Gryphon Pendragon Reference Standard Loudspeaker System
An Exploration of the Complex Art of Simplicity
'Pendragon is a name historically associated with ancient kings of the Britons, most famously, Arthur of Camelot. The figurative title Pendragon or Pen Draig means head or chief dragon, symbolising the bearer’s uncontested leadership.'
As we launch the Gryphon Pendragon, the most ambitious reference loudspeaker system in the history of Gryphon Audio Designs, we feel that it is a fitting name.
Pendragon employs a further refinement of the self-powered bass tower made famous in its predecessor, the revolutionary Gryphon Poseidon system Pendragon pairs it with four Air Motion Transformer (AMT) drivers and a two-meter tall ribbon in an open baffle configuration for ideal coverage of an exceptionally wide frequency range extending from 16 Hz to 32 kHz.
Unlike compromised, “universal” amplifiers, the Pendragon bass amp has been conceived and built exclusively for optimal integration with the system’s custom-built drive units, rigid cabinet and flexible, user-adjustable room integration controls, for a level of performance unachievable by any standard mix-and-match approach.
The transparency, speed and spine-tingling musical realism of the resulting system set new standards for audio virtues such as resolution, timbre and soundstaging, illuminating the music in ways previously experienced only occasionally in glimpses or fragments of a speaker’s overall performance, but rarely in a true full-range system.
But before we get too deeply embroiled in the merits and technologies of the Pendragon, it is fitting that we pay homage to the Danish mathematician, inventor and audio theoretician who inspired Gryphon founder and CEO Flemming E. Rasmussen to introduce loudspeakers to the Gryphon portfolio.
When Flemming E. Rasmussen first contemplated expanding into loudspeaker design, it was a given that he would only do so, if he could offer a giant leap forward in musical realism, just as he had done previously to international acclaim in the fields of analogue electronics and digital front ends.
A serendipitous encounter with Steen Duelund quickly led to a “Eureka” moment for Rasmussen as he immediately recognised the true potential of Duelund’s wide-ranging theories once they could be harnessed and transformed into real-world products. Rasmussen knew instinctively that the Gryphon team possessed the requisite skills and experience.
Put simply, without Steen Duelund, there would be no Gryphon loudspeakers.
A Tribute to Steen Duelund
'Rasmussen and Duelund were kindred spirits and shared an admiration of purity and simplicity in problem solving.'
Loudspeaker design was Duelund’s all-consuming, lifelong passion and his high-flying theories were all founded in basic principles of mathematics, physics and psycho-acoustics, supported by empirical evidence.
Above all, there was stringency to his thinking. If he felt that a theory had merit, he would test it for himself and formulate his own conclusions. If he found a principle to be correct, then it was adhered to without deviation or compromise.
Despite Duelund’s mathematical background, he eschewed complexity in problem solving. Like Rasmussen, he firmly believed that the basics of electronics only require a few parts, but because available parts are usually far from perfect, a huge number of additional components are required for damage control or, in Rasmussen and Duelund’s favourite phrase, disaster management.
It is a perplexing paradox that it is a far more demanding task to create a simple, near ideal circuit than a complex circuitry with ten times as many components.
Because Duelund’s extensive experience had revealed that drive units typically suffer from major shortcomings that require numerous corrective components (disaster management), he set out to find the ideal driver that required little or no correction to do its assigned job.
Duelund’s first projects in the 1960’s involved massive full-range horn systems arising from a fascination with what the total absence of crossover components could contribute in terms of purity, transparency and dynamics.
Finding fault with even the most costly so-called full-range drivers, Duelund began to experiment with crossover networks, ultimately developing what he dubbed the synchronous crossover, an ideal filter with overall flat frequency response and no phase shift.
Most crucially, Duelund discovered that each driver in a multi-way system must have identical phase shift, i.e. there must be no phase difference between the divers, regardless of frequency.
That the relative phase difference between drivers is more important than overall system phase also makes intuitive sense in light of the fact that the human ear uses phase to determine the directionality of sound, unlike a laboratory microphone.
With a breakthrough, ideal real-world filter, the major task remained of finding the best available drivers and then modifying them heavily to ensure that filtered driver response followed the filter function. In Duelund’s perfectionist hands, filtered driver behaviour had to be perfect across as broad a frequency range as possible, not just to the -6 or -10 dB point, but all the way down to -30 dB.
Once these extensive modifications were completed, a new universe of loudspeaker design opened up.
Duelund recognised the same attitude in Rasmussen’s approach to electronics development and they collaborated on radical experiments with little commercial potential, but acquiring valuable knowledge in the process.
The true legacy of Steen Duelund, beyond his innovative crossover design, his mathematical papers and the drivers, capacitors, resistors and coils he constructed, lies in his unique approach to solving problems, his lateral thinking and his openness to new ideas.
It is this heritage that lives on in Gryphon loudspeakers.
