FLOORSTANDING LOUDSPEAKERS

Blumenhofer Acoustics
BIG FUN 20

Srajan Ebaen
srajan@6moons.com





Financial Interests: click here
Source: Esoteric/APL Hifi UX-1/NWO 3.0GO
Preamp/Integrated: Esoteric C-03 (transistor), ModWright DM 36.5 (valves)
Amplifier: ModWright KWA-150, FirstWatt F5, Yamamoto A-09S, Ancient Audio Single Six
Speakers: ASI Tango R, DeVore Fidelity Nines, Zu Essence
Cables: Complete loom of ASI Liveline
Stands: Ikea Molger and butcher-block platforms with metal footers
Powerline conditioning: 2 x Walker Audio Velocitor S
Sundry accessories: Furutech RD-2 CD demagnetizer; Nanotech Nespa Pro; extensive use of Acoustic System Resonators, noise filters and phase inverters
Room size: The sound platform is 3 x 4.5m with a 2-story slanted ceiling above; four steps below continue into an 8m long combined open kitchen, dining room and office, an area which widens to 5.2m with a 2.8m ceiling; the sound platform space is open to a 2nd story landing and, via spiral stair case, to a 3rd-floor studio; concrete floor, concrete and brick walls from a converted barn with no parallel walls nor perfect right angles; short-wall setup with speaker backs facing the 8-meter expanse and 2nd-story landing.
Review Component Retail: starting at €15.500/pr

Haven't heard of Blumenhofer Acoustics before? You probably have. Without knowing it. Thomas Blumenhofer was the designer and manufacturer of Willibald Bauer's FJ speaker line. This included the omnipolar model FJ Om. For us, John Potis reviewed it in November 2005, then reader Frederic Beudot purchased it and subsequently joined 6moons where he penned a Take 2 for his first contribution. Willi Bauer of course is the man behind dps. dps is short for der platten spieler. That's the record player to us englische menschen. Because of one-sided sales, a few years ago Blumenhofer pulled the plug on the collaboration. After all, dps was and is a turntable outfit first and foremost. Thomas resolutely decided to chart his own course. The Om remains current but now sells adorned by the formal Blumenhofer Acoustics decal. This segues directly into today's assignment. It's the introduction of a new but really quite old brand.



Blumenhofer and speaker design/manufacture go back 30 years. That's for how long Thomas has already serviced this sector, albeit in sound reinforcement to explain why hifi nutters haven't officially made his acquaintance. Thus Blumenhofer Acoustics is both old and new.
The old is highly relevant because in pro, custom solutions are the norm. One single installation might require 150 pairs of speakers variously adapted for the occasion. Keeping up any such one-upspeakership for a goodly period of time -- since 1979 certainly qualifies -- and that elusive thing experience quite massively compounds. In short, live sound is Blumenhofer's reference, big hornspeakers are his obsession. Little surprise then that his emerging hifi brand includes mostly horns. At present those are tweeter horns married to ported bass in the Genuin Series (models 3 and 1 shown right above) and tweeter horns mated to floor-firing and folded back horns for the bass (the two Fun models on top of the page).



I first encountered Blumenhofer Acoustics at the 2008 fall TOP Audio show in Milan. They showed a big Genuin model with prototypes of their (still forthcoming) valve electronics. Marketing director Andrea Vitali later solicited me for a review. The timing of that solicitation a month prior to the HighEnd 2009 show in München meant that he already had the two new models available. And the Genuin 3. Which one did I want to test?



Since Thomas had bought a mondo van in January; and since he and Andrea had proposed a personal delivery; I inquired whether they could bring all three models. I'd pick one in situ to assure compatibility with my room and electronics, they'd take back the other two right after their visit. And that's what they did.



