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REL Acoustics 212/SE Sub-Bass System

REL Acoustics 212/SE Sub-Bass System

In some ways I’m an unlikely choice to write  a subwoofer review. (REL calls them “sub-bass systems,” which is technically accurate, but for now I’ll use the more common term “subwoofer.”) I have always had full-range main loudspeakers, from Infinity RS-1bs to Magnepan 20s, 20.1s, and now 20.7s. The large Maggies had decent low bass in their earliest incarnations, but the latest 20.7s have truly outstanding bass punch and extension, particularly for a planar panel. I’ve tried various subwoofers with all of these speakers and found glimpses of nirvana, but never long-term heavenly bliss.

I’ve read a lot of subwoofer reviews, and I’m sure you have too. For my own purposes, I’m interested in a sub that can augment a full-range high-end music system. Smaller subs for satellites or small rooms may be marvelous, but they won’t do the job in my approximately 25′ x 14′ listening room. Nor will they do the job for the large-scale symphonic music of which I am fond—let alone the rock and electronic music I play frequently. A “typical” review of a modern subwoofer, designed for a large system, might say something along the lines that “now, finally, we have a subwoofer that will not only shake the rafters on movies, but will seamlessly integrate with your main speakers on all kinds of music.” Kind of like the “now, finally” reviews that for years claimed that such-and-such a solid-state amplifier has bridged the gap with tubes. I’m not going to address the solid-state versus tubes issue, mostly because I have not heard in my own system many of the newest solid-state electronics. But I still like tubes.

My own prior experience in the subwoofer world, both with my systems and the sound systems of friends, dealers, and manufacturers, has been that while many high-end subwoofers definitely enhance the movie-listening experience, they’re not all good when it comes to listening to music. I have had no desire to write another typical subwoofer review, mostly because I haven’t heard a sub that truly enhances music while being “invisible” at the same time; i.e., subs always call attention to themselves in some unwanted way or another.

But REL’s 212/SEs have motivated me to share my experience, mostly because they are not what I would call “typical” when it comes to reproducing the lowest frequencies. They certainly are not typical when it comes to the reproduction of music, which is my priority and hence the focus of this review. (This is not to say I have completely ignored home theater, for which see below.)

If one has a full-range system, why would he want to mess with subwoofers in the first place? After all, full-range speakers were designed to be “full-range,” and they were probably pretty expensive. The primary reason of course for subs is that much music contains low-bass information, and we should not be afraid to try to reproduce it. Even when the instruments being recorded do not contain low-bass fundamentals, the recording may contain valuable low-frequency information that conveys the size and space of the venue.

The reality for loudspeaker manufacturers is that it is really difficult (and very expensive) to do high-quality extended bass in a single-box loudspeaker. It can be done, and is being done, but more often than not even the best full-range loudspeaker doesn’t extend much below about 35Hz. I know a number of audiophiles who acknowledge their systems do not reproduce the lowest frequencies, but have nevertheless had such difficulty in trying to reproduce that part of the spectrum they’ve simply given up trying. They are content with a great midrange and fairly great midbass—or so they say. I acknowledge the difficulties they (and I) have faced, but as long as manufacturers such as REL and others continue the quest to perfect the reproduction of low bass, we should not give up on the reproduction of truly full-range music. We enjoy bass drums reverberating through concert halls, powerful kickdrums in jazz ensembles, and hard-charging bass guitars at rock concerts. There’s no reason (other than troublesome neighbors) why we shouldn’t try to achieve full-range music reproduction for ourselves.

I have already alluded to one of the other potential benefits of a good subwoofer. When set up correctly, the low-frequency reproduction can dramatically add to the scale and depth of the recording venue, assuming the recording has been made in real space and not solely at a mixing console. This is perhaps the main reason I have returned to trying subs from time to time; once you hear it, that sense of volume and space is hard to give up. Prior to the RELs I sometimes heard other benefits of subs, as well. With better ones, set up correctly (which usually means judiciously), I often heard significant improvement in the midrange and higher musical frequencies. Saxophones sounded fuller and more three-dimensional, massed strings sounded more “massed” and less wiry, and so on.