Steen Duelund’s passing was a great loss, but thanks to years of close collaboration on decades of Gryphon loudspeaker development and comprehensive written documentation of his theories, there can be no doubt that Gryphon loudspeakers, from the Pendragon and on into the future will continue to be developed in his spirit.
'Everything should be made as simple as possible, but not simpler.'
There is no escaping the fact that no single drive unit is capable of properly reproducing the entire audible range from 20 Hz to 20 kHz. No diaphragm can move fast enough to reproduce 20 kHz overtones and, at the same time, move enough air to reproduce deep bass at concert hall levels.
For this reason, loudspeaker manufacturers devote considerable resources during product development to selecting specialised drivers for each frequency section and, more importantly, to designing a crossover network to coerce them all to work together. To do so, the frequency spectrum is sliced up electronically and each piece is directed to the appropriate driver where things are hopefully reassembled acoustically.
It is at this point that so much can go wrong.
Are the selected crossover components good enough to do their job without signal loss or distortion? Are the drivers sufficiently similar in tonal quality and speed that they can create the illusion of a single coherent source of sound? Does the crossover properly compensate for the drivers’ varying sensitivities so that the resulting sound is correctly balanced top to bottom? Have the crossover points between the drivers been properly tuned for undetectable, seamless transitions with no frequency dips or peaks? Is the cabinet designed to prevent resonances and deleterious interaction between the drivers? And don’t get us started on phase relationships…
As proven time and again, Gryphon Audio Designs are masters of this arcane art, but it has always been one of our guiding principles that eliminating a problem is far better than trying to solve it.
First off, Gryphon Pendragon eliminates the cabinet altogether in the mid/high frequency range. Instead, an extremely rigid panel houses a vertical array of four Air Motion Transformer (AMT) super-tweeters alongside a single, two meter tall dipolar planar magnetic thin-film ribbon transducer.
With ideal sound reproduction and mechanical behaviour across more than seven octaves from 200 Hz to 18 kHz, the Gryphon Pendragon ribbon eliminates multiple crossover filter sections in the critical mid frequency range, preserving spectral and temporal integrity.
The 200 Hz crossover consists of the finest Duelund parts and solid silver components encased in a heavily damped aluminium block suspended freely behind the panels. At the extreme high frequency transition between the ribbon and the AMT super-tweeter array, the ribbon rolls off naturally with no lowpass filter section in the signal path.
The high frequency system’s innate wide and even horizontal dispersion with virtually nil vertical dispersion creates a large, stable sweet spot with none of the floor and ceiling reflections that muddy the sound of conventional multi-way systems. Eliminating this major source of room interference allows Gryphon Pendragon to achieve new levels of room-independent clarity and resolution.
By eliminating fundamental issues of mass, inertia and internal resonance, the Gryphon Pendragon ribbon and AMT drivers are able to respond accurately and instantaneously to even the subtlest of micro-dynamic changes, conveying all the expressiveness, richness and complex textures of the greatest recordings, laid out across a vast, natural soundstage with pinpoint stereo imaging.
The Pendragon high frequency panel offers unrivalled transparency and resolution that deserve to be mated with the finest amplification and source components.
Thanks to its line source dispersion characteristics, the Pendragon ribbon generates a continuous, perfectly coupled, cylindrical wavefront across its entire frequency range for a uniquely coherent, wide and deep soundfield.
As a consequence of this ideal wavefront form, sound pressure level at a given distance drops off by only -3 dB, half the rate of conventional speakers (-6 dB), for a more full-bodied, consistent, room-filling listening experience.
The ribbon is mounted in a three-layer frame of heavy-gauge, self-reinforced steel to ensure solid construction, free from any inherent resonance. A symmetrical magnet system consisting of a push-pull configuration of ceramic magnets fitted on both sides of the diaphragm provide linear drive of the diaphragm whose moving mass is actually less than the air load.
Laminated with aluminium strips that act as a planar spiral voice coil, the ribbon’s large radiating area moves only a very small distance even at high volume with minimal distortion and perfect control. Due to the ribbon’s open construction and large surface area, heat dissipation is not an issue, resulting in high power handling capabilities with consummate ease.
The AMT Array
The extreme high-frequency range is handled by an array of four extraordinary Air Motion Transformers that move air by driving an extremely low-mass folded sheet in a semi-perpendicular motion via a powerful magnetic field. Following extensive research into materials and diaphragm geometry, the Pendragon AMT employs a heat-resistant Kapton film base, aluminium conductor traces and an innovative fold geometry.
Because of their large surface area and pleated structure, the Air Motion Transformers move a large air volume with minimal diaphragm motion for lightning fast transients with flat frequency response well beyond the audible range with negligible distortion and a total absence of compression.
The AMT array incorporates a +1 dB attenuator for ideal integration with the acoustics of the listening space.