First Sounds: Concrete Audio N1

by Roy Gregory | July 30, 2015

here’s nothing new about concrete. Man has been using it to build things since the Romans ruled the world, and sometimes it seems like people have been trying to build loudspeakers out of it for almost as long. Ranging from DIY enclosures molded using sandboxes to massive architectural elements that double as folded horns (or should that be the other way around?) concrete cabinet construction has always lurked on the outer reaches of the audio world. But one thing that seemingly characterized every example of the art (how can I put this?) was a certain absence of aesthetic finesse or surface finish. Oh, okay, let’s be honest: concrete speakers have always looked crude and blobby or angular and aggressive, more garden ornament than interior furnishing.

Until now. I first happened across (and reported on) Concrete Audio’s N1 loudspeakers at this year’s Munich show, and it wasn’t just the material that captured my attention. Here was a speaker with a concrete cabinet that didn’t just look seriously high end; at €27,000/pair (excluding tax) it was priced that way too. Of course, concrete has come a long way since the Europeans were using it mainly to keep their neighbors out. No fashionably high-ticket kitchen store is complete without examples of polished concrete work surfaces, while sealed concrete floors are all the rage in upmarket fashion houses and trendy office spaces. Even so, I was more than a little surprised by the elegant proportions and flawless, sculpted finish of the Concrete Audio speakers -- more so once I discovered that they use a genuine one-piece monocoque construction. Yes, the only gaps in the construction are for the drivers and terminals: no separate base or rear baffle and no access panel.

Now, take a look at the picture and think about that. This really is one of those How do they do that? moments, especially given that the interior volume, shape and proportions need to be molded just as precisely as those knife-edge contours on the exterior. I wish I could tell you the answer, but Frank Nebel of Concrete Audio just grins when asked and if pushed admits that the process is a closely guarded secret that took over a decade and more than fifty prototypes to develop. What he does reveal is that each cabinet is created in a single pour, the precise mix of cement, sand, water and other elements critical to achieving a homogenous structure, free of cavities or surface blemishes, that delivers consistent sample-to-sample sonic performance. Perhaps most impressive is that what you see is what you get -- straight out of the mold. The surface of each cabinet is treated with a sealant, but otherwise it emerges fully finished. For those who find the subtly grained natural concrete a little too modern, the sealant comes in a whole range of colors, so finish can be almost anything you want.

So much for the practicalities. The real question remains: is all the time, trouble and cost expended on that concrete cabinet worth the bother? After all, at 80 kilos per speaker, shipping these things isn’t exactly cheap or easy. As Marc Mickelson pointed out in his "First Sounds" look at Wilson’s Sabrina, one way that company has managed to keep costs down is to ship the speakers in cardboard boxes rather than the more familiar wooden crates.

Well, let me reassure you that the cardboard box that will safely contain the N1 hasn’t been built. Which is another way of saying that, irrespective of how you arrive at the final cost, the speakers need to sound just as good as their price peers from the likes of Wilson if they are going to survive in a crowded marketplace. The parts list certainly looks promising, with each speaker housing a pair of the familiar Scan-Speak slotted, pulp-coned midrange/bass units flanking the well-regarded ring-radiator tweeter in a classic D’Appolito arrangement, laced together using a first-order crossover. Given the slim, tapered back cabinet with its 1 1/4" thick sides and 2" thick front baffle, you don’t need to be Pythagoras to work out that the internal volume isn’t huge. Combine that with the relatively small swept area of the driver array and the claimed bandwidth of 34Hz to 40kHz 3dB and you’d be right to expect a low sensitivity. What you might not be expecting is a sensitivity quoted as 83dB coupled to a 4-ohm load! Fortunately, like the Vandersteen Model 7 Mk II, another speaker using first-order slopes and a super rigid, low-loss cabinet, the N1 sounds much more efficient and lively than that figure suggests. I listened to the speakers on the end of Naim’s massively powerful Statement amplifiers, but they barely broke sweat, even when asked to play seriously loud. Concrete Audio actually uses a 30Wpc class-A amplifier to drive the speakers in their own system.

Indeed, low loss is very much the order of the day when it comes to the N1. The concrete enclosure is massively stiff and rigid, yet enjoys excellent self-damping -- helped by a firmly attached, heavy felt lining. The careful shaping of the internal volume eliminates the need for extensive lossy internal damping materials, with just a very loose filling of natural wool, while the 6dB slopes used in the crossover allow for a simple circuit using the fewest subtractive elements. Bolt your lightweight drivers firmly to such a solid foundation and you can expect the best possible energy transfer.

All of which explains why the N1 makes the most of the signal that it’s fed and the power doing the driving. There’s no sense of lag or sloth at all. In fact, the most obvious initial impression is just how silent those concrete cabinets are. The soundstage is big, genuinely three-dimensional, transparent and set well back behind the plane of the speakers, with nothing to suggest that the music emanates from the speakers at all. If anything, the presentation is more reminiscent of a speaker like the Quad ESL-63 (in more ways than one) than the more conventional box competition. The spatial coherence and dimensionality are matched by the seamless integration of the drivers, all helped by the incredibly even, peak-free energy spectrum generated. Music is notably uncluttered and unimpeded, with an excellent sense of pace and flow. Dynamics are slightly muted and smaller in absolute scale than they might be, but let’s not forget that this is not a large speaker with large drivers to throw air about.

What is impressive is just how accurately scaled and acutely observed dynamic shifts and instrumental textures are, beautifully presented in a coherent musical context. With Lisa Batiashvili’s gorgeously realized reading of the third movement of the Shostakovich Violin Concerto No.1 [DGG B0015203-02], the grace, poise and emotional intensity of her playing is clearly evident, the N1 cutting right to the expressive core of this performance, despite a less-than-stellar recording. Believe me, that’s no mean feat, sonically or musically.

You might argue that hanging the Concrete Audio speakers on the end of the Naim Statement amps, driven by a full dCS Vivaldi stack, that’s the least you might expect -- and you’d have a point. But the speakers still have to deliver the musical goods. What I found so interesting was not just their ability to grasp the musical sense in a whole host of different recordings of different music, but also how clearly they reflected the nature and qualities of the driving system. The musical strengths (or weaknesses) of the various filter options on the Vivaldi DAC were clearly, almost explicitly revealed, as was the absolute spatial and temporal security and stability of the system, a combination of equipment that anchored the music in space but also allowed it to breathe at its own tempo. Likewise, the security of the disc source over the high-res streamer was almost cruelly apparent -- all done without the speakers ever drawing attention to themselves. This ability to stand aside from the musical performance, to project a natural, stable and uncluttered image, one with clarity and convincing dimensionality, while also preserving the sense and shape of the music itself mark the Concrete Audio speakers as worthy of further attention. Their cabinets and design approach aren’t just different -- they’re clearly effective. The result is a genuinely expressive and musically neutral loudspeaker.

This first taste leaves me looking forward to a more extended audition -- and a chance to dig deeper into the speakers’ lower registers, one thing that wasn’t really possible in the room and setup in which I was listening, where the acoustics dictated a placement leaning toward that clean midband rather than bass reinforcement. A different space would almost certainly provide deeper bass -- and possibly wider-ranging dynamics too.

For Concrete Audio it has been a long, long road -- but judging from my first real audition it has been well worth the journey.

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