REL S/550 Subwoofer – Precision Design, Powerful Bass & Seamless Integration

Designed for Excellence

The REL S/550 subwoofer is engineered with meticulous attention to both aesthetics and performance. Horizontal strakes carved into the side walls create a striking visual flow, while elegant elliptical returns cradle the handles finished in a warm golden-silver tone inspired by raw titanium.

Every detail has been refined to deliver a cabinet that is larger in internal volume yet visually lighter. The S/550 is lower, wider, and deeper than previous models, providing improved acoustic performance without overwhelming your listening space.

This additional cabinet volume allows the drivers greater freedom of movement and improves amplifier efficiency. At the same time, upgraded internal bracing ensures cabinet resonances remain tightly controlled for cleaner, more accurate bass reproduction.

Subtle refinements elevate the design even further:

• Discreet badges that blend into the grille cloth

• Silver accents integrated seamlessly into the cabinet surface

• Model numbers etched into the front rails, visible only when used in a REL Line Array system

An optional Premium Wood Grille introduces warmth and individuality, while front-rail levelling adjusters make installation effortless, even on uneven floors. These thoughtful details embody REL’s philosophy: great design balances usability, beauty, and performance.

Faster, Stronger Bass Performance

At the heart of the S/550 is the newly redesigned 10-inch high-amplitude driver. Nearly every component has been rebuilt, with only the original cast frame retained.

Key innovations include:

• CarbonAlloy™ cone construction for improved rigidity and speed

• Pure carbon fibre centre cap for sharper attack and smoother decay

• Redesigned suspension for greater driver travel

The result is a driver that feels effortless, responsive, and incredibly dynamic. Because the cone is lighter, the amplifier operates more efficiently while delivering greater output. This allows the driver to move further and play louder, producing bass that is both deep and incredibly controlled.

Advanced Passive Radiator Technology

Supporting the active driver is a newly engineered down-firing passive radiator designed to handle the extreme throw distances generated by the S/550’s powerful amplifier.

Constructed from an advanced composite of:

• Carbon fibre

• Glass fibre

• Closed-cell foam

the radiator is 40% stiffer and significantly lighter than previous versions.

With more than 60 mm (2.4 inches) of travel in each direction, this passive radiator enhances:

• Low-frequency extension

• Dynamic impact

• Overall bass authority

Together with the active driver, it forms a system capable of remarkable depth and power within a compact footprint.

550-Watt Pure Class D Amplifier

The 550-watt Pure Class D amplifier powering the REL S/550 delivers exceptional performance well beyond its rated output.

Laboratory testing confirms:

• 600 watts of continuous power for extended periods

• 50% higher crest power compared to the previous generation

This robust amplifier produces the fast, deep bass response that the REL Serie S range is famous for.

High-quality polypropylene capacitors, similar to those used in REL’s flagship Reference models, enhance the input filters and contribute to:

• A wider soundstage

• Greater transparency

• Improved clarity

Combined with REL’s second-generation PerfectFilter™, the S/550 produces astonishingly deep bass from a remarkably compact enclosure.

Precision Analog Filtering for Natural Sound

REL believes that analogue filtering delivers the most natural and musical bass performance. That is why every input filter in the S/550 remains 100% analogue.

At the centre of the design is REL’s renowned High Level Input, which connects directly to your amplifier’s speaker outputs. Rather than drawing power, this connection captures the complete sonic character of your system, allowing the subwoofer to blend seamlessly with your main speakers.

For systems where High Level connections are not possible, the S/550 also includes:

• RCA low-level inputs

• Balanced XLR inputs

Both utilise the same high-speed analogue filter circuit, ensuring the same level of precision, speed, and natural integration.

For home theatre setups, REL uniquely allows High Level and .1/LFE inputs to operate simultaneously, delivering perfect musical integration for stereo listening while preserving the full cinematic impact for movies.

Expandable Serie S Line Array

REL’s Serie S Line Array system is designed for enthusiasts seeking reference-level performance. Starting with a stereo pair of subwoofers, the system can expand progressively to three units per channel.

This scalable configuration produces:

• Exceptional soundstage height

• Greater dynamic range

• Immersive floor-to-ceiling bass energy

The S/550 introduces a precision-milled knurled aluminium adjustment knob integrated into the body rails. This mechanism allows the bottom unit in a Line Array to be perfectly levelled on uneven flooring such as thick carpets or dual-pad installations, ensuring stability and optimal acoustic performance.

Airship Direct™ Wireless Connectivity

In high-end audio systems, cables are often unavoidable—but sometimes they are inconvenient or impractical. REL solves this challenge with Airship Direct™, an optional wireless transmission system.

Airship Direct™ sends wide-bandwidth compound signals, simultaneously transmitting:

• High Level signals

• .1/LFE signals

Even with the power and scale of the S/550, this wireless solution maintains REL’s signature speed, transparency, and bass authority.