ARCHITECTURAL RIBBON LOUDSPEAKERS™

The first loudspeaker I ever built with a ribbon tweeter was in 1984. This was the Foster E110 ribbon from Japan, a great little tweeter with sparkling highs that went on forever. I will never forget its clarity and it was also through the E110 that I began to clearly hear the differences in crossover component quality, particularly capacitors and resistors.

Two years later I built a ribbon tweeter of my own, using aircraft grade aluminum foil and samarium cobalt magnets and a transformer salvaged from the Virginia Tech Physics Department's electronics room. It was a fine sounding ribbon and I enjoyed it so much that the following summer, while driving delivery trucks for my father's ice cream factory, I saved my money and that fall purchased my first pair of "sort of" ribbon speakers, Magneplaner 1B's. These were set up in my graduate student apartment and my roommates and I would endlessly compare them to whatever cone-and-dome speaker I was building at the time.

I finally had the sell the Maggies in 1998 to raise money for plane fare to Boston to interview for my first job with Acoustic Research (AR), and while I missed them I had built better speakers by that time (loudspeaker designers always say this of thier own designs). I also had the pleasure of borrowing some very good speakers, including the ProAc Super Tablettes, original Quad Electrostatics and the Celestion SL700's.

Part of my responsibilities at AR was to evaluate and choose among crossover component manufacturers that would build our crossovers as wall as those loudspeakers we were manufacturing for others under their private labels.

All of this made me uniquely suited for my next job, as a ribbon and crossover designer for Apogee Acoustics. Those that remember Apogee usually do so with fond respect, as Apogee was a visionary company that produced what was widely considered among the two or three best sounding, and most visually stunning, loudspeakers of their day. Apogee not only had an active ribbon transducer development program, it also had an active crossover component development program. Apogee made their own inductors and had their own capacitors, resistors, internal wiring and binding posts custom built.

In 1992 I started North Creek Music Systems, originally as a loudspeaker component and kit distributor and finished loudspeaker manufacturer, and from the beginning we had an active program in crossover component evaluation. It was largely through this program that audiophile-grade resistors came about (first through Ohmite and then the North brand, now there are many), and high voltage film-and-foil capacitors and large gauge wire wound inductors became the components of choice with many high end loudspeaker companies. By year 2000, North Creek supplied over one hundred manufacturers world wide with some or all of the crossover components.

North Creek was also a US Distributor for ribbon manufacturer Aurum Cantus, and made some ribbon loudspeakers under the North brand throughout the first decade of the 21^st century, including the North Manifest at left.

I still had a pair of Apogee Stage loudspeakers, a parting gift from Jason Bloom when I left Apogee, which my girlfriend Hilary enjoyed in her listening room for several years. . The original Stage was a great little loudspeaker, punchy and musical and with that stupendous Apogee sound stage. Going from my listening room, with mostly cone-and-dome monopole loudspeakers, to hers, with full range dipole ribbons, was always a bit of a shocker. My listening preferences had changed, and I had grown to prefer the precise imaging and back-drop sound stage of the North loudspeakers to the more diffuse presentation of the Apogees. I could also clearly hear how dated the Apogee crossover components had become, and I missed the listening position freedom that one has with a North loudspeaker.

It was a trend in loudspeaker design from the mid 1980's through the end of the 1990's to concentrate on a large sound stage and precise image focus. The goal was to bring the performance one step closer to the listener and the listener one step closer to the performance with only two channels, to create a more convincing illusion so that one's mind could more easily make the leap into believing that they were actually there. Part of doing so was to create a soundstage that was larger than life.

Of course, dipole sound stage is not real or accurate, and in fact it is always enormous even when it's not there in the recording. This is true not only of ribbons but also of electrostatic, magnetostatics and all other dipole loudspeakers. The Apogee sound stage is an artifact of the loudspeaker design. I am not saying this is a bad thing at all, and in fact among the reasons I love all of my Apogee's so much is because of the enormity of their sound stage. But.... technically.... it still is distortion.

All classical ribbon, electrostatic and planer magnetic loudspeakers have an Achilles' heal, and that was the "head in a vice effect". In fact, with the Stage's, the vice is in both the vertical and horizontal direction ("the head in two vices effect?") If one was not perfectly centered between the Stages, and at the exact mid-height of the tweeter ribbon, the sound was heavy through the midrange and the top end was completely gone. The Stage was an audiophile speaker, designed for only one listener at a time.