To put the performance of the 212/SEs into perspective, I offer a very brief history of my prior forays into the subwoofer world. As noted, music reproduction is my priority. But I also have a high-def projector and drop-down movie screen and I am able to use my main sound system for movies and TV. I first tried subwoofers with 18″ drivers. They were awesome for effects-laden films, but overall I found them just too slow and heavy for most kinds of music. I fiddled with their crossovers forever, to no avail. I next tried single-driver 15″ subs in sealed enclosures. All of these subs, of course, contained built-in amplification and crossover networks. The smaller 15″ subs still offered plenty of extension and impact in my room. They definitely sounded faster than the 18″ subs and integrated somewhat better with my full-range planars. In my room, they also reproduced the lowest frequencies with ease. But even though I was more enthusiastic about these subs, I still couldn’t find one setting where I could simply relax and enjoy whatever music I decided to play. The subs would always call attention to themselves on certain types of music. After another lengthy round of incessant fiddling with crossover points and level controls, it just became too difficult to achieve seamless integration on all types of music. Ultimately I didn’t keep any of these subs in my system. And in the last few years I thought I had found a reprieve from the subwoofer wars, because the newer Magnepan 20.7s produce truly deep and well-controlled bass in my room. I shuddered at the thought of trying to integrate a sub with the big Maggies.


Enter the REL 212/SEs. I was introduced to these speakers by the enthusiastic folks at the REL exhibit at CES a few seasons ago. I knew that REL subs have been held in high regard by audiophiles for many years. I also knew that REL had a reputation for designing “sub-bass systems,” in that they were intended to be used with truly full-range main loudspeakers and augment only the very lowest frequencies. Having visual memories of the large stately REL systems of the past, I was pleasantly surprised to see that new RELs were sleeker and much more modern in appearance than their forebears. The 212 also took me by surprise in that I didn’t know that REL was now using a configuration of multiple high-tech drivers in any of its subs. The owner of and chief designer for REL, John Hunter, told me that the 212s were designed to offer “the most” of everything that REL could offer in a single enclosure: the most drivers, the most power, and the highest output REL could put together in one small-footprint design. A few discussions with John made it crystal clear that he made seamless music reproduction an absolute priority for all REL subs.

Before I even heard them, the 212s offered a number of design features that appealed to me, at least in theory. In light of my prior experience that even a good 15″ bass driver was not quite fast enough to blend seamlessly with a planar loudspeaker, I was encouraged by the 212’s use of multiple 12″ drivers. The smaller driver would hopefully offer greater speed. The cabinet houses a Class D amplifier rated at a genuine 1000 watts of continuous power, which I thought could offer excellent control of the woofers. The driver cones are made of what REL calls “continuous cast alloy” and are capable of an astounding 2″ linear excursion. There’s a good reason the grilles are designed with a significant amount of space between themselves and the drivers.

The 212 cabinet is somewhat tall but does not take up much floor space given all the drivers and electronics housed within it. I think the vertical alignment makes a good match with taller main speakers, such as my planars. Hunter explained to me that after a lot of experimentation with placement of drivers, number of drivers, active versus passive drivers, REL settled on a configuration of two active drivers mounted on the front panel, facing forward, with a 12″ passive radiator mounted on the rear cabinet of the speaker to add space and dimension and yet another 12″ passive radiator mounted on the bottom panel of the speaker, facing the floor, to complete the quest for effortless bass. He wanted the output capability of the 212 to be essentially unlimited for almost all real-world applications. After having now lived with a pair of 212s for over a year, I can report that he has succeeded. I often play music loud, movies sometimes louder, and have never come remotely close to reaching the limits of the 212’s output capability.

I also found appealing the overall look of the 212 and its flexible control features. The 212 is finished in a gorgeous piano black that would do justice to the finest Steinway. The four metal feet have an understated elegance that add to the overall visual appeal of the speaker. All of the controls are mounted on the back panel.

Living by the motto that hope springs eternal, I decided at CES I should try the 212/SE in my system. I have always believed that a pair of subwoofers is easier to integrate than a single sub. A pair of subs would also allow for a greater and more even distribution of bass output throughout the room. John Hunter also believes in a stereo pair of sub-bass speakers. So we agreed that a pair of 212/SE’s would be delivered to my house within the next month or so.

