Copper has an exchange program with FIDELITY magazine (and others), where we share articles, including this one, between publications.
Curiously enough, SPL is rarely considered a criterion when defining what characterizes an exquisite, high-end loudspeaker. Yet the ability to push volume without distortion is a key requirement for a sound transducer (even if I assert this only off the record). And the Pure Emotion 1.0 by AW masters this discipline like no other. A visit to a superlative.
108 decibel sensitivity and a maximum distortion-free sound pressure of 120 decibels: that’s what I had read in the data sheet just a moment ago. An impressive figure for a loudspeaker — for any loudspeaker, no matter if it features an active, passive, classic, or horn design. And yet all I had were figures, which in no way prepared me for what was to follow: “I’ll put something dynamic on and crank it up a bit. Then you’ll hear what the speakers can do,” said a smiling Axel Wurm in his unmistakable Hessian dialect. And with that, he pressed the remote app’s Play button. In the next moment, a drummer began to pedal his kick drum with a vengeance while pummeling his snare drum into submission. When the sound reached me, I felt as if an unknown force was ripping the base from my brain. The shock wave surged through my body and had me searching, mildly dazed, for something to hold onto. No doubt about it – my visit to Pure Emotion by Axel Wurm left me impressed!
Any mention of [a technical term like] “stable impulse response” would have been a mockery given the two towers rising in front of me. Terms like “elemental force,” “explosive character,” or “steam hammer” would have hit the mark much better. The Pure Emotion 1.0 not only generates high acoustic pressure, it also launches its output into a listening space so fast and abruptly, you don’t have time to think about it.
Carsten Barnbeck and Axel Wurm check out the horn driver of the Pure Emotion 1.0.
On top of that, as deafening as it may have seemed at its fiercest, the speakers’ broadband impulse resonated with absolute cleanliness, nuance and stability, even at this level. And still, the best was yet to come from this floorstanding speaker. “We set them up on a friend’s property out by the lake and then really pumped up the volume: even at a distance of 30 meters, it was so loud you couldn’t hear yourself speak,” the proud design engineer would later throw out as a small anecdote.
A Hobby Project With Consequences
But let’s start at the beginning: Last fall, we, along with many other visitors to the Westdeutsche Hifi Tage (Western German Hi-fi Days) trade fair, unexpectedly stumbled into Wurm’s demonstration room. There in the huge parlor space located in Bonn’s Maritim Hotel we heard an understated, thoroughly stylish Audio Agile front end making music attached to a pair of monumental, exceptionally-designed, and, for their size, surprisingly unobtrusive hybrid horn speakers. During the trade fair, Wurm had explained they spent two days and nights tweaking the tuning in that challenging space before the equipment produced music like they wanted to hear. His efforts were rewarded. The loudspeakers were remarkable not only because of their dimensions and their unique fabric covering. They also delivered such a clear sound and played with such speed and dynamism in this huge parlor space that they were showered with multiple standing ovations at the end of the demonstration. A brief “hello” followed by a conversation with the creator of the Pure Emotion 1.0 led to our realization: that’s where we need to go!
And then I found myself sitting in a room measuring just under 50 square meters plopped in the center of Erlensee near Hanau, Germany, eying up the exact same audio chain that served up such an impressive treat in Bonn. The scene described at the beginning does, of course, reflect one extreme facet of Pure Emotion’s 1.0. The loudspeaker can also exhibit discipline when it plays, expand any stage into a beguilingly large, trim space, and infuse the room with subtly melodious vocals. Wurm explained to us the idea behind this almost unfathomable power, turning to the popular Rolls Royce analogy: no matter how exacting the requirement might be, the speaker has a sufficient measure of performance to master it with fleet-footed aplomb. And its brute force didn’t appear in the slightest to diminish its flair for dynamic intricacies and precision, as I would learn from many other musical examples. Even at very low volume, the Pure Emotion 1.0 resounds in broadband and in full; it reveals holographic reproduction and doesn’t obscure even the minutest detail.
Every inch of the speaker’s 82 inches reflects exceptional design. Forming its essence is an amazingly light Swiss pine frame, a material used to make musical instruments. In the experience of this indefatigable inventor, the material enables a transducer of this type to deliver its especially sublime sound. The supporting base was devised to be dismantled in an instant and transported while having as little mass as possible — a pretty tricky challenge to get a handle on.