In 2002 I decided that North Creek should make a crossover upgrade for the Apogee Stage, not just an update but also an effort to improve it all around. The North Creek crossover upgrade solved the horizontal vice issue; that is, listeners can easily sit three abreast and have great sound. The vertical vice is intrinsic to pre-Sweet Field™ ribbon design, it could not be helped. The 21^st century crossover components are much clearer, sweeter and more dynamic than their older counterparts. The upgraded Stage simply blows away the original. North Creek began manufacturing the Apogee Stage Upgrade in May 2002.

Later in 2002 I decided it was time to build a new kind of ribbon. Among the goals was to build a loudspeaker that had the same magical Apogee-style sound stage, but to also eliminate the "head in two vices" effect. It took years of working with the ribbon midrange/tweeter to come up with a substantially superior design, and it really wasn't until 2005 that we really had everything working perfectly, and applied for the patent on the Sweet Field™ technology. This became thee Advanced Ribbon Technologies' Metro loudspeaker, a two-channel speaker which equaled the upgraded Stage in sound stage, clarity, and musicality, was much more transparent and far superior in dynamics. And both vices were eliminated. The Metro was in production from 2005 though 2009.

By then Hilary and I had installed in-wall home theater loudspeakers in my living room, which other than an occasional glance at CNN or Link TV sees use only for watching Virginia Tech Football. I can not deny the convenience of in-wall loudspeakers, so the next step was to built the Metro ribbon into the wall and see what would happen. The first thing I discovered is that we could extend its bandwidth, and with very careful in-wall cabinet design, high pass filter/protection circuitry design, and the original Sweet Field™ ribbon shape, we had a very listenable in-wall speaker from about 135Hz to beyond 30kHz. This alone was a small breakthrough, as crossoverless performance from almost an octave below middle C to well beyond the threshold of audibility from a line source had never before been accomplished, and it was just magical. A ribbon's clarity over so wide a band width is so far superior to any other kind of loudspeaker, it is uncanny how it can draw one in.

But the original Metro ribbon in-wall had some issues. The biggest problem was that in taking the ribbon from the Metro's 351Hz crossover frequency an octave and a half lower, we increased its power consumption by a factor of six. This meant the ribbon would get six times as hot, and in fact we could play them so hot that one could see heat ripples emanating from the ribbons' surface. It does not damage the ribbon, but it was more than a little unnerving.

Then there was the listening window. The original Sweet Field™ had two listening windows, one at about the mid-point of the ribbon and then a second, larger field above about the top third. This was fine for the Metro, as it was also an audiophile product, but my goal was to create a uniform listening window the entire height of the ribbon.

One's instincts say that one should just make the ribbon in a long, semicircular arc, and that would expand the listening window. But it doesn't work (and in fact, it was known way back in the 1960's that this approach does not work). So I started there anyway, and by forcing the ribbon into differently shaped arcs, making measurements, changing the arc, and making more measurements, I was eventually able to create an arc that produced the optimum radiation pattern - a uniform sound field the entire height of the ribbon.

When I documented the shape, and then took the ribbon apart and stated documenting the arc, the pattern began to emerge. One does not need to work in acoustics for long before one sees Fibonacci sequences in everything, and North Creek had built cabinets with aperiodic bracing based on Fibonacci's ratios since the early 1990's. My listening room ceiling is covered with quadratic diffusers based on a Fibonacci sequence. So it took me almost 30 seconds to realize that the ribbon worked optimally in a Fibonacci Arc™, and the Fibonacci Transducer™ was born. We called them the Fibonacci Gen 1.

Still, at 28 inches the ribbon was not long enough, and the Sweet Field™ was only about two feet tall. The window needs to be about 40 inches to cover both the lowest seating position and the highest standing position.... so I built some 45 inch ribbon frames and went to work. The 45 inch ribbon frame with the ribbon formed into the optimal Fibonacci Arc™ had the perfect Sweet Field™ radiation pattern, a 42 inch tall window (1.1 meters) with absolutely perfect listening characteristics... and it sounded wonderful. The natural transparency of a ribbon and - because they were long enough - and absence of floor and ceiling reflections, a low end limit of 100 Hz, we had seamless, crossoverless performance throughout the entire range a human voice and most instruments. A unique, continuous sound quality I had never heard anything quite like before. This was the Fibonacci 1.1 Gen II.

