Carbon Special

Serie S


Carbon Special is a new limited availability model that combines our latest engineering with cutting edge components from our reference line, all housed in a moderately sized chassis. It features our third-generation carbon fibre 12” driver with a new, bespoke CSP passive driver that delivers 50% longer stroke, powered by our 1,000 watt amplifier, itself guided by our CS PerfectFilter™. An all new cabinet with highly polished metal and carbon fibre touches appears only in this model.

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Carbon Special

Reference Performance, Modest Size

Where previous special editions have used existing cabinets, drivers and filters, Carbon Special uses many elements developed solely for Carbon Special. We employed our newest BlackWidow 12”(350mm) carbon fibre driver, developed to deliver superior dynamic balance throughout the full range of its considerable 4”(100mm) of fore-and-aft stroke. It is better able to handle, smoothly and effortlessly, the massive power needed to deliver explosive dynamics. We mated it with our NextGen 5 1,000 watt amplifier which has proven to be both a sonic wonder and utterly reliable. Directing all this is a CS PerfectFilter, a custom-designed variant of our latest evolution of filters that improves both ends of the spectrum. It delivers airy, delicate highs with greater reach into the nether regions within a soundstage, as well as truer, more powerful ultra-low bass delivery. If it sounds too good to be true, it almost is.

We didn’t stop there. The cabinet extends deeper than previous mid-chassis designs to optimize performance for this new driver complement. And its looks are delivered in a refined, mature manner with subtle use of carbon fibre details sprinkled among chrome and polished stainless accents. We predict Carbon Special will become one of the highest demand ultra-high performance subwoofers of all time.


CS PerfectFilters

Elevating low bass performance and overall clarity

Perfect is not a word REL throws around lightly but these latest filters are so good they require its use. Our PerfectFilters elevate the low bass performance to a new standard for a mid-chassis design, while subtle tweaks to its upper range performance allow for an airier, more transparent soundstage and improved clarity throughout the entire system’s performance. It is impossible to overstate its benefit to a fine audio system and all benefits that accrue to its musical performance go on to expand its merits in power theatre. A true two-for-one upgrade.


Sound Beyond Its Size

Inspired by the G/1 MK II

The key to Carbon Special’s amazing performance is its new BlackWidow 12”(350mm) forward firing active driver. Carbon fibre grabs the headlines with its ultra-lightweight and tough, resilient nature. Carbon fibre, while light, has excellent self-quieting properties that allow for far greater dynamics because the driver itself is so quiet. This generation 3 version features a much larger surround to better allow the explosiveness needed to set itself apart from the pack.  The inner suspension was re-tuned to take advantage of this and the result, found only here and upcoming versions of the G-1 MK II is a 12” that hits like a heavyweight but reacts like a much smaller driver.


Now Hear This

NextGen5 1000W Digital Amplifier

Power matters, and especially when our CS PerfectFilter demands more from the driver, additional power is crucial. This is why we placed the heart of our flagship No.25 amplifier into Carbon Special. At 1,000 watts, it has the current reserves to easily keep up with the demands placed upon it by even the most rigorous user. Carbon Special is capable of startling the listener, used in dual duty for both theatre and music its merits are immediately obvious in music which can lull the theatre aficionado into complacency, only to be yanked out of any sense of normalcy when a huge, unexpected transient explodes without warning. Think Pierce Brosnan’s 007 using plastique at work here.


Totally Stacked Performance

The REL Line Array

REL’s signature gift to the art of sub bass performance is undoubtedly our Reference Line Arrays, wherein three units per side are stacked vertically. This arrangement was practically invented for subs with the deportment of Carbon Special. For those who always dreamed of owning a REL Reference Line Array but were denied it because of their size, your ship has arrived.


Without Wire’s Snarl

AirShip™ Wireless Connectivity

Carbon Special works brilliantly with AirShip™, our state of the art wireless that transports sound invisibly with none of the compromises of conventional wireless. Available optionally, and at reasonable expense with Carbon Special. While most wireless compresses horribly, Airship uses military grade 5.8Ghz wireless with zero compression to send signals so pure and fast they sonically outperform hardwired using anything but the best cables. Not having to see a snarl of cables tangling up in one’s grand salon is itself a reward for you having worked so hard.