Starting at €5,000/pr, there was the new Fun 17 model. It combines a 35mm Mylar tweeter behind an oval MDF horn with a 6.5-inch mid-woofer via a 12dB electrical, 18dB acoustic network at 1.8kHz. F3 with steep rolloff below it is 40Hz, in-room sensitivity 92dB (anechoic 89dB) and approximate weight 25kg. Cabinet construction is 18mm Birch Ply, the geometry avoids parallel walls except for the sides and the internals sport a compression chamber for the woofer. Behind that chamber's carefully calculated throat opening, the internal horn line doubles back up in a flare, then turns around and fires into the floor to create the desired radiation resistance for the driver (the tweeter's in-house crafted rear chamber is sealed). All cabinet walls are heavily lined to absorb midrange frequencies above 300Hz and horn gain below that is ca. 3dB. Standard finish is Birch, a €600 surcharge adds Walnut or Cherry and €6.500 total buys Olive veneer. As for the other two models, an impedance correction network linearizes the ohmic peak at the crossover point which for valve amps would be more challenging. This correction network can be disabled by pulling the jumper in the crossover cover of the horn mouth.
The second speaker brought was the Genuin 3 set up below. It weighs in at €8.500/pr in Birch veneer and about 30kg. Its sensitivity spec of 92dB in-room duplicates the smaller rear horn but the tweeter becomes a 45mm Titanium unit with 1-inch horn throat and the mid/woofer grows to eight inches. The crossover point hovers at 1.3kHz and the enclosure runs 25mm Birch Ply panels with a 50mm double-thick front baffle.







Unlike the smaller rear horn, the Genuin 3 sports a separate wood-clad tweeter horn module which can be moved for time alignment but then requires unbolting the woofer to gain access to the adjustment screws. The Genuin 3 terminal plate runs biwire Eichmanns jumpered with wire leads and between them, the impedance correction circuit jumper which can be removed for transistor amps. Personal experimentation determines whether with or without impedance correction is preferable in the listening seat and for a given amplifier. As the front-firing port shows, the Genuin 3 is a bass reflex design. Unlike the two rear horns which use metal bars to mount their spikes or optional footers, the Genuin 3 incorporates a dedicated black plinth. Its front is narrower than the enclosure to bestow upon the latter a somewhat floating illusion from the seat.
The edge mitering of the enclosure exposes the striated Ply layers while the machined MDF horn is painted flat black, the mounting flange textured black. The decorative engraved line pattern on the front baffle varies from speaker model to speaker model.



The Big Fun 20 relies on a 65mm Titanium tweeter and also enlarges the horn throat to 1.4" to apply a high 1:10 compression ratio. The mid-woofer coming in at 1.2kHz and 18dB/octave acoustical is an 8-inch paper sandwich with foam core and built to Thomas' specifications by a pro audio drive unit manufacturer in small custom batches.



The externally adjustable tweeter horn module adopts an exposed metal mount. The loaner's only two items not finalized were the textured paint on the rear tweeter housing and the hair-line calibration sticker surrounding the locking bolt to assist precise physical offset as determined by a listening distance chart in the owner's manual.



With the module removed, the enclosure top shows the two banana terminals for the tweeter connections.



The terminal plate duplicates the one from the Genuin 3 (correction network jumper removed for illustration).



Unlike the smaller rear horn, this one applies only half the internal damping though the overall geometry of the folded horn is quite similar.



This enclosure too is crafted from 25mm Birch Ply with a 50mm double baffle. Proper T-nuts allow high torque bolting of the woofer basket for proper coupling. The crossover hides behind an access panel in the horn mouth flare.



The impedance correction circuit consists of the following three components:



All crossover parts are matched to 1%, all drive units are pair matched and extensively rebuilt and recalibrated over roughly 1.5 hours for each driver.





Thomas had brought two raw tweeter horn blocks. They showed the twice or thrice bonded slabs of MDF already machined out to the proper tolerances and dimensions of the oval horn flares (solid wood versions are available for a surcharge). Each speaker model's horn is precisely matched to the driver and only works for that particular driver.
This suggested extensive prototyping. One cannot yet successfully apply predictive software modeling to determine horn geometries. Asked how many horn matching iterations a given driver required, Thomas quipped "perhaps two, perhaps twenty. But sometimes, I have to junk the driver. Not all drivers are appropriate for horn loading. Some of that can't be gleaned from the driver's specs alone. You have to model and fabricate the horn first, then measure it with the driver. "The laborious prototyping applies to the back-horn enclosures as well. The size and geometry of the compression chamber, the diameter of the throat and the length of the line plus the amount of internal damping are all critical and, again, peculiar to a given driver. If you were to copy any of my enclosures perfectly but didn't run the same driver, it wouldn't work properly. And, our drivers are built to our own specifications and proprietary." Thomas grinned contentedly. He seemed like a man secure in knowing that his craft would never become an open secret.
His is a small enterprise with three employees working out of a house he built in the midst of a German national park. Just to obtain the building permit in this pastoral setting took a few years. And significant funds. Clearly Blumenhofer is both resourceful and stubborn. He lives and breathes the Old World artisan approach and is involved in every aspect of the operation. Spraying the heavy catalysts, solvents and paints ubiquitous for the finishes of PA speakers took a heavy toll on his health despite respirator protection. "Nobody could do the spraying. Or perhaps they simply didn't want to learn. So I did all of it for thirty years." He stopped that only three months ago. For hifi, he prefers hand-waxed wood finishes to high gloss and lacquers (though piano gloss is available but outsourced).
Because of his familiarity with the customized nature of the pro sector, Thomas applies the same spirit to hifi. "If you have particular requirements or desires, don't hesitate to communicate them. Chances are very high we can accommodate you." That's exactly how the forthcoming 3-way statement horn speaker project was born.
Blumenhofer Acoustics thus is a prototypical handcrafter's operation positioned as the polar opposite to the high-volume offshore producers. "Those who value the lowest possible price above all else must continue to shop somewhere else. Those who want something better and also want to support the handcrafter's way of doing things will feel right at home with us. Made one at a time by skilled artisans in Germany really is what we're all about."



