanding peaks. REL pairs a Class D output stage with a traditional power supply, and fits the input filters with the same thin-film capacitors used in its flagship designs. It delivers the instantaneous current required to manage the long excursions of the active driver with unwavering precision. This meticulous control results in bass that is not only deep and impactful but also astonishingly detailed, textured, and free from smearing or overhang. It reveals the subtle nuances hidden within the lowest musical octaves and the most complex cinematic sound effects.

Perfect Integration: High Level Input & PerfectFilter™

A hallmark of REL design is the High Level Input, and the S/850 employs it to perfection. By connecting directly to your main amplifier's speaker outputs, the S/850 receives the identical sonic signature (the same signal, including the amplifier's character) as your main speakers. This ensures close tonal consistency and perfect timing integration. REL’s proprietary PerfectFilter™ technology further refines this connection, specifically tailored to complement the sonic characteristics of modern, high-end loudspeakers. This results in a seamless blend, where the S/850 extends the bass response naturally, enhancing the overall soundstage width, depth, and openness without drawing attention to itself.

Building the Ultimate Bass Structure: Line Array Capability

While a single S/850 delivers truly reference-caliber performance, its design anticipates the pursuit of ultimate bass reproduction. The robust cabinet incorporates secure coupling hardware enabling vertical stacking, allowing the creation of Reference Line Arrays of up to three units per channel. This approach doesn't just increase output; it multiplies the benefits of speed, clarity, and effortlessness. A REL Line Array pressurizes the room more evenly, smooths out room modes, and delivers bass with enormous scale, dynamic impact, and lifelike presence, forming an unshakable sonic foundation for the most ambitious audio or home theatre systems.

Optional Wireless Freedom: Airship Direct Compatibility

For installations where running cables is impractical or undesirable, the S/850 offers seamless compatibility with REL's optional Airship Direct wireless system, whose receiver plugs straight into a dedicated port on the S/850’s amplifier panel with no extra cables or power supply. This system transmits both the High Level and .1/LFE signals wirelessly with zero compression, ensuring that the full fidelity and dynamic impact of the audio signal are delivered without compromise. Airship Direct provides the freedom to place the S/850 (or multiple units in an array) in the optimal room position for the best sonic performance, unconstrained by cable lengths.

The Listening Room Difference

We are a third-generation, family-owned hi-fi shop in Chestertown, Maryland, known for service and trust rather than hype. Every system begins with a conversation about your room, your music, and your goals, and the advice you receive comes directly from our owner, Mike Hoatson, and our small, dedicated team. We offer white-glove delivery, careful setup, and ongoing support so your system performs as it should. We do not just ship boxes, we build relationships that last well beyond the sale.

Specifications