REL Carbon Special Black Label

REVIEW
Chris Frankland
Feb 18, 2026

With 35 years’ experience, REL is the first brand most people think of when looking to add a subwoofer to their audio system. Earlier this year, I reviewed the excellent S/850 from their new Serie S, and when the opportunity arose to try the next model up the range, the editor didn’t have to ask me twice.

REL was founded by Richard Edmund Lord in Wales in 1990, because he was unhappy with the performance of the subwoofers of the day. Seeking someone who shared his ideals to take the company forward, he sold REL to John Hunter in 2005, who was the US distributor for Sumiko. Today, design is done in the USA and manufacturing takes place in China.

Black Label

The Carbon Special Black Label at £4,799 is one down from the top-of-the-range 212 Black Label at £5,499 and one up from the S/850 model (£3,599) I reviewed in Issue 249. Serie S sits below the Reference series and is intended for “higher-level systems in medium to large rooms”.

The Carbon Special Black Label has a larger cabinet than the S/850, measuring the same height and width but 25mm deeper front-to-back. Whereas the S/850 has a 12in carbon alloy active driver and a passive downward-firing ABR, the Carbon Special uses the same all-carbon 12in forward-facing driver as the No31 Reference model. REL had to design a passive ABR that was “capable of keeping up with” the main driver, so they chose the same all-carbon long-throw design used in the 212 Black Label.

Bigger built-in

The built-in Class D amplifier is also larger, rated at 900W, compared with the 850W of the S/850. However, it is said to be capable of 1,200W to 1,400W on peaks. All of REL’s subwoofers use analogue filtering, as they believe digital signal processing (DSP) is too slow. One of the key design criteria for REL is a fast response time.

A unique feature of REL subwoofers is the High Level connection protocol, invented by Richard Lord. Although you can connect a REL sub to the output of your preamp, amplifier or home cinema receiver, as you’d do with other subwoofers, REL recommend using their signature High Level connection.

The special 10-metre cable supplied runs from the loudspeaker terminals on the amplifier to the Neutrik Speakon socket on the back of the sub. REL say this ensures the sub is fed the exact same signal as the main speakers, which “builds forward the sonic signature of the main system”. REL point out that because the sub has a very high impedance, your amplifier will be unaffected and see zero drain. The only warning is not to connect the black ground wire to the black speaker terminal on Class D amps. I have used the High Level connection on several valve and transistor amps with no problems, and the sound is certainly better than using the low-level input to the sub.

Bass desires

Summing up what all of this means, REL’s UK sales director Rob Hunt said the Carbon Special “goes deeper, louder, faster”. But REL head honcho John Hunter, in one of his online videos, also hints at something that took me years to realise, namely that they “do far more than play loud and go deep, they let you see into the music”.

I could see how adding a sub to a pair of small speakers would give you more and better bass, but when I moved up to larger speakers, I thought, ‘I didn’t need more bass’. I had been missing the point.

After experimenting with several REL subs and speakers of various sizes, I discovered that it’s about far more than the bass. A REL sub cleans up the entire frequency spectrum and improves bass lines, vocals, drum kits and even cymbals, helping to reveal more inner detail in the music. REL’s John Hunter believes this is because all musical notes have a low-frequency component, and if you roll things off, say, at 40Hz, many fundamentals and all their harmonics are lost.

Let’s fire them up!

I listened to the Carbon Special Black Label in my home system, comprising an Audio Note TT3/PSU3 turntable with Arm Two and a Hana Umami Black cartridge, through the new Music First Audio LP103 LCR phono stage, a Viva Solista tube integrated amp, and Fyne Audio Vintage 10 speakers with SuperTrax super-tweeters. CD replay was via an Audio Note CDT Five transport and DAC Five Special. Mains blocks and cables were from MusicWorks.

I was lucky enough to have Rob Hunt set up the Carbon Special for me. He used his setup CD to adjust phase (0 or 180 degrees), crossover frequency and gain levels. REL advise placing a single sub in one of the room corners, but in my listening room this is impractical. We found that placing it just in front of the left-hand Vintage 10, close to the wall and slightly toed in, worked well. There is plenty of guidance on the REL website on placement and setup, but your retailer will usually do all of this for you and will have plenty of previous experience in achieving the best results.

Ace of bass

I was interested to find out how the Carbon Special would improve the Fyne Audio Vintage 10s, especially as they already have good bass extension.

The first surprise, as I found with the S/850, was that adding the Carbon Special tightened up bass lines and improved control. On ‘We’re In This Love Together’, the title track from Chris Walker’s Al Jarreau tribute album, the bass line was deeper, tighter and more agile, whereas without the sub it had been rather overblown. I could also follow the deepest notes better. Vocals were also improved – more open and ‘human’ – and Gerald Albright’s wonderful sax was better voiced, more articulate and expressive.

Moving on to ‘Omission’ from guitarist Julian Lage’s Speak To Me album, using the sub, I felt there was more definition and better note shape and leading edge on his acoustic guitar, while his electric guitar was cleaner and better voiced. The bass line was tighter and more fluid, and the drum kit crisper, cleaner and more dynamic. The track’s staccato rhythm was also better conveyed.

Switching to Discovery

Switching to the superbly recorded Discovery album by guitar legend Larry Carlton and the track ‘Minute by Minute,’ I was really impressed by how the Carbon Special gave real weight and movement to the gorgeously sinuous, driving bass line. When the bass guitar was joined by a kick drum, the impact and tightness were palpable. Carlton’s guitar was more open, and I could hear each note better, while the drums and percussion were more clearly defined, with finer detail, delicacy, and crack.

A current favourite album of mine is Stream by pianist/songwriter Fergus McCreadie. On the track ‘Sun Pillars’, the REL sub really helped focus the fast-moving fingers of David Bowden on double bass, lending them weight, solidity and speed, while McCreadie’s piano had good definition in all registers, with weight, great delicacy and detail. Stephen Henderson’s delicate drumming was also well captured, as was how he and Bowden worked together to drive the track rhythmically.

The REL also impressed me greatly on the track ‘Night & Day’ from Jon Allen’s superb Deep River album. His vocals were really opened up by the REL, with improved range, clarity and power. Drums and bass were also tighter and punchier, and the track’s distinctive rhythms were sharper and more compelling with the REL in circuit.

Not just about the bass

Ideal not just for those with smaller speakers seeking deeper, better bass, the Carbon Special will also work its magic with much larger speakers. It proved a worthwhile step up from the cheaper S/850, delivering tighter, deeper, faster bass lines while also improving subtle detail in guitars, keyboards, brass and drums and percussion. It conveys the deepest notes of a bass line better while also revealing subtleties of play on cymbals, hi-hat and brushed snare.

Adding the Carbon Special to the system creates more space around musicians, widens the soundstage, and lets the music breathe. Plus, it really gets your foot tapping along to the music. And all of this for less than £5,000. I highly recommend it.

Technical specifications

Type: Subwoofer with built-in amplifier
Driver complement: 12in long-throw all-carbon active driver with downward firing 12in flat-cone all-carbon passive ABR
Lower frequency response in room: -6dB at 19Hz
Input connectors: High Level: Neutrik Speakon. Low Level: RCA, LFE RCA
Output connectors: High Level: Neutrik Speakon. Low Level: RCA, LFE XLR
Gain control range: 80dB
Phase switch: 0 or 180 degrees
Amplifier: 900W linear Class D
Wireless capability: Airship Direct (sold separately)
Dimensions (HxWxD): 41 x 48.8 x 56.5cm
Weight: 44.5kg
Finish: Piano black lacquer with detachable wooden grille
Price: £4,799, €5,599, $4,999