Wurm spent many years fine-tuning the design for his base, modifying, bracing, and reinforcing it in places, before it was able to withstand the Pure Emotion 1.0's enormous acoustic pressure with zero vibrations and low resonance.
That might sound like trial and error, but it did, in fact, draw on decades of experience. Born in 1959, Wurm had, at the tender age of 13, already embarked on that effort that had left its mark on so many designers of his generation: equipped with a hand cart, he retrieved old — even defective — tube radios and TV sets from his relatives, from the refuse, and from his wider circle of acquaintances, then dismantled them, examined their circuitry, and created something new from them. So by the mid-1970s, it had become completely normal for him to meet his high-fidelity needs out of his own resources.
And his passion for high volume had already taken hold back then: loudspeakers like JBL’s 4343 served the music enthusiast as his archetypes.
A birthday gift in 2000 would eventually awake him from his “deep sleep,” as he would ultimately describe this key moment. His wife, inspired by a good friend, gave him a set of Focal Beryllium tweeters. He promptly tried out these four-inch units as midrange drivers in one of his loudspeakers and was astonished, flabbergasted, simply bowled over at how much sonic improvement these drivers provided. Vocals suddenly seemed so three-dimensional and natural that the experience marked a new chapter in his obsession.
The range of his required sound attributes had now grown to embrace linearity, detailing, microdynamics, and clarity. Wurm was, of course, already familiar with these aspects, but at that point they became his passion.
Like a Chameleon
Wurm’s devotion to design and styling constitutes another constant in the engineering of his loudspeakers. The veteran do-it-yourselfer loves trying out colors, shapes, and exotic material mixes. So, he showed us one of his earliest high-end design studies in his living room: loudspeakers in the form of two giant harps, accompanied by huge furniture-looking subwoofers.
In his Pure Emotion 1.0, he has integrated the four bulky 12-inch bass drivers directly into the primary frame. In combination with the carefully-calibrated bass port, this quartet achieves an acoustic pressure of more than 100 decibels at a bloodcurdling 18 Hertz. To complement this bass power, Wurm decided at some point in the design process to add a horn driver to [the speaker's] midrange-tweeter arsenal. A spherical wave horn with a 30-inch diameter proved to be the optimum solution. It’s made of a complex wood/plastic/iron/aluminum composite. His son took 60 hours to apply the 24-carat gold leaf finish on the demonstration model by hand, which was then further worked on until the desired distressed look was achieved.
One final challenge proved to be the loudspeaker’s exterior finish: Wurm tried out all kinds of materials, until his wife into his head the idea of wrapping the speaker in fabric, analogous to Christo wrapping the Berlin Parliament building in 1995. What started off as “we can give it a try” turned out to be spot-on: it’s not just that the fabric gives the 1.0 its unmistakable, unique look. The jacketing proved to be the ideal insulation for the four bass drivers, and it makes the Pure Emotion 1.0 durable. Scratches, dust, or fading are alien to Wurm’s loudspeaker. And should it get stained, then just wash the fabric by hand and it’ll gleam like new.
This design has also made it possible to visually customize the loudspeaker to meet any requirements its owner might have. Wurm has already tried versions with printed fabric (take a look at the manufacturer’s website), and there have been practically no limits to how the horn can be finished, provided its basic function is not impaired.
The same applies to fine-tuning the sound quality of these giant columns: the loudspeaker’s incredible performance data has naturally entailed a few issues. A transducer that delivers even the lowest octaves at such sound pressure only actually functions perfectly in acoustically [optimum environments]. This is something you rarely find in residential spaces. That means the Pure Emotion 1.0 has to be controlled from a computer, like a super sports car. This job is done by an external DSP unit that connects between the source(s) and amplifier. The programmable filters operate on the FIR (finite impulse response) principle, which provides three benefits: limited latency (computational time lags), low computational power [requirement], and, as a result, a potentially very large quantity of equalization bands.
The Pure Emotion 1.0 thus fulfills all the criteria you would expect of an exclusive super-speaker: Its design and construction are unique, every detail on the handcrafted loudspeaker can be customized to meet the requirements of its owner, and it delivers superb performance in tandem with every conceivable amplifier. Yet that’s not the end of the story: Axel Wurm is aiming to provide his 1.0 with a younger sibling in the foreseeable future — the prototype is already being put through her paces. That means we’ll be hearing a lot more from this resourceful native of Hanau…
Pure-Emotion by AW
Leipziger Str. 2
63526 Erlensee
Germany
Phone +49 171 9558187
www.pure-emotion-audio.de
