Rel Acoustics No.31 Subwoofer 900 W black lacquered - Reference

The No.31 is nothing less than a pure reference model, carved from the flanks of the remarkable No.32, but using a newly developed 12" (350mm) all-carbon fibre driver. Every aspect of the No.31 has been vastly improved and refined over its predecessor. The No.31 features the classic reference filter used in the No.32, the same dual parametric filters, a driver that handles three times the power to deliver a truly thrilling experience.

SPECIFICATIONS

Type Front-firing closed-box driver

Active driver dimensions and materials 12" (300mm) long-throw carbon fibre cone with inverted carbon fibre centre cap, die-cast alloy chassis

Passive radiator dimensions and materials N/A

Low frequency extension 17Hz @ -6Hz dB

Input Connectors Neutrik Speakon High Level, (2) RCA Low Level, (1) LFE RCA, (1) LFE XLR

Output Connectors Neutrik Speakon High Level, (1) RCA Low Level, (1) LFE XLR, (1) Line XLR

Output Power 900 watts (RMS)

Amplifier Type NextGen 7 Class D

Wireless Capability REL AirShip II (sold separately)

Dual Parametric Filter YES

Protection System

Fully Electronic Safe YES

DC Fail YES

Short Output YES

Mains Input Voltage 220-240 volts, 110-120 volts for some markets

Fuses 7 Amp semi-delay 230 volt operation, 15 Amp semi-delay 115 volt operation

Dimensions W x H x D 25 1/8 x 17 x 28 1/2 inches (638 x 435 x 720 mm)

Net Weight 114.5 lbs (52 kg), Shipping Weight - 156 lbs (71 kg)

Finish Piano Black Lacquer, 12 ply

Accessories Supplied

Power Cord YES

Neutrik Speakon Cable Yes (10 meters nominal)

Owner's Manual YES

Repeatedly Perfect

The No.31 mirrors the No.32 design shot for shot, yet somehow manages to appear slimmer, crouching closer to the floor, almost feline in its grace. The elegant plated handles set in an ellipse have been retained, as has the string grille that allows large amounts of air to blast into the room without creating noise the way fabric grilles can. The No.31 features the curved radius of its sidewalls that defines both its performance and character. But the reduction in visual and actual three-dimensional physical mass is remarkable. No.31: when the best has to be delivered in a smaller space.

Line up for battle

The No.31 enables the same vertically stacked line array as the definitive No.32. It delivers a transformative performance that no competitor has been able to match. For those who have sought the ultimate musical and theatrical experience, Line Arrays unlock the final dimension of system reproduction. Audiophiles have chased three-dimensional sound for years, but they've missed the simple fact that height, not depth, of the image is the missing link. By creating products designed to be stacked 3 (or in exceptionally tall rooms, 5) units high while maintaining individual crossover and gain control for each subwoofer in the array, REL has created a masterpiece that finally delivers what serious audiophiles have been chasing for the past 40 years.

Amplified Perfection

The No.32’s 1,000-watt NextGen 7 Class D amplifier is also present inside the No.31, limited to just 900 watts to ensure the perfect complement to the No.31’s 12” bass engine. This allows for maximum dynamics while ensuring a long, merry life for both components. Again, part of the magic is the LimitLess Limiter™, which allows the amplifier to tiptoe right to the limit without audible compression, and which delivers an effortlessly rhythmic quality. Additionally, its dual parametric filters allow for precise micro-tuning; The deepest bass is slightly reinforced, while the upper bass ranges can be gently cut to ensure a brilliantly rendered transition from the bass to the main speaker. The electronic design of the Reference range is a work of art in itself.

Drive this

The incredible excursion of the 12" pure carbon fibre driver allows it to play as loud as its larger stablemate. However, the No.31 has the tactility, agility and attack that only the largest subwoofers have ever been able to offer. Furthermore, its sonic signature works in modestly sized rooms and with a wide range of quality speakers. The driver is accelerated by a specially wound 3" voice coil, driven by a 13-pound magnetic structure; even near its limits, the voice coil remains firmly within the space. It is this visceral power, combined with great delicacy and nuance, that is the signature of the No.31.

Total Control

Take control of your No.31 by picking up the REL Reference remote control. Immediately, you’ll be struck by the perfect fit in the palm of your hand, the result of careful thought and many generations of trial and error during prototype development. The second reaction is the awareness of its mass, which conveys its quality, permanence and immutability. It tells you: “I am a thing of substance, of quality. Pay attention, what you do next matters.” If you’ve owned a REL before (and 90% of Rel Reference owners have), all the familiar controls are within easy reach, exactly where you want them. The high level gain (or low if using active speakers) is conveniently located on the right side, the crossover is in the center, and the .1/LFE gain is offset to the left.

Below are three lovely metal toggle switches that handle the critical setup functions. The remote control on/off switch is on the bottom. It is as hidden as possible and will stay on once powered up and in use during setup without accidentally being turned off. In the center is the phase control. This is only used initially to determine the correct phase of 0 or 180 degrees. Additionally, top access to the Dual Parametric EQ, marked A and B, allows for the flattest, deepest bass, and at the other end of the bass frequencies, fine-tuning of the crossover behavior. This provides the perfect blend of the subwoofer with the main speakers and any trace of rumble and resonance generated by the room can be delicately eliminated.

REL's Reference remote is like the perfect butler: always impeccable, indispensable when needed, but then put aside at a later stage, when additions or further improvements to the system further require its services.