REL S/850 Subwoofer

REL S/850 Subwoofer

Includes 3-Year Manufacturer’s Warranty

What's in the box

• Serie S/850 Subwoofer

• 6' AC Power Cord

• 32' Neutrik Speakon cable

• Line Array Mounting Hardware

• Cloth Grille

• User Manual and Warranty Information

• *The Premium Wood Grille is NOT included in your subwoofer purchase but is available for purchase.

Stunning Design Meets Raw Power

S/850 stands as the benchmark of the Serie S line, with its design innovations shaping and elevating its three stablemates. Every improvement is sweeping and comprehensive, ensuring the entire Serie S family benefits from the advancements pioneered in the S/850.

The results are spectacular: it delivers incredible attack and output beyond even the former Carbon Special at the very limits of performance, yet with the precision, quietness, and clarity that produce true dynamic range. Lightning-fast transients, deep effortless bass, and tonal richness combine to deliver nuance that elevates both music andhome cinema

Designed to be Perfect

The S/850 cabinet is longer, lower, wider, and deeper—proportions that give it a naturally dynamic presence. Subtle design details refine its look and feel: clean creases that catch the light, warm silver-gold badges with a titanium-like finish, and stainless-steel handles recessed into graceful ellipses. Beneath each front rail, precision-milled billet cylinders provide exact leveling, while thick internal aluminium slabs secure the handles for safe stacking in Line Arrays. Designed to complement modern interiors, the S/850 also offers an optional Premium Wood Grille, adding warmth and individuality.

Driven to Perfection

The S/850 is the result of relentless refinement. This progress comes not only from exploring newer, finer materials, but also from the thousands of hours of critical listening our team undertakes each year—experience that transforms raw engineering into musical and theatrical performance of the highest order. With every detail carefully considered, the S/850 delivers a level of power, nuance, and scale that redefines what’s possible in its class.

S/850 drivers now feature lightweight pure carbon-fibre centre caps, replacing the solid aluminium mouldings of earlier models. These caps reduce moving mass while stiffening the cone, resulting in explosive dynamics and the ability to resolve the quietest passages with delicacy and nuance. Feather-light yet rigid, they extend performance at both extremes—a hallmark of REL design.

Passive Radiator

Supporting this advanced active driver is a newly engineered down-firing passive radiator. Purpose-built to handle the extreme throw distances produced by the S/850’s more powerful amplifier and driver system. Its flat, primary-piston surface—crafted from carbon, glass fibre, and light, stiff closed-cell foam, represents an evolution of prior designs but is now 40% stiffer and significantly lighter. With over 2.4" (60mm) of travel in each direction, it expands dynamics and low-frequency authority, unlocking the full scale and impact of the S/850.

Monoblock Slam, Class D Efficiency

The S/850’s amplifier delivers the slam of massive Class A/B monoblocks while harnessing the efficiency of a modern Class D output stage. Supported by a robust traditional power supply, it produces 850 watts of continuous output and can surge to 1,000 watts during demanding peaks, ensuring ample headroom for both music and theaterhome cinema. Upgraded input filters, equipped with the same thin-film capacitors used in our flagship designs, introduce a new level of transparency and refinement previously unheard of in this class. Together, these advancements create dramatic improvements in clarity, sound staging, and sheer authority - an amplifier that blends brute force with finesse to anchor the performance of the entire Serie S line.

Analogue Filtered to Perfection:

We choose analogue because it is the only way to achieve truly natural sound. All REL input filters are 100% analog—among the fastest ever offered in a subwoofer. At the core is our renowned High Level Input, which connects directly to the speaker outputs of your main amplifier. This doesn’t draw power; instead, it carries the full sonic signature of your system, allowing REL to blend seamlessly with your speakers—a quality reviewers have praised for decades.

For systems where high-level input isn’t possible, our low-level input uses the same analogue filter circuit, available via both RCA and XLR connections, to deliver the speed, naturalness, and integration REL is known for. And in home cinema or dual-use systems, REL uniquely allows High Level and .1/LFE to run together—so music benefits from natural integration, while movies deliver the full impact intended by the mix.