Duevel Bella Luna
by Steven R. Rochlin
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The only way to begin this review is to enlighten you on a dream of mine. Many years ago, when Platinum Audio was still in business, they made a $150,000 loudspeaker called the Air Pulse 3.1. It was massive in both size and weight. They featured a unique 360o driver front wave dispersion design for all drivers. While i was the only member of the press to ever see the inner working and construction of these landmark loudspeakers, my hopes were that a smaller, more reasonably priced version would be marketed. Alas, they lost their genius head designer Phil Jones (who now heads American Acoustic Development and also assists in designing loudspeakers for Soliloquy Loudspeaker Company). While the Platinum Audio Air Pulse 3.1 earned countless awards and was featured within many magazines, there would be no smaller version until...
Upon attending the 2001 Frankfurt, Germany High End Society show at the Kempinski Hotel in mid June i saw and heard my dream! It was a revelation that was not soon forgotten. In fact the Duevel room was awarded the coveted Enjoy the Music.com™ Best Of Show Award! So what made this experience so special as to rise above the other rooms? Glorious harmonics, extreme clarity, a great sense of scale and dynamics... just to name a few of the traits. Needless to say i simply had to find a way to review these loudspeaker even though there was no official United States distribution. A few e-mails back and forth with the ever gracious Markus Duevel were intermingled with customs snags and rip-off import brokers/delivery men... Eventually after solving those nasty "Imperial Entanglements" the Duevel Bella Luna loudspeakers were in my main system! Importing products can be a major pain in the you-know-where, though as they say "No pain, no gain." So what makes these loudspeakers so very special that a cynical "been there, done that" kinda guy go crazy trying to review a piece of audio exotica?
An ingenious design that leaves the usual rectangle boxes or megaphone horn designs seem "old school" (as they are). Instead Duevel has employed an interesting wooden omnidirectional radiator that disperses the loudspeaker's drivers output 360o. Projecting a tight, narrow and focused output of a loudspeaker's drivers may be good if you hold your head in a vice, the moment you move your head the entire experience may be lost. This is a complaint some panel loudspeaker music lovers admit to. When you are in the small "window" all is great, but move your head away from this narrow opening and the glorious 3D soundscape (and frequency/harmonics) are compromised. In fact one manufacture of electrostatic loudspeaker knows this fact and purposefully curves their panels to assist is providing a slightly larger "window" into the music (Martin Logan). Of course there are various ways to design a loudspeaker for 360o sound dispersion.
mbl loudspeakers are heralded for their capability of 360o distribution, though they use multiple drivers within the same frequency to achieve this. While multiple drivers reproducing the same frequencies on the vertical plane (D'Appolito) is ok, but multiple drivers reproducing the same frequency on the horizontal plane is not good. Bad bad bad as the ear is more sensitive to right/left than it is for top/bottom! Worse still, the mbl design is implemented in such a way as to have a devastatingly low 81 dB/w/m. To add insult to injury, the loudspeaker has a low 4 ohm impedance! One would need an amplifier with amazingly high wattage and drive capability as to suck your wallet dry unless you are Bill Gates or Steve Jobs! Ok, maybe not a billionaire like good ol' Bill and Steve, though you would require some mighty expensive amplification never the less. Surely there has to be a better way. So now that we know about the bad and the ugly, it is time to discover the good.
Enter The Bella Luna
As Steve Jobs would like us to do... Think different. Markus Duevel has decided to wisely employ a unique one tweeter/midrange and one midbass/woofer driver. Furthermore, the entire design is highly efficient as to produce a comfortable (for low wattage single-ended tube amplifiers) 92dB/w/m sensitivity and presents a sane 6 ohm impedance. Better still the design produces a 40 Hz - 20,000 Hz that i fully agree with after months of listening pleasure. So how does Duevel accomplish such an impressive result?
Duevel Bella Luna Top Section
Looking at the top section you can see the rear magnet of the tweeter/midrange at the top. This driver fires into a specially angled 360o horn so that the drivers output exits out between the two wooden omnidirectional radiators. Meanwhile the mid/bass woofer fires upward so that the output is dispersed by the lowermost omnidirectional radiator. This effectively makes the entire loudspeaker's output 360o. without the use of unnecessary (more) drivers. To get a better ides, here is a 3D CAD (computer Aided Design) drawing of the omnidirectional radiators (see below).