Anyone comparing performance specs between the three models which competed for attention in Casa Chardonne over a day of musical chairs will agree that they aren't separated by very much. Over the other two, the Big Fun 20 adds about eight cycles in bass extension and 3dB of sensitivity. And a bigger box. That's about it. Even the impedance plots of the back horns mimic the typical saddle curve of the Genuin 3's ported alignment. Why the more complex back-loaded horns? "It isn't for sensitivity nor easily measurable behavior per se. Horns simply sound different. Conventional speakers mostly bore me. They lack the energy and charge of the live performance. I've built horns the size of a garage to know the difference. But in sound reinforcement, winning contracts is usually a matter of money. These tend to be big jobs so the guy with the lowest bid often signs the contract. It's not ultimate performance then that wins the day. So I branched out into hifi. There many customers are a bit more critical, sophisticated and appreciative. And yes, we are already working on a 250kg big statement hornspeaker with 21-inch woofers. Two pairs are pre-sold."
My selection audition determined that while the three models do share a clear house sound, the upsell qualities are immediacy, jump factor and resolution. The smaller rear horn is even softer on the attacks and less capable of properly energizing a sizeable room. It makes for easy listening without the dialed-for-speed aspect which most associate with horns. It's a soft horn sound, pleasant and 'musical' but a bit polite for my taste. Both my Zu Essence and DeVore Fidelity Nines reach lower into the bass and offer more overall articulation yet are priced comparably or lower.



The immediate differentiator between the Genuin 3 and the Big Fun 20 is tweeter quality. The more expensive speaker has the even better HF unit. It makes for a more lit-up, dimensionally more insightful presentation and higher PRaT. Down low, there's a bit more extension but the last 10 cycles are missing in action. The 'full' horn also has a small edge in overall liveliness or subjective speed over the ported design. While the sensitivity of all three models generated plenty of SPLs over my 8wpc Yamamoto A-09S, both Fun models seemed to favor the lower output impedance and higher current of the 18-watt  Ancient Audio 6C33C Single Six monos, FirstWatt F5 and ModWright KWA-150. For traction, the 300B amp worked best into the Genuin 3. This perhaps indicates that the large openings of the back horns with their high floor gaps appreciate more control.

For reviewing in my space with my gear, it was down to the Genuin 3 and larger back horn. The former already had a few reviews under its belt whereas the latter would be formally introduced only at the May Munich show. Plus, I slightly preferred its sound. Big Fun 20 stayed then. Perhaps most relevant when viewed against Thomas Blumenhofer's pro background is how the Big Fun 20 treats attacks - softly. It makes for a laid-back cozy sound. Meanwhile most hifi readers flash on a bright, hard and loud sound whenever Public Address systems are mentioned. Add horns and presumptions could spiral out to include ultra fast, ultra dynamic and incisive bite, perhaps even steeliness. How audiophiles regard older consumer-grade Klipsch speakers might serve as the archetype.