The 212’s arrived in very sturdy packaging and in flawless condition. They are not difficult to move around, but I decided to wait for Hunter to install them and set them up. I am fortunate in this respect and I realize John can’t set up all of the speakers he sells. But the owner’s manual is comprehensive, and REL does offer on its website a very informative and useful set of videos explaining the setup and use of the 212s and its other subs.

Hunter ended up placing each of the subs a little to the inside of and slightly behind each of the 20.7s. He brought with him certain test CDs, and I simply watched as he did all the work, moving each REL a little this way and that, so that they did not end up completely symmetrical (but close). He also moved the 20.7s around until he found the best overall integration in the room. In light of the excellent bass extension of the 20.7s in my room, Hunter chose a very low crossover frequency for the 212s, at or near the lowest setting on the crossover control (approximate frequency of 25–30Hz). He didn’t want to double up with the 20.7s, but rather only go below the Maggies. (By the way, if you have never had John visit your house to set up speakers, you should do so. He is absolutely one of the best I have ever seen in the industry at speaker setup. He loves music and is great company as well.)

A few words are in order about the different ways in which the 212/SEs can be connected to your sound system. One of the special features offered by REL is the possibility of high-level connection of the sub to the amplifiers driving your main speakers. In essence several leads of the provided speaker cable are connected to the red terminal of the amplifier, and one lead to the black terminal. At the subwoofer end of the cable is a Neutrik Speakon connector that provides solid and secure plug-in to the sub. The benefit of this high-level connection is better integration of the REL with your main loudspeakers—both are driven by the main loudspeaker amplifier and wear the same sonic cloth of that amplifier. Your main amplifier doesn’t actually drive the RELs, because the sub contains its own 1000-watt amp. But your main amplifier is used to drive the internal REL amp, thereby imparting the overall sonic signature of your amp not only to the mains, but to the subs as well. REL strongly urges this method of connection, unless it is impractical for some reason. I believe this speaker-level connection is one of the secrets to the success of the RELs. It offers a level of seamlessness between the mains and the subs whereby speaker and sub truly sound like one extended loudspeaker, not two.


There are three other ways to connect the 212/SE to your music (and home-theater) system. First, there are RCA inputs on the back panel for connection to the audio outputs of your preamplifier. I have used this method and it works very well, but the sonic presentation is not quite as seamless as using the speaker-level inputs. There is also a .1/LFE RCA input on the back panel for connection to the LFE output of a home cinema processor. Interestingly, if you use the LFE input of the sub, REL recommends that you use it simultaneously with the high-level inputs (so long as your processor is set to “large” for the main speakers). In this manner the 212/SE essentially acts as two subs; one for the low frequencies contained in the normal left/right channels and one for the LFE effects channel.

Last, the 212/SE offers the possibility of wireless connection through REL’s proprietary “Longbow” technology. The Longbow transmitter (available separately) is said to provide wireless connectivity with no loss of signal and no compression. I have not tested the wireless capability of the 212/SE.

Controls are provided on the back panel of the 212/SE to allow integration with any main loudspeaker. There is a stepped level (volume) control and a stepped crossover control, covering the range from 30Hz to 120Hz. There is also a separate stepped volume control for the .1/LFE input. Toggle switches on the back of the speaker allow phase adjust, wireless on/off, and a standby position for the sub. There is also a true on/off switch on the rear panel.

I am not going to take time to discuss details of setup, particularly as I was fortunate enough to have John Hunter perform the job at my house. As noted, the owner’s manual and online videos are very helpful. But I will discuss how the 212/SEs work with, and not against, my Maggie 20.7s. For all testing purposes the 212s were connected to my amps through use of the high-level Neutrik connector. I was using VTL 750 amps when I started the audition, but last year switched to a review pair of new Audio Research 750SE monoblock amps, review forthcoming. My music auditioning commenced in a kind of reverse fashion for subwoofers. I kept the location, volume, and crossover settings dialed in by John Hunter. But instead of starting with sonic blockbusters, I started with simpler material that had highlighted the subwoofer problems I experienced in the past.

