REL Acoustics S/550 Subwoofer

Engineered and Designed for Excellence

The S/550's design is a study in purposeful detail. Its visually lighter cabinet is carved with horizontal strakes and features elegant elliptical handles finished in warm golden-silver, echoing raw titanium. This new generation achieves the seemingly impossible: a physically larger cabinet (lower, wider, and deeper) that looks lighter than its predecessor. The increased internal volume gives the driver greater freedom and improves amplifier efficiency, while updated internal bracing keeps cabinet resonance firmly under control. Subtle touches like concealed badges, quiet silver accents, and model numbers etched into the front rails (visible only in a Line Array stack) complete the refined look. For a bespoke look, an optional Premium Wood Grille is available, and front-rail leveling adjusters ensure effortless setup, even on uneven floors. This attention to detail reflects REL’s philosophy: great design balances thoughtful usability with beauty and performance.

Drive Faster. Drive Better.

The S/550 features a completely rebuilt 10” high-amplitude driver—only the cast frame remains the same. Its advanced CarbonAlloy™ cone, capped with pure carbon fiber, sharpens the attack and smooths the decay, allowing notes to fade naturally. A redesigned suspension provides greater travel to easily handle the amplifier's increased power. In practice, the driver feels effortless and free from strain. Because it’s lighter, the amplifier works less while delivering more power, allowing the driver to move further and play louder than ever before. The result is a revelation in supple, dynamic performance.

Amplified Excellence

The Pure Class D amplifier is rated at 550 watts, but its performance goes beyond the numbers. In the lab, this rugged unit delivers a sustained 600 watts continuous with no strain. Its crest power is 50% greater than its predecessor, producing the fast, truly deep bass the Serie S is known for. By incorporating premium polypropylene capacitors (like those used in our Reference models) into the input filters, we've achieved a more open soundstage with greater transparency. As always, the unit is fed by our second-generation PerfectFilter™, ensuring utterly remarkable deep bass from a tidy footprint.

Analog Filtered to Perfection

REL exclusively uses 100% analog input filters—among the fastest available in any subwoofer—because it is the only way to achieve truly natural sound. The High Level Input connects directly to your main amplifier’s speaker terminals. It doesn't draw power; instead, it captures your system's full sonic signature, allowing the REL to blend seamlessly with your main speakers—a quality praised by reviewers for decades. For systems where the High Level connection isn't possible, the Low Level Input uses the same analog filter circuit, available via both RCA and XLR connections, to maintain REL's signature speed and natural integration. For dual-use systems, REL uniquely allows both High Level (for music) and .1/LFE (for movies) to run simultaneously, ensuring natural integration for music and the full theatrical impact for film.

The Scalable Serie S Line Array

REL Line Arrays are celebrated for their unmatched sound staging and dynamics. The S/550 is the ideal starting point for this vertical bass architecture, delivering the speed, nuance, and scale that define the performance. The system is designed to grow with you: start with a stereo pair, expand to four, or build a full six-unit stack for floor-to-ceiling authority. Precision mechanical couplers ensure stability and seamless integration between units. As the system grows, the S/550 reveals greater depth and dimensionality—enhancing vocals, adding realism to instruments, and delivering cinematic effects with powerful impact.

Wired For Sound... Wirelessly

For situations where running cables is impractical, the optional Airship Direct™ provides the ultimate wireless solution. This system transmits wide-bandwidth, compound signals, carrying both High Level and .1/LFE simultaneously. Airship Direct™ preserves the speed, transparency, and authority of the S/550, allowing seamless transitions between music and movies without ever touching the controls. It's a simple, direct, and uncompromised way to get the full REL experience.

We endeavour to despatch same day for orders placed up to 1pm on available stock items (items with stock message "Usually dispatched within 24 hours"). Please remember to check with us first for a physical stock check if next day delivery is important to you. Any items with stock message "Usually dispatched within 72 hours" are items that we do not hold in stock but order in from the importer or manufacturer as soon as a customer order is received. Occasionally these may be delayed beyond 72 hours due to importer/manufacturer stock levels but we will inform you as soon as we can if this is the case.

UK Orders

We despatch the bulk of our UK mainland items on a 24 hour service – Free of Charge.  Non Mainland locations - Isle of Man, Isle of Wight, the Scilly Isles, the Scottish highlands and Islands, the Channel Islands and Northern Ireland may take a day or so longer and are not Free of Charge. Smaller items are delivered using Royal Mail 24 or special delivery. Larger items are delivered using a courier service such as DPD or UPS.

International Orders:

Due to the nature of our products and brand restrictions we are only able to send certain items internationally. Smaller items are delivered using Royal Mail Small Packets Airmail with International Tracked and/or Signed depending on value of item and availability of the service. Larger International shipments are sent by insured and tracked services using UPS. If there are any delays due to specific customs regulations, etc, you will be contacted by Hifisound or by the courier with a request for any further information required. Customs duties can apply for shipments to any countries outside of the UK depending on where the product you have bought is made. Customers are responsible for all taxes and duties incurred when the items enter their country.

Collect in Store or Home Install

At the request of the manufacturer some items cannot be supplied by mail order but you can click and buy them and then elect to collect them from our store or arrange a home install (if applicable). Applicable items clearly state that they are Collect in store or home install. Once ordered you will receive a message prompting you to contact us by phone or email to arrange for us to deliver and install or to reserve and collect from our store at your convenience, you will also be advised of the delivery time / stock availability as not all Home install / collect in store items are held in stock.