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Customer Reviews

Based on 19 reviews
Great Experience, love the REL S/510

I have only had my REL subwoofer two weeks, but I am loving the sound of it and what it adds to the music and to home theatre. The direct buying experience was painless, it arrived in 5 days and set-up was simple. I am still tuning it into the room. but the buying experience could not have been easier. I am definitely a new REL fan .....It is definitely money well spent .....


I bought one from Up Scale audio; got it home; hooked it up....loved it....SO, i purchases a 2nd one from Up Scale....WOW, now I have my own bass section, or so it would seem. I am running all tube equipment (Prima Luna gear) and these two subs are augmenting my Klipsch Hersey 3's until i can get corner horns....but these subs add what i have been missing all my life.....just the right amount of bass.....i am not an audiophile nor do i have the greatest gear in the world....but I am sure I am getting $100K sound out of my $40K system....and the REL's bring it all home....these babies are not even broken in yet....hope to have them broke in so when i get the Khorns, my life long dream of having "the sytem" in my mind, done.....great investment.

Easy setup and clear upgrade

I purchased a single S/812 at the end of 2020, as suggested by the subwoofer finder/speaker pairing. It's a lovely-looking piece of kit that screams outstanding fit-and-finish. I love the high level input that ensures that the S/812 blends perfectly with my speakers since I use it mostly for music. I upgraded to the Bassline Blue cable, which brought a subtle yet noticeable improvement over the standard cable in terms of naturalness. Placement and gain/crossover tweaks took few weeks. Counterintuitively, the S/812 works better when placed on the inside of the right speaker, halfway between said speaker and my equipment rack, aimed at the listener/seat. I settled with the gain one click over 9 o'clock, and the crossover about one click over 10 o'clock. Yes, some tracks can use a higher crossover or gain, but this particular setup works across all tracks in a long listening session. I listen to a lot of music across various genres. The S/812 has added depth and scale to many tracks, with more texture on voices and the midrange in general. And of course, segments with very low range (organ, synth, various drums, electric bass or double-bass) have become much more impressive without sounding overblown. Interestingly, this applies to recordings that used to sound "thin" including few piano albums that now sound fuller (but again, not artificially so). Very pleased.

Sonic foundation

I purchased the REL S/510 to supplement my aging Martinlogin Sequel II, electrostatic speakers.
These speakers are hybrid with the Electrostatic panel and 10" woofer in each speaker.
The 10" woofers in my speakers failed to produce the deep base in my two channel system.
The REL Sub replaced an older 12" Sub that never seemed to integrate sonically into my system. I would often leave it turned off; it was a store demo and may have had issues I was unaware of.
Stereo is the primary purpose of the Subwoofer purchase, but I may tie it into my theater system at some point because the REL can manage multiple sources.
I purchased the Airship with my Sub as recommended.
My Sub is 15-20 ft away from the stereo rack, and Airplay removed the long cable.
I have two Monoblock Tube amplifiers that required connecting the Airplay/Sub directly to my pre-amp using RCA cables for the Left and Right channels. Because I use an older Stereo pre-amp with one set of outputs for amplification, I used "Y" splitters to make the connection.
The room is in a basement with carpet, multiple bookshelves, 8ft ceiling, ~25ft width, and a depth shorter than the width of about 15ft. The room dimensions resulted in a wider than usual separation between my speakers. Some would call it "Near Field" listening.
The room is not a true rectangle; it has an alcove to the listener's left. The alcove creates a hole in the sonics that is compensated through speaker placement as much as possible.
Another essential detail of the room is that it is a multi-use family room; this also means I am limited, in speaker placement, including the Sub. All require the wife's seal of approval.
I listen to a variety of music: Jazz, Rock, Classical, & Pop:
Initial listening out of the box, immediately the sound stage become more crystallized, instruments found their place. This was before making any effort to optimize the sub location. The REL simply replaced the old Sub on the floor. The pluck of a Bass was better defined, less muffled; the drums crisper with a greater sense of impact. Notes meant to linger – seamed to lingered longer; those intended to be short and abrupt are quicker.