One of my favorite jazz LPs is Sonny Rollins and the Contemporary Leaders [OJC], featuring a great back-up band Rollins put together for this West Coast recording session in 1959. Like many OJCs, sound quality is excellent. On most of the cuts Rollins’ sax is in the room with you. One of the songs, the old standard “How High the Moon,” wasn’t planned for this session and almost wasn’t recorded. Rollins was jamming the tune with Barney Kessel on guitar and Leroy Vinnegar on bass, waiting for other band members Hampton Hawes and Shelly Manne to arrive at the session. Fortunately the recorders were on and captured the close-miked guitar, sax, and bass. Vinnegar has a great bass solo that has always posed problems for previous subwoofers in my system. Even when I set the crossovers to very low points, the upfront bass would become a little thick and plummy. With the subs turned off, no problems. If I turned the gain setting on the subs low enough to reduce most of the problems, the subs were of little use on most other musical material. It was an issue I couldn’t solve.

With the new REL 212/SEs in the system, and at the same settings established by John Hunter, I put the disc on my turntable and crossed my fingers. To say the least, I was very pleasantly surprised. Leroy Vinnegar’s bass was still in the room with me, but in no way was it heavier or slower than with the 20.7s used without subs. If anything, it sounded a little faster and tighter with the RELs in the system. A bigger surprise was the reproduction of the sax, which had always sounded rich and three-dimensional with the Maggies alone. To be sure of what I was hearing, I got up several times to turn the subs on and off while listening to many of the cuts. There was no mistaking that with the 212s active in the system, Rollins’ sax sounded even more three-dimensional and surrounded by more air than it did through the unaided 20.7s. I had caught glimpses of this effect with my prior subs, but with the 212s it sounded like I had made a major upgrade to my amplifiers.

Another jazz album that had presented subwoofer issues in the past is The Red Hot Ray Brown Trio [Groove Note]. With previous subs in the system, Ray Brown’s beautifully articulated bass on cuts such as “That’s All” tended to lean towards heaviness and sluggishness. But with the combination of 20.7s and 212/SE subs, Brown’s playing seemed even more sprightly than with the  Maggies alone and his double bass itself became more rounded and three-dimensional, without heaviness.

Thus encouraged by the performance of the RELs, I still wanted to make sure they were staying out of the way on musical material that didn’t feature subterranean bass. Norah Jones’ recent album, Day Breaks [Blue Note], is a jewel and perfect for this test. Her voice is pristine and the overall recording is of reference quality. Her back-up band (no credits given) is propelled by drums, stand-up bass, and bass guitar. I played the songs “Day Breaks,” “Sleeping Wild,” and “Fleurette Africaine,” first with the RELs switched off. They sounded great through the 20.7s alone. I then played the same cuts with the subs switched on. The songs still sounded beautiful—Norah’s voice was clear as a bell, kickdrum still tight, and stand-up bass very articulate. No downside that I could discern. But there was a surprising upside to using the RELs—Norah’s voice sounded more attached to a living body, there was more air around all of the instruments and even greater kick to the kickdrum. Again, it sounded as if there had been a major upgrade to my amplifiers or phono cartridge. Importantly, however, at no point did I ever get the sense that sound was coming directly from the RELs.


With the potential problem records out of the way, it was time to try my big-bass regulars and see what the 212s could do. Hopes were high and, not surprisingly, the RELs came through with flying colors. First up was the famous recording of Also Sprach Zarathustra [Decca], with Zubin Mehta conducting the L.A. Philharmonic at UCLA’s Royce Hall. (Fun fact, sort of: Stanley Kubrick originally commissioned famed movie composer Alex North to write the score for 2001: A Space Odyssey. North wrote a complete score with which he was very satisfied, but along the way Kubrick apparently decided that the older composers were better suited to his masterpiece, thereby making Richard Strauss a household name. Unfortunately Alex was not told of the change and was devastated when, at the world premiere of the film in NYC in 1968, he realized his score had been tossed.)

