REL No. 25
Our Reference subwoofers allow us the opportunity to pursue the perfect reproduction of sound, while letting nothing get in our way. Our designers and engineers can dream big and take huge leaps in innovation. The result is truly reference level subwoofers that can extend the soundstage of the most renowned speakers and systems, bringing incredible clarity to the mid-tones in perfect synchronicity.
No. 25 commemorates and celebrates our quarter century of building the finest sub bass systems, while pointing to the future and our next 25 years as it employs our most advanced design, engineering and craftsmanship.
Available on backorder
Beauty, Power & Speed
No. 25 combines the power of an ultra-reliable 1,000 watt amplifier, with a lightweight and perfectly balanced carbon fibre 15” driver. All this is controlled by our legendary filter sets and proprietary crossovers with 2 separate parametric equalizers permitting remarkably flat in-room response, while maintaining the speed and resolution for which modern RELs have become known.
We want our customers to enjoy all this performance without being limited to only a few room locations, so we built-in our legendary LongBow™ wireless receivers into every No. 25. This design utilizes zero compression, resulting in stunning dynamics and bass extension without being tethered to a cable, while delivering sound quality comparable to our competitor’s hardwired designs. It’s just another example of how we strive to offer complete and thoughtful solutions.
Clarity From Strength & Elegance
No. 25 marks a new standard in cabinet execution, both for its physical beauty and the manner in which it manages the critical backwave propagating from the rear surface of the massive 15″ carbon fibre piston at its heart. The shape of No. 25 is designed to disturb and cancel much of the incredible force created by the inward stroke as No. 25 reloads for your music or film’s next set of demands. It is necessary to keep this backwave as silent as possible, while allowing the driver to “breathe” without compressing dynamics. The curvilinear cabinet walls deflect, diffuse and dissipate these waves into smaller cross plane waves. Minimizing rear waves that eventually emerge as comb filtering — noise that cancels the primary bass — is what creates clear, purposeful bass that strides into a room with tremendous energy and clarity.
Comprised of 30mm thick (about 1 1/8″) Australian MDF, transected by hardwood spars that break up common mode resonances within the top surface of the cabinet and down its sidewalls, our bracing is not unlike the spars in a ship’s hull. Some may view this as excessive, but these are the lengths our design team goes to to deliver the finest subwoofer extant, fully fitting of the title No. 25.
Natural Floor to Ceiling Bass
When we experience bass in real time out in the world, it occurs with height to it. It strikes our sinuses, it kicks at our chest cavities, it rumbles along the floor conveying power authority and majesty. Our Reference Line Arrays permits bass to emerge more naturally, adding a height component in how it propagates throughout the room. The bottom unit reinforces the deepest overtones, creeping and rumbling across the floor to produce room shake. The middle location provides crisp attack and articulation of kick drums or any transient-based event. The unit imparts the flutter and shimmer of all manner of instruments floating in air. Making Reference Line Arrays the Holy Grail of the REL experience and is only available with our Reference products.
Since 90 percent of the energy produced by a system resides in the bass regions, Reference Line Arrays are the magic element missing from so many otherwise state of the art systems. This air, transparency and, of course, effortless power that Reference Line Arrays convey can’t be imagined, it can only be experienced in person.
Scalable Bass, From Whispers To Boom
It takes huge power to invest the No. 25 with the shattering dynamics of which it is capable. The rugged beast of a 1,000 watt NextGen3 amplifier that powers No. 25 has already proven itself in the field in one of our previous designs, making us comfortable with not only its startling sonic performance but also its reliability.
However, No. 25 is no mere exercise in excess, but rather a thorough exposition in the art of rendering sub bass, totally, completely and with great deftness in tonality, expression and dynamics. It is this ability to not merely play loud, but to bring to life the contrast between loud and soft passages that makes REL owners so passionate about our designs. After all, dynamics are not merely the ability to play loud, but to bring to life the contrast between loud and soft passages in music or film. Ultimately, this is what makes the No. 25 the addiction it quickly becomes.
A Carbon Fibre Core
No. 25 has a heart of pure carbon, as we opted for a cone material that is stronger than steel, yet incredibly light. Carefully woven from pure carbon fibre, No. 25’s 15” cone structure weighs 70% less than a 10” cone of just two years ago. This combination of incredibly light weight coupled to remarkable structural integrity is what gives No. 25 its combination of speed and power.
Yet another benefit of the weight reduction strategy we employ is that it permits near-perfect dynamic balancing of the driver, yielding ideal behavior throughout its incredible 4” of fore-and-aft stroke.
Fine Tuning In The Palm Of Your Hand
Begin your relationship with REL Reference by simply picking up the remote; feel its heft, how its rounded contours fit gently in the cup of your hand. This is a carefully wrought system improvement that encourages the sort of finely detailed decisions during set-up necessary to achieve the perfect balance to the ultimate system owner.
REL Reference models employ remote control in order to assist and increase ease of initial set-up. We do this knowing that once properly set, the owner will likely use it rarely during the remainder of their ownership experience as RELs truly can be set-up correctly to reproduce all forms of music and film without resorting to cheap parlor tricks like turning bass up for movies and down for music.
Closed box, front-firing driver
Active Driver Size & Material
15 in., 380mm long-throw, carbon fibre cone with inverted carbon fibre dust cap
Passive Radiator Size & Material
Low Frequency Extention
-6dB at 14 Hz
High Level Neutrik Speakon, Low Level stereo RCA, LFE RCA, LFE XLR, SMA for wireless antenna
High Level, LFE RCA, LFE XLR Daisy Chain Outputs
1,000 watts (RMS) Ultra High-Current Power Supply
NextGen3 Class D
Longbow (Optional), Zero Compression, Individual discrete D/A and A/D Encoders
Fully Electronic Set Safe
Mains Input Voltage
220-240 volts, 110-120 volts for certain markets
7 Amp semi delay 230 volts operation, 15 Amp semi delay 115 volts operation
W x H x D
29 x 21.3 x 30 in. (736.5 x 540 x 762 mm)
168 lbs. (76 kg)
Piano Black Lacquer, 12 coats
Yes (10 Meters Nominal)
In the interest of product development, REL Acoustics Limited reserve the right to vary these specifications without notice.