At low volumes the Gen II's worked beautifully, but because we had extended the bandwidth even lower we had more heat to deal with, and at high volumes the Gen II's would get pretty hot. With ribbon loudspeakers, efficiency is proportional to the square of the magnetic field. So our next step was to exchange the ceramic magnets for rare Earth. We went with Neodymium, which are eight times stronger than ceramic and about ten times more costly.

This brought about the Fibonacci 1.1 Gen III. This was a spectacular sounding loudspeaker, with unprecedented speed and microdynamics and layers and layers of detail. Full bandwidth (100Hz to beyond 30kHz), extremely efficient (16dB more efficient than the Gen II's!), easy to install, and a dream for most amplifiers to drive. The sound was just riveting. We were awarded another patent and went into production of the Fibonacci 1.1 Gen III's in March of 2008, whence they debuted at the Montreal Festival du Son.

I do not get a lot of chances to listen to other loudspeakers, so whenever I get to an audio show I take every chance to get out and around and try to hear everything. The 2008 Festival du Son in Montreal was a great show (and my favorite city in North America), and I heard some very good loudspeakers, many of which I could easily live with. But none had the unique combination of continuity and clarity of the Fibonacci 1.1 Gen III's. Many of the attendees felt the same way, and our room was full of listeners almost the entire time and many came back several times for another listen, and we were told by several that we had the best sound at the show, and we made some sales. A great debut for the 1.1's.

I also have a good memory for how different speakers sound, and I remembered an afternoon in 1991 in the Apogee listening room, sitting with the late Jason Bloom, as we listened to the Stages, then the Apogee Duetta Signatures with the original passive crossover and a prototype of the DAX. The Duetta Signatures were beautiful sounding loudspeakers, widely felt to be the best money could buy throughout the 1990's. Much richer and more dynamic than the Stages, if only because of their size. Jason and I were comparing the stock, passive crossover to the active DAX crossover, and we both kept coming to the conclusion that the passive crossover just sounded better. Finally, Jason said to me, "that Duetta crossover, it is just perfect!" and I agreed. I don't know who designed it, but whomever did was really really good. The DAX prototype went back to design. Not many speakers have given me an impression that lasting (almost 20 years!) so the summer of 2008 I did what any other ribbon loudspeaker manufacturer would do... I searched and searched and finally found and bought a perfect right Duetta Signature in New Hampshire and a perfect left Duetta Signature on Long Island.

I set them up in the North Creek listening room, the upgraded Stages on one wall, the Duettas on a second, and the Fibonacci 1.1 Gen 3's built into the third. Identical CD players, amplification by Belles, identical speaker cables, only the pre-amps and interconnects were different. Everything warmed up for days. The Duetta Signatures are absolutely wonderful loudspeakers, and I could gladly live with them. They are beautifully voiced, have slammin' deep bass, a luscious midrange and a smooth, soft, extended top end. But it was no contest. The upgraded Stages were so much better than the Duettas, and the Fibonacci 1.1 Gen 3's were so much better than the Stages, that I knew we had a real winner. The Fibonacci 1.1 Gen 3's were the real deal.

Still, in the back of mind I felt the product could be improved. The Fibonacci Gen 3's are a home theater loudspeaker, and will always be used with a subwoofer. Most home theater processors' built in subwoofer crossover frequency is 80Hz, and most good subwoofers can go up to 80Hz with reasonable speed. The low end limit of the Fibonacci Gen III's was 100Hz. Even the best subwoofers are far happier at 80Hz than 100.

So in early 2009, when time allowed, I began trying different ways to extend ribbons' low end. Simulations of a new motor structure, redesigning the ribbon diaphragm, building and rebuilding prototypes, scribbling ideas on napkins, yellow pads and on one occasion my golf scorecard. As winter fell in October 2009 the new ribbon was getting pretty good, a center channel had sprung up, and I was giving demos to friends, family, any anyone else who cared to listen. We made more improvements in the diaphragm and protection circuitry. By February 2010 we had it. A slightly larger ribbon, with a more powerful, more linear motor structure, higher excursion, higher efficiency, and higher power handling.

This is our "in-wall" display unit, which we have shown at CEDIA and RMAF and most recently at the Capital AudioFest. It is actually a portable wall-and-table-top, with the Gen 3.1's in 16-inch-on-center cabinets left and right and the Gen 3.1 Center Channel mounted below the 56-inch video screen. At over three inches wide and 22 inches tall the Gen 3.1 Center Channel is actually the second largest ribbon ever made (we custom built a three inch wide, seven foot tall pair for a very large installation). Conventional subwoofers are mounted below the left and right speakers. The entire display is six-foot-three tall and just under eight feet wide.

