REL recently unveiled a completely revamped Serie S lineup, and these two models sit right at the heart of the range.
They’re designed to bring deep, musical, controlled bass — equally into high-end stereo and immersive home-theatre systems. What’s more, they’re built to integrate seamlessly with your main loudspeakers rather than just boom and boom.
The S/550 and S/850 are now on demonstastion at PJ HiFi, get in touch to book a slot to hear these amazing subwoofers.
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REL S/550: High-End Subwoofer in a More Accessible Package
If you’re looking for reference-grade bass without going to the largest footprint or budget, the S/550 is a compelling choice.
Key Features
•550-watt amplifier for the active driver.
•12-inch passive radiator (with a 10-inch active driver) delivering deep extension (–6 dB around 19 Hz) in many cases.
•Redesigned driver with CarbonAlloy™ cone / carbon-fibre cap, improved suspension/travel and lighter moving mass for faster, cleaner bass.
•High-level “speaker output” connectivity plus standard line or LFE inputs — making it versatile for stereo systems and home cinema.
•Optional premium wood grille for aesthetic flexibility.
•Wireless-ready via REL’s Airship Direct ecosystem (so you can keep cabling clean) in applicable markets.
What this means for your system
In a medium-sized room (think ~250-500 sq ft), the S/550 gives you the kind of bass you feel but that also vanishes when you’re engrossed in the performance. The fast transients keep pace with high-quality speakers, meaning the sub blends into the soundstage rather than standing out. One of the key design goals of the Serie S line is “bass that supports, rather than overwhelms”.
So when you’re playing music with delicate dynamic contrasts or a film sequence with sudden power, the S/550 handles both with grace.
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REL S/850: Elevating to Benchmark Bass Performance
For those who want more — more depth, more head-room, more authority — the S/850 is the flagship of the Serie S range and takes things to the next level.
Key Features
•850-watt Linear Class D amplifier, with huge head-room and refined control.
•12-inch CarbonAlloy™ active driver matched with a 12-inch passive radiator, –6 dB at around 19 Hz.
•Larger, wider and more robust cabinet than its sibling to enhance scale and presence; refined cosmetic/ergonomic design.
•Also wireless-ready (Airship Direct) for cleaner setups.
•Designed with stacking/line-arrays in mind (for ultra-large installations or serious systems).
What this means for your system
If your space is larger (say 300-700 sq ft or more), or you’re pairing with major floor-standing speakers and want full-range playback with bass to match, the S/850 delivers. The power and refinement here mean you’re not just getting depth, but control — the bass remains tight, fast and clean even under demanding passages. The goal is authority without sacrificing integration.
In short: this is bass for when you absolutely mean business.
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Why These Matter — What Sets Them Apart
Speed & Integration – Too often subs are “boomy” or delayed; these REL models emphasise transient response and seamless blending with your main speakers.
Musical-First Approach – Rather than just “more bass”, REL stresses bass that is musical — balanced tonal character, proper placement in the sound-stage, integration rather than distraction.
Flexibility & Future-Proofing – Whether you’re in stereo hi-fi or building a home-theatre bass foundation, the connectivity, wireless readiness and stacking support mean you’re covered.
Premium Build & Finish – High quality materials, finishes, cabinet design and engineering overhaul all feature in the latest generation.
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Who Should Go for Which Model?
•If your room is medium sized, your speakers are high-quality but not enormous, and you want a subwoofer that doesn’t call attention to itself but enhances everything, the S/550 is a smart, focused choice.
•If your room is large, your system demands more from the bass (or you just want “max effect” from your sub), then the S/850 is the benchmark-grade step up.
•If you might scale later (e.g., adding a second sub or stacking for a line array) the S/850 gives you more head-room for future growth.
•Both models reward thoughtful placement and integration — the best subs don’t dominate; they disappear.
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A Few Practical Tips Before You Install
•Use the High-Level input if you can: connecting to your main amp’s speaker outputs ensures the sub hears exactly what your speakers hear, supporting seamless integration.
•Placement matters: even great subs benefit from correct room position and calibration. REL provide helpful guides.
•Don’t just turn it up: the goal is cohesive bass, not spotlighting the sub. Adjust gain and crossover so the sub feels like it’s part of the whole.
•Try both wired and wireless (if applicable) setups: wireless gives flexibility, but you’ll want to confirm the link is solid and latency negligible, especially for high-end setups.
•For two-channel music systems, consider a stereo pair or even dual subs for improved bass uniformity across the room (REL support line‐array stacking).
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Final Thoughts
The REL S/550 and S/850 represent a serious leap forward for subwoofer design in high-end systems. They combine power, precision, integration and musicality in ways many subs simply don’t. Whether you’re building a refined stereo rig that needs bass with finesse, or a full-blown system where bass impact is everything, there’s a strong offering here.
If you’re ready to give your system that missing “foundation” — the kind of bass that supports, thrills and disappears into the performance — these RELs are worth serious consideration.