3D CAD Of The Omnidirectional Radiators
Deuvel's Bella Luna Driver Output
Of course a great design such as the above is worthless of one uses less than optimum drivers. So some of you died-in-the-wool horn guys are probably thinking "Duevel uses a compression high/mid unit". Nope! Do they use a smooth silk-dome tweeter? No way. How about one of those "space aged" aluminum or titanium dome tweeters. Not a chance! How does a unique 38mm carbon fiber dome with Nomex voice coil former sound (pun intended)? A what with a who?
Ok, i will drop all the techno-speak and simply let the above dissection of the tweeter driver speak for itself. As for the midbass/woofer unit, it too is made of carbon fiber. Specifically, it is a 22cm carbon fiber cone with sturdy die cast chassis and textile (cloth-type) suspension. The use of carbon fiber on both drivers was chosen due to their extremely low mass and high stiffness. That is exactly what virtually all driver designers aim for. It allows for high driver agility that can result in low distortion due to high controllability. A minimalist crossover using audiophile grade parts to allow the loudspeaker to produce a linear phase output. The cabinet itself is extremely rigid and well braced. The rear output from the woofer is ported from the bottom of the unit to aid in lower frequency reproduction.
There is one last noteworthy comment concerning the implementation of a 360o horn design. This being both the direct and reflecting sound reaching the listening position. While Imperial knowledge would say that all the bouncing of sound within the room with be devastating to the clarity and image focus, there is more than meets the eye, er, um, ear. To quote the Duevel website (slightly edited for correct United States English):
"When listening to extremely focusing loudspeakers which therefore produces few indirect sound, the listener hears the direct and indirect sound of the recording in a spot beam from one direction. This is, however, a completely unnatural sound situation because the indirect sound of the recording will not be distinguished by us through time masking effects. As a result we distinguish this as a flat acoustic pattern. It is known that small two-way loudspeakers have got a wide beamwidth and therefore they show a depth stepping. The world-wide success and acceptance of some representatives of the species of dipole (radiators of 1.order) certifies to this system a better realization. The ideal, however, is a point source (radiator of 0.order, monopole) with a perfect omnidirectional radiating behavior. This ideal is mostly reached by an omnidirectional radiator. It is necessary to take care precisely of a phase- and time constant radiation to avoid that the room information won't be clear.
From the psycho-acoustic point of view it is therefore not true, that omnidirectional radiators add something to the music signal with the room reflections, because the opposite is true, only if there is a homogeneous ratio between the sound signal and the sound field you can enjoy a natural music reproduction."
Of course what really matters is how a product sounds within one's listening room. So let's take these German-made Bella Luna loudspeakers on a test drive!
Wir Fahr'n Auf Der Autobahn
Setup was not overly sensitive in my listening room and the best position seemed to be about three feet from the side and four feet from the rear wall. During the first hundred or so hours the tweeter seemed to get a bit smoother while bass became a deeper and more satisfying. In fact the bass reproduction within my room was quite impressive! This was especially true with acoustic bass. Tight and tuneful is what my notes here say. Upon playing my favorite Miles Davis vinyl record from the Analogue Production The Great Prestige Recordings box set, Cookin' With The Miles Davis Quintet, Paul Chambers acoustic bass had a wonderful balance of string, instrument body and tone. The drums, too, had just the right sound and harmonic structure. While the imagine was not quite as focused as my reference Avantgarde Acoustic Duo loudspeakers, the overall gestalt of the performance was happily evident.
If there is one item this reviewer demands to be properly reproduced, it is a sense of balance and harmonic rightness. The uppermost frequencies seem to lack a small amount of extension, yet never were overly detracting. In the end a nice overall sound. After all, if the natural harmonics in the midrange are not rendered well then surely there are frequency response errors (usually within the crossover region) that will forever irk the musician in me. In fact one of great challenges within loudspeaker design is not only choosing two drivers that will work well together, but also in designing a crossover to get the best as each driver passes along the exiting frequency to the next. As the larger driver reduces producing higher frequency notes, it is how the smaller driver commences in producing those frequencies upward that are crucial. Not just in volume level, but also in phase as well. This is where a design such as the Duevel with its phase linear design shines over others designs. Back to the music...