The opening low organ notes of “Sunrise” were extremely deep and well-defined by the RELs, allowing easy differentiation of separate notes that could easily have blended into one with lesser subs. Now we were in a sonic territory that the 20.7s hinted at but simply could not fully reproduce by themselves. The walls of my room expanded, the organ was felt (not just heard), with the floor and listening chair vibrating in unison. Also crystal clear, and powerful, were the opening stirrings of the basses and contrabassoon, leading to the dramatic introduction of the timpani. Now we’re talking! That drum has always been a showpiece on my system, but the 212s took it to a new level of lifelike impact and body. It blew me out of the chair, just like the guy in the old Maxell ad. I have been to the symphony (Disney Hall) three times in the last six weeks and this playback of Also Sprach was the closest I have yet come to achieving the impossible—lifelike reproduction of orchestral drums, organ, and double bass—in my listening room.

Another great recording by Zubin Mehta at Royce Hall, Mahler’s Symphony No. 3 [Super Analogue], serves to showcase the benefits of great low-bass reproduction. Double basses, bass drum, timpani, the hall…all were brought to life with the addition of the 212/SEs. There was absolutely a greater sense of space and volume, and the crescendos were more explosive than ever before. Yet again, never once did I get the sense of “Oh, listen to what the RELs can do.” It just seemed as if my 20.7s had grown an additional bass panel, or two (or three). I enjoyed this cohesiveness as much as, if not more than, the newfound bass extension.

By now I had a better handle on the capabilities of the 212s and wanted to see what they could do on rock and electronic music. Ludovic Navarre is a French composer that goes by the name of “St. Germain.” (A tip of the hat to Warren Gehl of Audio Research for turning me on to this guy.) His hypnotic music may be an acquired taste, but it grows on you (at least it grows on me). The St. Germain album Tourist [Parlophone] is a case in point—pulsing and exotic but not really in the techno genre. Bass lines and impact are killer, just what the RELs were designed to do.

The album Saudade [ESL] by Thievery Corporation is modern and fresh but could just as well have been a current project of Antonio Carlos Jobim—an homage to bossa nova and vintage movie soundtracks. The group used five female vocalists for this album, each one with a more beautiful voice than the next. I’ve heard it many times on my system and a few times on other systems as well. Once again the 212/SEs brought added life and realism to the recording: more air, more space around the singers and instruments, more body to the vocalists and other performers. The bass line on this album is not terribly extended, but that’s fine. The RELs did not add anything that wasn’t there to begin with.

I’m a late arrival to the ongoing recording party hosted by Bob Attiyeh and Yarlung Records. To quote TAS Publisher Jim Hannon: “Here’s a relatively new label dedicated to recording young and established concert artists with minimalist recording techniques using vacuum-tube microphones recorded directly to two-track.” Robert Harley has also enthused about this label. I was given a copy of the label’s Smoke & Mirrors Percussion Ensemble. About this recording Jim Hannon also wrote: “There’s an immediacy, clarity, and transparency to this modern classical percussion recording that seemingly brings the performers to your living room.” I couldn’t have said it better (or as well) myself. This record is a lot of fun, imaginative and absorbing. I played it both with and without the 212/SEs in the system. The performers sounded outstanding without the RELs, but with the subs activated, once again the instruments had greater body and just sounded more present in the room.

The home-theater experience with the RELs was a source of more good news. Factor in all of the good things the RELs do for music, add seismic power and punch on film’s low-frequency effects, and you have a sub that truly bridges the gap between great music reproduction and thrilling playback of motion pictures. I played a variety of films and was never disappointed. Thunder was more thunderous, trains and rocket ships left trails through the room, and even the occasional T-Rex left footprints on the floor. The great Hans Zimmer score for The Dark Knight was frightening and exhilarating at the same time. In the classic Das Boot, the U-boat is subjected to repeated rounds of depth charges launched by British destroyers intent on blowing it out of the water. Not joking, with the RELs in the system I jumped out of my chair the first time the depth charges exploded. The film provided me the rare opportunity to use a sub to review a sub.

In short, for home theater the 212/SEs do everything you would want a subwoofer to do. The size of my listening room expanded, impacts were palpable, and all instruments and voices seemed more three-dimensional. As they say, what’s not to like? Unless you have a very large theater room, it would seem to me that a pair of 212/SEs would get the job done in almost any home-theater environment. I have never come close to hearing the 212s strain and I know I will be unable to reach their output capabilities (well over 110dB) in my room. Of course, the fanatical home-theater owner could always add more 212s if he believed it were necessary, but I would never use more than a stereo pair for music reproduction.


