REL Acoustics S/550

Overview

The REL Acoustics S/550 sits within REL's high performance S line, the range designed to deliver serious speed, extension and articulation for demanding two channel systems while remaining equally capable in home theater. At its heart is a forward-firing 10 inch active driver paired with a down-firing passive radiator, driven by a powerful Class D amplifier. That combination lets the S/550 move real air with control, filling in the octaves below your main speakers without ever calling attention to itself.

What defines every REL, including the S/550, is its signature high-level Speakon connection. A cable taken from your main amplifier's speaker terminals feeds the sub a full-range signal, so it follows the exact character and timing of that amplifier. The result is a subwoofer that integrates for music first, blending seamlessly rather than simply reproducing low frequency effects. A separate .1/LFE input handles home theater duties, and continuously variable crossover, gain and phase controls make setup precise in real rooms.

The S/550 is for the listener who wants faster, deeper, more effortless bass under a fine pair of standmounts or floorstanders, and who values music integration as much as cinematic impact. It supports REL wireless options such as the AirShip II for a clean, cable-free connection, and can be run in stereo pairs or stacked line arrays as systems grow.

Key Features

• Forward-firing 10 inch active long-throw driver for speed and articulation
• Down-firing passive radiator that extends low frequency reach with control
• High-power Class D amplifier for effortless dynamic swings
• Signature high-level Speakon connection that follows your main amplifier's character and timing
• Separate .1/LFE input for dedicated home theater use
• Continuously variable crossover, gain and phase controls for precise room integration
• Compatible with REL AirShip II wireless system for a clean, cable-free hookup
• Runs in stereo pairs or stacked line arrays for larger rooms and systems
• Part of the high performance S line, engineered for music-first blending

How the S/550 Compares

REL S/550 vs REL Acoustics S/850

The S/850 is the next model up in the same high performance S line, using larger driver and passive radiator area with more amplifier power for greater output and deeper reach. If your room is large or you demand more ultimate authority in the lowest octaves, the S/850 offers more. The S/550 delivers the same S line speed and music-first character in a more compact, room-friendly package. See the REL Acoustics S/850.

REL S/550 vs REL Acoustics T/9x

The T/9x sits in REL's music-focused T/x mid range with a 10 inch driver and passive radiator tuned for excellent blending in typical rooms. The S/550 steps up into the high performance S line, delivering greater speed, output and lower extension for more demanding speakers and larger spaces. Both share REL's high-level Speakon integration, so choose by scale and headroom. See the REL Acoustics T/9x.

REL S/550 vs REL Acoustics Classic 99

The Classic 99 is a vintage inspired 12 inch design that leans into a warm, characterful presentation and retro aesthetic. The S/550 pursues a more modern, high performance goal with faster transient response and lower reach. Pick the Classic 99 for its classic look and voicing, or the S/550 for cutting-edge S line articulation. See the REL Acoustics Classic 99.

Recommended System Pairings

A subwoofer augments an existing system, so these picks pair fine main speakers, an amplifier to drive them and a REL wireless kit or cable for a clean connection.

• Spendor Classic 4/5 This compact two way standmount is fast and refined but rolls off in the deep bass, exactly where the S/550 fills in with matching speed and no bloat.
• Klipsch Heresy IV The Heresy IV is a lively, efficient Heritage floorstander that benefits from added low end reach, and the S/550's high-level connection lets it follow the Heresy's dynamic character.
• Yamaha A-S1200 This integrated amplifier drives your mains with clean power and provides clear speaker terminals for REL's high-level Speakon feed, so the S/550 tracks its timing precisely.
• REL AirShip II Wireless The AirShip II gives the S/550 a clean, cable-free high performance connection, ideal when the sub sits away from the amplifier for best room placement.
• REL Bassline Blue High Level Cable This upgraded high-level Speakon cable refines the signal path from your amplifier to the S/550 for even tighter, more coherent integration.

Frequently Asked Questions

What is the REL S/550?
It is a high performance 10 inch active powered subwoofer from REL's S line, built around a forward-firing driver, a down-firing passive radiator and a Class D amplifier for fast, deep, music-first bass.

How does the REL high-level connection work?
A Speakon cable is taken from your main amplifier's speaker terminals and fed to the subwoofer. This lets the S/550 follow the exact character and timing of your amplifier, so it blends for music rather than just low frequency effects.

Can I use the S/550 for home theater?
Yes. A separate .1/LFE input handles dedicated home theater duties, so you can run the high-level connection for music and the LFE input for movies at the same time.

What size driver does the S/550 use?
It uses a 10 inch forward-firing active driver paired with a larger down-firing passive radiator that extends low frequency reach with control.

How low does the S/550 go?
It extends to roughly 21 Hz in-room, giving convincing depth under most main speakers.

How much amplifier power does it have?
The S/550 uses a high-power Class D amplifier rated around 500 watts, providing effortless dynamic headroom.

What controls does the S/550 offer?
It provides continuously variable crossover, level (gain) and phase controls, letting you dial in precise integration in your specific room.

Can the S/550 be used wirelessly?
Yes. It is compatible with REL's AirShip II wireless system for a clean, cable-free high performance connection between amplifier and subwoofer.

Can I run two S/550 subwoofers?
Yes. REL subwoofers are frequently run in stereo pairs or stacked line arrays to increase output, smooth room response and improve soundstage scale.

What speakers pair well with the S/550?
It complements standmounts and floorstanders alike. Options in our catalog include the Spendor Classic 4/5 and the Klipsch Heresy IV, both of which benefit from added low frequency reach.

Does the S/550 come with a high-level cable?
Yes. A high-level Speakon connection cable is included. You can upgrade to the REL Bassline Blue high level cable for further refinement.

How does the S/550 compare to the S/850?
The S/850 is the next model up in the same S line with larger driver area and more power for greater output and depth. The S/550 shares the same music-first character in a more compact form.

How does it differ from the T/9x?
The T/9x sits in the music-focused T/x mid range, while the S/550 is a high performance S line design offering more speed, output and lower extension for demanding systems.

What finishes are available?
The S/550 is typically offered in high gloss black and high gloss white.

Where should I place the S/550 in my room?
REL recommends starting in a corner and fine-tuning position, crossover, gain and phase by ear. Corner loading often yields the deepest, most even bass.

Is the S/550 suitable for small rooms?
Yes. Its compact cabinet and continuously variable controls let it integrate cleanly in small to medium rooms without overpowering them.

Do I need a special amplifier to use the high-level connection?
No. The high-level connection works with virtually any amplifier that has standard speaker terminals, including integrated amplifiers like the Yamaha A-S1200.

How heavy is the S/550?
It weighs approximately 46 pounds, making it manageable to position while remaining solidly built.

What warranty does the S/550 carry?
The S/550 is covered by REL Acoustics for 3 years parts and labor to the original owner when purchased from an authorized dealer.

Why buy from All Elite Audio?
All Elite Audio is an authorized REL Acoustics dealer, so your S/550 arrives with a full factory warranty and expert setup guidance. We help you match the right subwoofer to your speakers and room, and this model is in stock.