Both male and female voice were also reproduced with aplomb. From Billie Holiday to Louis Armstrong, the Duevel Bella Luna seemed to capture the soul of the music. before i forget to mention, due to the ease of driving these speakers, my favorite eight watts single-ended tube amplifier, the Wavelength Audio Cardinal, was the best match overall. While these loudspeakers can easily handle well over 100 watts, in my listening room only eight watts was all that is needed for sane volume levels.
As i mentioned earlier, the individual instrument imaging was not as focused as i would have liked, though there was an amazing rendering of soundscape that was a revelation. This was especially true with recordings such as Roger Waters Amused To Death [Columbia CK 53196] as well as the original UK pressing of Pink Floyd's Dark Side of the Moon [E.M.I. Harvest SHVL 804). For those of you unfamiliar with Amused To Death, it was recorded is Q-Sound. This type of recording is processed with psychoacoustic effects to produce an extremely wide, deep and totally surrounding experience. Here is where the Bella Luna shines. While other loudspeakers would transport me into this synthesized soundscape, the Bella Luna seemed to be more seamless. There was also a wonderful reproduction of the small musical cues surrounding me that enhanced this acoustic space transportation.
As for Dark Side of the Moon, it too has some interesting surround sound type effects and there was also a great sense of both large and small scale surround. After many other recordings came and went, it seems the easy of dynamic both macro and micro help to aid in the feeling of a more natural, honest (so to speak) surround reproduction. For those of you who (generally) muck up your listening experience with more than two loudspeakers must realize that the more loudspeakers you use, the greater the problems with time and phase alignment. While guys like Tomlinson Holman who would like us to believe 5.1 or 10.2 channels are great, they neglect to tell you about the ever narrowing of physical space where a truly aligned sound occurs. Dealers may not tell you this either as they can sell you twelve loudspeakers and amplifier channels. The more profit the better!
The Bella Luna with its natural 360o sound dispersion seems to provide the benefits of properly done surround sound yet without the obvious problems as you only need two loudspeakers. Of course this type of sound effect must be on the recording. When playing monophonic recordings all that was produced was a nice central image with good front stage depth. These loudspeakers are not like the "marketing genius" Bose with their "Direct Reflect" sound that just throws sound all over the place. The Bella Luna are carefully designed to produce time and phase aligned 360o sound dispersion. And to cut to the chase...
Final Reflections On The Bella Luna
Overall, my feelings are that the Duevel Bella Luna are among the top echelon of designs that will bring many hours of musical bliss. This is a full range design that can easily be driven with good quality solid-state and low wattage tube amplifier without the need for super he-man amplifier control due to inefficient design. The dynamics, while not equaling my 103 dB/w/m horns, are very impressive in their own right. These loudspeakers excel in easily bringing the listener into the recording's acoustic space. Harmonically, the Bella Luna are extremely satisfying... even to a longtime musician such as myself. Before i forget, visually, these babies are unique and exceptionally beautiful. With six wood wood finishes to choose from, they should easily win that coveted "significant other approval" (or as some say, WAF). Of course in the end what really matters is that you...
Enjoy the Music,
Steven R. Rochlin
|Sub-bass (10 Hz - 60 Hz)||80|
|Mid-bass (80 Hz - 200 Hz)||92|
|Midrange (200 Hz - 3,000 Hz)||92|
|High-frequencies (3,000 Hz on up)||92|
|Soundscape width front||100|
|Soundscape width rear||100|
|Soundscape depth behind speakers||100|
|Soundscape extension into the room||100|
|Fit and Finish||100|
|Value for the Money||95|
Type: Omnidirectional two-way full-range horn
Cone Diameter - 22cm carbon fiber cone with
die cast chassis and textile suspension
Voicecoil - 38mm
Ferrite Magnet - 140mm
Weight - 3.1 kg
Cone Diameter - 38mm carbon fiber cone
Voicecoil - 38mm with Nomex voice coil former
Magnet - 132mm
Weight - 2.6 kg
Cabinet Structure: Struted and interlocking cabinet
Crossover: Phase linear crossover
Frequency Response: 40Hz - 20,000Hz
Impedance: 6 ohms
Power Handling: 150 watts
Wood Options: Cherry, Ice Birch, Maple Cluster, Maple Burl, Pacific Maple, and Walnut Burl.
Overall Weight: 35 kg
Overall Dimensions: 280 x 280 x 1040 (WxDxH in mm)
Warranty: Five years
Voice: +49 (0) 5475-1623
Fax: +49 (0) 5475-1623
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