REL S/850 Subwoofer

REL S/850 Subwoofer with 12” Active Driver and 12” Passive Radiator

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 and theatre. For those seeking a more bespoke finish, an optional Premium Wood Grille upgrade is available for added warmth and individuality.

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.

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.

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 theatre. Upgraded input filters, equipped with the same thin-film capacitors used in REL’s 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

REL choose analogue because it is the only way to achieve truly natural sound. All REL input filters are 100% analogue - among the fastest ever offered in a subwoofer. At the core is REL’s 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 isn’t possible, the 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 theatre 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.

Serie S Line Array

REL Line Arrays are renowned for their sound staging and dynamics - performance that continues to set the standard in the high-end audio community. Like all REL Line Arrays, they’re designed to grow with the listener: start with a stereo pair, expand to four, and ultimately rise to six units for true floor-to-ceiling authority. Precision mechanical couplers tie each upper unit securely to the anchor REL on the floor, ensuring both stability and seamless performance.

The S/550 serves as the gateway into this world, offering a scalable path into Line Array performance. Stepping up, the S/850 brings greater scale, weight, and authority - proven at international shows to elevate finely matched systems. The effect is transformative: vocals gain striking presence, instruments bloom with natural dimension, and cinematic effects explode with realism. A true state-of-the-art experience, made both scalable and accessible.

Wired For Sound… Wirelessly

Sometimes the best wire is no wire. Quality cables are a given in high-end audio systems, but there are occasions where it is impractical, unsafe, or unsightly to drape a cable across the room. REL delivers the ultimate solution with Airship Direct™, their optional wireless system that transmits wide-bandwidth, compound signals, carrying both High Level and .1/LFE simultaneously. Even with the scale and output of S/850, Airship Direct™ preserves the speed, transparency, and authority that define REL. It allows seamless transitions between music and movies without ever touching the controls, all from a single module that plugs neatly into the rear panel and stays invisible in your room. Simple, direct, uncompromised: Airship Direct™.

Our Review

The REL S/850 is the crown jewel of the Serie S line, bringing together cutting-edge engineering and years of fine-tuning to create a subwoofer that feels as refined as it is powerful. With lightning-fast transients, deep effortless bass, and a tonal richness that breathes life into both music and movies, it delivers an experience that’s as much about finesse as it is about raw output. Its cabinet design not only looks stunning with clean lines and thoughtful detailing but also contributes to its naturally dynamic presence. Inside, the pure carbon-fibre driver caps, analogue input filters, and a mighty 850 Watt amplifier (capable of surging to 1,000 Watts) work in harmony to produce explosive dynamics and delicate nuance in equal measure. Whether used solo or as part of a Line Array, the S/850 redefines what’s possible from a high-performance subwoofer, wrapping power, precision, and style into one unforgettable package.