The Bottom Line
In a word, the REL 212/SEs are sublime. Like a linebacker who loves to paint, they have the ability to hit hard when called for, but their more gentle side allows delicate brush strokes that infuse the midrange and upper frequencies with three-dimensional body and sheer presence. The degree to which the 212s improved the already excellent midrange and high frequencies of my system came as the biggest surprise. Their superb bass added a degree of air and space to the sound that, seemingly, only comes with quality reproduction of the low frequencies.

The 212s have made a believer out of this reviewer. I was skeptical that any high-powered subwoofer could actually sound seamless with full-range main speakers on all types of music. REL has shown it is possible. If they match with planar drivers, I’m confident it will be even easier to match the RELs with full-range dynamic speakers. I’m sure that other very good subwoofers can do the same, but the relatively low price, high output, and outstanding finish of the 212s make for a very compelling package. Believe it or not, REL offers two models that sit above the 212s in its product line: the G-1 MK II and the No. 25. These models are considerably more expensive than the 212s and offer 12″ or 15″ drivers, but are only available in single-driver/single-cabinet configuration. For greater output, they are designed to be stacked, two or three per channel. I am sure these subs are great, but to achieve the output capabilities of a pair of 212s would require four G-1s or four No. 25s—a very expensive proposition. If funds are no object, great, but for me a pair of 212s offers fantastic performance in a small footprint and at a down-to-earth price. I put my money where my mouth is and bought the review pair.

With the 212/SEs you get fabulous low-bass performance along with the impression of an electronics upgrade. Whenever I turned the subs off, the soundstage became smaller and voices and instruments became more two-dimensional. The 212s are fast enough and transparent enough to seamlessly mesh with fast planar drivers. In this day of über-expensive cables and electronics, it seems to me that $8400 for a pair of 212/SEs would offer far more sonic benefit than that same amount would achieve if you upgraded almost any other part of a high-end sound system.

In enthusiastically recommending the 212/SEs, nevertheless a final word of caution. To extract the great performance of which they are capable, one must be careful and judicious in room placement, as well as crossover and level settings. If you are looking primarily for “big bang” performance on movie blockbusters, it is doubtful the 212s will sound right on music. But if you move toward a subtler blend of the subwoofers with your main speakers, so that the subs never call attention to themselves, you will be rewarded with superior music reproduction and awesome movie nights. In short, I think you will be very impressed if you make the opportunity to audition the 212/SEs.

Specs & Pricing

Type: Subwoofer with two active 12″ front-firing drivers, one passive 12″ radiator on the rear and one 12″ passive radiator down-firing
Active drive unit: (2) 12″ long-throw, continuous cast alloy cone structure, cast chassis
Passive radiators: (2) 12″ continuous cast alloy cone structure, cast chassis
Lower frequency response in room: 19Hz at -6dB
Input connectors: High-level Neutrik Speakon, left and right low-level RCA, LFE RCA, SMA for wireless antenna
Gain control range: 80dB
Crossover range: 30Hz–120Hz
Amplifier power output: 1000 watts (RMS), “next gen” Class D
Phase switch: 0 or 180 degrees
Dimensions: 17.2″ x 32″ x 20″
Net weight: 122 lbs.
Price: $4200 each

800 Addison St.
Berkeley, CA 94710
(510) 990-6005

Kuzma Stabi M turntable with Kuzma 4Point ’arm; Lyra Etna, Koetsu Rosewood Platinum Signature cartridges; EMM Labs CD playback system; Aesthetix Eclipse Io phonostage with two power supplies; Aesthetix Eclipse Callisto linestage with two power supplies; Aesthetix Atlas Signature monoblock and VTL 750 amplifiers; Audio Research REF Phono 10; Audio Research REF 10 Line Stage; Audio Research REF 750 SE amplifiers; Purist Audio Design, Transparent, and AudioQuest cabling; accessory feet and room treatment devices by Stillpoints.

By Don Saltzman

My stock in trade for the past 45 years or so has been business litigation. If you are being sued for breach of contract or, better yet, you want to sue someone who has done you wrong, just give me a call. I love courtroom brawls.

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