User Manual

Thank you for purchasing your new REL No.25, this unit is produced with great pride and operates as the

standard bearer summarizing a journey that has taken REL 25 years to achieve. As the commemorave

unit marking 25 successful years, the No.25 takes all the best technologies developed over the past quarter

century and adds a few important design improvements to create a new standard to carry us on to the

next 25 years.

Scale and Power: There is, as the saying goes, no replacement for displacement. Our development of a

super, light, fast 15 inch driver was no easy task and it took quite some me to nd a manufacturer capable

of building to our standard. Anyone can build a big, loud 15 inch driver; the hard part lies in keeping it

lightweight and yet s enough to hold up to the rigors our customers regularly put their units through.

160 square inches, capable of moving 2” fore and a (total stroke of 100mm or approx. 4”) of specially

prepared, woven carbon bre allows for massive wave-fronts to be developed. And yet, what will surprise

serious students of the infra bass art is the speed, texture and liquidity this driver expresses. But for the

eortless extension and power it produces in spades, it sounds even faster than a great 10” driver.

Un-corrupble Power: REL required serious power to unlock the performance potenal of the No.25 driver

and so we turned to our newest amplier design, a specially developed Class D amplier that produces a

connuous 1,000 was and can deliver yet higher output on peaks. Naturally, this amplier has already

proven itself to be rugged and reliable in the eld so feel comfortable trusng our commemorave design

to this beast of an amp.

It All Begins Up Front: To this bulletproof amplier and driver combinaon, we applied the legendary lter

set we developed for the No.25; these are the fastest lters we have ever measured at just 4 ms and a

crossover that begins as low as 20Hz. Beyond simply technical bragging rights, they are the most natural

sounding lters we have ever experienced.

Taming the Room: We don’t believe in room correcon, too oen this is the bason of those who would

rather not get it right in room design nor set-up, but believe they can “correct” it all with an enormously

complicated lter called room correcon. There is no free lunch in high end audio and the price that must

be paid is loss of impulse response (speed and dynamics)—not to menon highly variable results using

these computerized aempts to x all.

We have chosen to include not 1 but 2 parametric equalizers using specially developed REL-fast lters. Each

lter permits boost or cut of 6 dB, a perceived doubling or halving of output in a narrow frequency range.

REL Parity™ allows the advanced set-up arst the ability to idenfy room modes, both peaks and dips, and

Dear No.25 Owner