I've been listening to the new Sub for about 3 weeks now. The first week was time spent mostly attempting to get it placed as best I could in the room. I followed the instructional videos and tried my best to find the best spot. Because of the limitations of where I could place the Sub, it wasn't until the 2nd week I decided to make up for any lack of "synergy" with the room and my system by relying more on the Volume & Crossover adjustments on the Sub. I spent the 2nd week working on these adjustments.
I'm now at the end of my 3rd week. Last night, I discovered I had left my system on overnight, and this may have completed any burn in (with no music playing?). Maybe there is yet another level of burn in to complete; I don't know?
But, the music last night was sonically smoother, more energetic, alive more captivating. My system had a defined sound stage before; the REL fine tuned it, brought it into focus. It was like when the optometrist reaches the last series of lens flips, "which is better, this or this." The last "This" was differently better, way better than my old Sub, and clearer than it had been just a few days before.
I can read the sound stage without squinting. Each instrument/vocal has its location on the stage. No pointing and saying the drums are in that area, Now the drums are there with a firm finger point.
Subtle echoes in the recording are more obvious; the interaction between the instruments and their environment resonate, making the environment of the recording a more significant part of the listening experience.

It's hard to describe; my system was not horrible before, and I know the improvement I hear in my system is just that, an improvement to my system.

Audio is very subjective, with many variables related to equipment, rooms, and listener.
We audiophiles have an inadequate vocabulary to describe what we hear or feel. Such as "Crystal," what does that mean. I know what I'm trying to describe, but the reader may have a completely different interpretation. What I hear and feel is my experience, and I find it very hard to explain to another person.

I have a theory now. The Sub's frequency is the platform for all of the other notes to adhere. The old saying, "if the foundation of a build is poor, there is nothing you can do to prevent the building from having a structural problem." I believe my old Sub had issues; therefore, the rest of the notes suffered as well. Not that my system was terrible before my REL, but it has dramatically improved my listening experience. The solid bass frequency of the REL is the foundation of the rest of my system's sonic performance.


The S-812 has an excellent quality, after breaking in as recommended on the web-site.
The only complain I would have is the following:

I understand and agree that Rel builds very high quality sub-woofers. I watched many video from John Hunter and do trust his engineering and expertise. Very impressive guy!!!

However, as far as packaging, there should be more dedicated engineering on this aspect, PLEASE COMMUNICATE THIS EMAIL TO MR HUNTER...
Packaging seems weak and not be adequate for such units. I own several McIntosh equipment and was impressed with their packaging…

After the package was delivered and left at my door (too late to complain), I found after unpacking that one of the vertical side edges got busted (by some lift?). The cardboard had a large cut on each vertical side for about 4 or 5 inches.
It seems that the vertical side edges are not protected at all. The top and bottom were indeed solid, vertical side edges had no protection. See attached picture.

Some to think in the future with your development Team and Mr. Hunter. It is unfortunate for me, such a beautiful unit. And… this was my second unit ordered this month.

Carbon Special

Suggested Retail: $3,999

Carbon Special is a new limited availability model that combines our latest engineering with cutting edge components from our reference line, all housed in a moderately sized chassis. It features our third-generation carbon fibre 12” driver with a new, bespoke CSP passive driver that delivers 50% longer stroke, powered by our 1,000 watt amplifier, itself guided by our CS PerfectFilter™. An all new cabinet with highly polished metal and carbon fibre touches appears only in this model.



Front-firing active driver, down-firing passive

Active Driver Size & Material

12 in., 300mm long-throw, carbon fibre cone with inverted carbon fibre centre cap

Passive Radiator Size & Material

12 in., 300mm Carbon, carbon flat cone structure, steel chassis

Low Frequency Extention

-6 dB at 19Hz (in Room)

Input Connectors

High Level Neutrik Speakon, Low Level stereo RCA, LFE RCA, and LFE XLR

Output Connectors

High Level Neutrik Speakon, LFE RCA, and LFE XLR

Power Output

1000 watts (RMS)

Amplifier Type

NextGen5 Class D

Wireless Capability

Airship Wireless Required (sold separately)

Protection System

Fully Electronic Set Safe


D.C. Fault


Output Short


Mains Input Voltage

220-240 volts, 110-120 volts for certain markets


5 Amp 220 volts operation, 9 Amp 120 volts operation


W x H x D

17 x 18 x 21.25 in. (430 x 455 x 539 mm)

Net Weight

85.3 lbs. (38.7 kg)


Piano Black Lacquer, 8 coats

Supplied Accessories

Mains Lead


Neutrik Speakon

Yes (10 Meters Nominal)


Users Manual


In the interest of product development, REL Acoustics Limited reserve the right to vary these specifications without notice.