We had wonderful sound at the Capital Audiofest. It was one of those shows where we could play anything - Rock, Jazz, Classical, even my treasured Mobile Fidelity gold CD of Pink Floyd "The Wall" - and the sound was just fantastic. 5.1 was mesmerizing. Shown here is Diana Krall "Live in Rio" on Blue Ray, and her spectacular piano work was absolutely convincing. The same comment we kept hearing was "the clarity"..."the clarity"... and it is true. The fact is that our ribbons are generations closer to the original performance than any other kind of loudspeaker, and it really makes a difference. Many people felt it was the best sound they had ever heard, other than live. More photos here.

So..... what did we do for surround speakers? Well, here they are! The new Fibonacci Technologies' Vaya! Ribbon Tower Monitors. These are beautiful floor standing tower loudspeakers in an acoustically optimized oval cabinet, built with the Fibonacci 1.1 Gen 3.1 transducer with full protection circuitry. They can be Near Wall Specific™ with a touch of rake angle for use as surround applications or high SAF (Spouse Acceptance Factor) installations, or they can be placed in free field with the flick of a switch and become the most stunning free field loudspeakers ever made.

The Fibonacci Technologies™ Gen 3.1 is the holy grail of home theater loudspeakers. It comers the entire range uniformly, flawlessly, seamlessly, which a sense of natural musicality and harmonic continuity that is unsurpassed. There is nothing really quite like it. It is simply the most transparent, dynamic, smoothest, clearest loudspeaker transducer ever made.

My business partner, who occasionally proof reads our literature but does not write any of it, says I have a "penchant for understatement." He is probably right... and saying the Fibonacci 1.1 Gen 3.1's are "the real deal" is a significant understatement. The Fibonacci 1.1 Gen 3.1's are actually a revolutionary product. Every single limitation, draw back, and compromise of all historical loudspeaker transducers has been addressed and eliminated. They are, simply put, a revolutionary new type of loudspeaker. We can't wait for the world to hear them.!

Rocky Mountain Audiofest, October 14-17, 2010, Denver, CO.

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All Fibonacci Technologies™ ribbon loudspeakers are designed by George Short. George began building loudspeakers in his early teens in Rochester, NY. He built his first ribbon transducer in 1985 while an undergraduate at Virginia Tech, where he received a Bachelor's of Science in Physics in 1986. Following a two year independent study of electroacoustics and for the successful defense of his Master's Thesis, The Aperiodically Damped Loudspeaker System, he was awarded a Master's of Science in Applied Physics (Electoacoustics), also from Virginia Tech.

George began his professional career with Acoustic Research (AR), then the world's fifth largest loudspeaker manufacturer. His responsibilities included basic research in cabinet and cone construction, crossover design, and fundamental listening evaluation of drivers and crossover components.

In 1990 George joined the engineering team of Apogee Acoustics. Apogee was and remains history's only full range ribbon loudspeaker manufacturer, and considered among the most respected loudspeaker companies of their day. Throughout the 1990's, virtually every loudspeaker made by Apogee could be found among Stereophile Magazine's Recommended Components. George did both crossover and ribbon design for Apogee. 

In 1992, George founded North Creek Music Systems, a company dedicated to the advancement of the science of loudspeaker crossover component technology. North Creek was the first company to promote the use of military grade electronic components in crossover applications, developed several new technologies specific to high performance crossover manufacturing, was among the earliest distributors of Scan-Speak in the United States, and is quite possibly the only company in history to design a family of crossover components by ear specifically for high end audio applications.

George founded North Acoustics in 2001, a company dedicated to employing the most advanced drivers, crossover components, cabinet technologies and manufacturing methods to design and produce the world's finest conventional loudspeaker systems. The North Acoustics' Spirit and Kitty Kat Near Wall Specific™ Loudspeakers offer exceptional performance in the most highly favored SAF environment.

Evolving from the North Acoustics family of finished loudspeakers and North Creek Music Systems' ability to manufacture delicate but complex instruments came the classical .A.R.T. ribbon transducers and the revolutionary Fibonacci Ribbon Transducer™.

"We believe that enduring quality is the most significant virtue of any product ™" - George E. Short III, 1992

The entire Fibonacci Technologies' product family will be on display at the Rocky Mountain Audiofest, October 14-178, 2010, Denver, CO.

Info@NorthCreekMusic.com

 This publication is copyright © 2008, 2009, 2010 by North Creek Music Systems, Inc. All rights reserved.

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