But nothing could be farther from the BF20 sound. Neither the maker's pro-sound history nor the speaker's horn concept play to such generalized if rash assumptions. The only visual that sonically translates is what a larger woofer used for midrange duties might predict. Instead of pushing brilliance and exactitude, one gets a bigger, warmer sound. It's geared more for comfort than speed. If that had been your assumption just looking, it bears out. In the usual sense, the adjustable physical time alignment does not. Unlike most designers who even bother with so-called phase coherence -- and most of them don't include adjustable modules -- this Blumenhofer model shuns the customary 6dB/octave crossover. As mentioned, it favors a 3rd-order acoustical slope. This could tie to an observation I couldn't shake, particularly as long as my ears were still aligned to my 1st-order ASI Tango R or Zu Essence speakers. I struggled with a lack of perkiness and speed. Transients like Sukhvinder Singh's tabla on Ry Cooder's A Meeting by the River [Water Lily Acoustics 29] lacked in beat crispness. Mohan Bhatt's Indian slide guitar plucks were diminished in their crystallized bell-like rises in space. Everything was a bit softer and less distinct than I'm accustomed to. In short, I felt a few hairs short of cross-hair focus.
The speaker's softness wasn't to be shifted by ancillaries. Instinct might reach for wide-bandwidth transistors for leaner faster reflexes. One might gravitate to high power for more control if that culprit were suspected. It's after exhausting amplification options without a fundamental personality shift -- in my case the ModWright KWA-150, FirstWatt F5, AudioSector Patek SE, KR Audio 'Baby Kronzilla', Yamamoto A-09S and Ancient Audio Single Six monos -- that the time domain might suggest itself to those who did not suspect it sooner.



On that controversial subject, think me fully converted but libertine. From my first used pair of Vandy 2ces to the Meadowlark Shearwater HotRod, the Gallo Acoustics Reference 3.1, the various Zus, Rethm Saadhana and now ASI Tango R, I've mostly owned and loved minimum phase designs. Roy Johnson's Green Mountain Audio designs too fall into this category. They would be top personal targets if I needed another pair of dynamic speakers. But I'm also somewhat of a libertine because my older Avantgarde Duos weren't part of that school and the DeVore Fidelity Nines' crossover remains undisclosed. Very likely, theirs isn't a conventional 1st-order filter. Yet they don't sound off to me in beat fidelity so I can't be too religious about that whole 1st-order business. While my personal history shows a very clear bias, I wouldn't deny a speaker on principle just because it didn't conform. Of course this springs a trap for blaming steeper filter choices if one didn't warm to a speaker. So it's important to be careful. Preconceptions should not get in the way*.

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* The way I try to reconcile this is hierarchical. Certain more fundamental speaker basics need to be in place before the time domain asserts itself meaningfully. A crossover-less speaker could be so screechy and bass shy and generally ragged that its impulse fidelity is completely overshadowed by tonal balance errors and obvious response nonlinearities. But when the basics are in place, time domain improvements become viable.

I'll wrap this section by saying that I think it's time domain errors why clicks and clacks and plucks and noises here lack their innate charge; why everything seems subliminally packed in cotton and why the jump factor feels suppressed. Shifts in tonal balance, harmonic emphasis and even subjective transient speed by way of different amplifiers didn't touch this. Yet as soon as I returned to the leaner, far more transparent Tangos or the weightier denser Zus, that focus I was chasing instantly reset and percussive noises once again had that suchness I key into*.

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* It's important also to admit that Vandersteens, Thiels and Green Mountain Audio speakers all sound quite different from one another yet adhere to the same overall 1st-order concept. More current models perhaps excepted, the Vandersteens I owned were, just like the Blumenhofers, far more comfort oriented than the very precise and accurate GMAs I reviewed later. Phase coherence and subjective exactitude thus needn't be synonymous and a speaker can sound more laid back and cozy while still implementing time coherence.



Assessing Big Fun outside direct comparisons, there remains a particular hollowness (a kind of ringing or resonance) that occurs right in the presence region, i.e. inside the crossover window. It's most apparent on vocals. As you stand up, sit down and move your head up and down the vertical axis, its apparentness changes. But it's there. If you're sensitive to it, you'll wish for Windex to wipe down that fuzzy spot on the window. This covers the sonic particulars of this Blumenhofer model. How one responds depends on what one listens for. That's of course already the audiophile disease in action. It no longer listens to the music but instead, for specific sound effects.

While still in that frame of mind, I already mentioned how this speaker starting at €15.5K doesn't do 20/20. Below 40Hz, amplitude weakens. The $5,000/pr Zu Essence actually lasts a bit longer and with more weighty articulation. The aforementioned transient softness of the Blumenhofer operates equally into the lower reaches to be a coherent feature. Unlike hybrid design that marry different technologies to often suffer discontinuities of character, the Big Fun 20 is the same no matter where you take its measure.

In keeping with its name perhaps, the Big Fun 20 isn't about audiophilia nor its obsession with dissection and analysis. The overall level of resolution seems to have been deliberately toned down, the aforementioned focus softened to not emphasize the tendencies for separating out the whole into all of its ingredients. The upshot -- and now we segue neatly back to the beginning -- is that this speaker is custom-made for music not that well recorded. This covers much Pop and Rock and Punk and Dance. That's precisely the kind of thing one imagines Thomas Blumenhofer experienced live on location for so many years.



If you're into 'real' music like they play in your downtown clubs and not the old-fogey stuff whereby aging reviewers are often accused to miss the boat, the Big Fun 20 is perfect to get down and dirty with, not nasty and tiresome. That custom 8-incher sports a very stiff cone. Thomas brought a raw sample without attached spider, voice coil, dust cover or surround to make the point. It clearly goes very loud without losing its lunch and can't ever veer into metallic breakups by design. Nor is there a port to go huffing and chuffing. The tweeter is hornloaded to minimize excursion requirements. All these are preparations for SPL stability and an open invitation to rock out.

For this type of popular rather than audiophile-approved music, it's not infrasonics which matter. It's the 40-80Hz octave where the serious action occurs and which the Big Fun 20 has fully in its grip. Its gentle voicing will mellow Cyborg bass beats to sound less artificial. It won't shriek when the first e-guitar goes into massive overdrive distortion. Its toned-down attack sharpness will retain a modicum of naturalness even with robotic beats. It'll be a heckuva lot more fun than doing the deed with a ceramic blisterizer. That I believe is the project brief and raison d'ętre for this speaker.

Unless you have front-row season tickets to the symphony for 'nearer'-field transient sharpness, the Fun's somewhat remote voicing also fully applies to large-scale classical. When you compare live to playback sound -- the latter invariably compressed dynamically -- the audiophile attempt to simulate a visual facsimile in full 3D is very artificial. Perhaps because Thomas Blumenhofer knows this better than most, his speaker doesn't bother. Just think how the hyper resolution possible at home relies in no small part on the very low ambient noise we can manage. Compare that to the constant background din of a club or piano bar, never mind a rock concert. At home we're listening in an idealized bubble. Live sound is softer, rounder, more ambiguous than locked and far louder. If you nod in agreement, Blumenhofer's Big Fun 20 is one speaker that's got you squarely covered.

Tipping the scale
At €15.500/pr, Blumenhofer's Big Fun 20 doesn't lack for competitors. Most of those are toned and honed for greater reflexes and more chiseled physiques. Besides looking more a handcrafter's creation than big corporate, this speaker also sonically steps out of the mold to pursue something a bit more old-timey. It's a big friendly sound that goes loud without pain and seems tailor-made for Rockers young and old. Career audiophiles will want for more separation and resolution, Naimies for more acute PRaT. The Blumenhofer credo is about relaxation and bigger gestures. There are parallels to the Zu and WLM sound but both the Americans and Austrians pursue higher detail magnification, speed and incisive timing. Yet all three share an obvious aversion to the skinny modern hifi sound still en vogue today.



When Thomas Blumenhofer's site talks about the natural sound, he means something more amorphous, warmer and rounder. It's not about extreme holography or ribbon tweeter airs. It's not about sealed-box machine gun bass nor 3-inch midrange speed. It's about live sound eight to ten meters from the stage. Just because most audiophiles no longer reference reality does not mean Blumenhofer got it wrong. It simply means that not everyone will agree with him. Yet before one argues with a man who did live sound for a living for 30 long years, it might behoove us to refresh our memories. Still we might prefer to tailor our playback experience differently - it's ours after all to do as we see fit. It's simply also good to know just how we deliberately diverge because we mean to improve reality.
Blumenhofer does not. That puts him outside the mainstream, definitely. Whether that's a recipe for success remains to be seen. That those disillusioned by the mainstream just had an option added is clear already. Real, not copy-cat options are always good to have. Now put Blumenhofer Acoustics on that rather short list...

Quality of packing: Stout.
Reusability of packing: Multiple times.
Ease of unpacking/repacking: No particular issues.
Condition of component received: Perfect but veneer irregularities are to be expected and present.
Completeness of delivery: No issue.
Website comments: The Fun Series remains to be added.
Global distribution: Expanding. Inquire with maker
Human interactions: Responsive.
Pricing: On the high side.
Final comments & suggestions: Not completely full range in the bass, capable of very high levels without compression, medium resolution design. High-gloss lacquer options. As an experienced one-up guy, Thomas Blumenhofer remains exceptionally approachable on custom alterations or outright commissions. Tube electronics to come.
Blumenhofer Acoustics website

Srajan Ebaen




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