Design Considerations - from lute to violin
The shape of the lute inspired the Guarneri. This form is how Sonus faber conceived and realized a highly musical compact monitor to be as close as possible to an acoustic point-source. The shape of the lute also inspired the Amati. Additionally, increasing the radiation area and increasing the extension of the lower frequency spectrum achieved the proper reproduction of full-scale orchestral scores in a more lifelike and believable scale. Moving forward to reproduce a new kind of musical stimuli, much research for Stradivari was focused on the study of the acoustic source in an infinite plane. Just as the radiation of sound from the violin’s “piano armonico” (harmonic plane) is projected so is the sound from Stradivari. By consequence, if the lute inspired Guarneri and Amati, the Stradivari is by the violin.
A three-way design in a unique elliptical enclosure featuring 2pi radiation and a symbiotic tuning system. Each driver is loaded into a tunable cavity, open in the case of the midrange and low frequency drive units, sealed for the high frequency unit. The crossover employed has been developed not only for purity of transition but specifically for enhancing the performance of the amplifier/loudspeaker interface.
Main Acoustic Enclosure
With the Stradivari the acoustic property of the driver/cabinet interaction has been brought close to theoretical perfection. The curved external walls are constructed using multiple layers of wood with damping inserts placed between adjacent structural layers. Each wood layer is quality-graded and carefully oriented by density and grain for optimized performance and appearance. Additionally, a special sub-structure of reinforcing ribs is incorporated internally to virtually eliminate any spurious vibrations. The result is an enclosure of exceptional beauty and stiffness, free from undesirable resonances and coloration. By dedicating this project to Stradivari, we could not avoid addressing one of the most famous and mysterious secrets of the great Maestro — the lacquer finish. Great care was taken to find a process that appears both unique and original, air permeable and respectful to the character of the wood. Interestingly enough, this precious lacquer process is quite supportive to the acoustic nature of the speakers sound.
High Frequency Spectrum
The 1.25 in. (33mm) silk ring radiator employed is simply the finest version available from this family of drive units. Compared to metal membrane versions they exhibit a far broader bandwidth and wider dispersion while maintaining the inherent advantages over traditional dome shaped diaphragms. A carefully controlled frontal radiation pattern from the dual-wave diaphragm is due to a proprietary dual-toroidal wave-guide. This wave-guide, inspired by the concentric ripples generated by a drop falling on a still water surface, harmonically integrates the radiating diaphragm into the curved, virtually infinite, front baffle. The back wave of the diaphragm is loaded into a crafted wooden acoustic labyrinth, eliminating any unwanted reflections and colorations. Wood was chosen for it superior damping qualities when compared to either metal or plastic.
Mid Frequency Spectrum
A 6 in. (150mm) transducer was chosen for its extremely high dynamic linearity and many other qualities traditional to Sonus faber. The midrange spectrum is in fact the “soul” of the Stradivari system. Special care was taken to create absolute synergism between the character of the high frequency radiator and the electro-acoustic properties of the mid frequency driver. Inspiration came from the “Anima”, a little known device found within a violin. The Anima is what connects the top surface of the violin’s body to the bottom surface and without it; a violin simply would not be a violin! Internal to the Stradivari enclosure is a cardioid-shaped chamber that controls and dampens the reflections to the rear of the transducers cone. Its walls are “compression-held” by the front and rear of the outer structure and much like the “Anima”, it controls mechanical resonances for the most uncolored musical reproduction.
Low Frequency Spectrum
The dual 10 in. (260mm) drivers that comprise the low frequency system of the Stradivari employ cones made from an exotic aluminum/magnesium alloy that exhibits a great stiffness to weight ratio. These cones are treated with an elastic coating to further prevent any residual coloration. Additionally, a natural rubber surround delivers an optimal mechanical termination that allows for extra long cone excursion. Wooden coaxial anti-compressors remove any cavity compression effects and assists in the ventilation of the voice-coil, providing effortless low frequency extension. To avoid any mechanical modulation these drivers are housed in a tuned volume within the enclosure, isolated and decoupled from the mid and high frequency units by this separate sub-baffle. The transducers, within this properly loaded acoustical environment, are capable of true pistonic action and extraordinarily accurate mechanical behavior.
The basic design approach incorporates both a multi-slope circuit topology and thoughtful control of both amplitude and phase over the entire musical spectrum. The chosen crossover transition frequencies are at the boundaries of the human voice spectrum, roughly 300Hz and 4,000Hz. Since the vast majority of acoustical musical instruments have their fundamentals below 4,000Hz, this transition point is the most seamless and least disruptive to musical harmonics. Another special aspect of the crossover design is the unique implementation of the filter structure that controls component micro-phonics and last but not least, the nature of the conductor in the signal path. To prevent harmful vibrations for affecting the integrity of the sound, the crossover is completely cast within a vibration inhibiting resin material. Additionally, the signal path from the crossover is enhanced by the use of a connection terminal made from a precious alloy of silver and palladium. Developed specially for this application and based on concepts of nanotechnology.
|System Type:||Three-way elliptical design with virtual 2pi radiation and symbiotic tuning system|
|Acoustic Enclosure:||Multi-layered, constructively damped elliptically shaped enclosure formed using hand-selected wood layers, quality-graded, and oriented for optimized resonance control. Sub-structural ribs strategically placed for absolute rejection of spurious vibrations.|
|High Frequency Spectrum:||1.25 in. (33mm) ultra-dynamic and linear Neodymium ring radiator with exclusive dual-toroidal wave-guide. Natural wood acoustic labyrinth rear chamber with mechanical anti-resonator synergistically designed and integrated.|
|Mid Frequency Spectrum:||6 in. (150mm) ultra-linear drive unit. CCAW / Kapton and eddy current free voice coil. Dynamically linear magnetic field motor incorporating Kellog and Faraday rings. All moving elements optimally ventilated for resonance free response. Designed synergistically with its vented chamber. |
|Low Frequency Spectrum:||Dual 10 in. (260mm) lightweight aluminum/magnesium alloy cone drivers in an acoustically amorphous vented chamber. Dual Faraday copper ring long-throw motor system with 2pi eddy current free voice coil for ultra dynamic performance and linearity. Coaxial anti-compressors made of wood are employed to remove cavity resonance and distortions.|
|Crossover:||Special multi-slope circuit topology with optimized phase/amplitude response. Crossover points at 300Hz and 4kHz. Terminals and wiring use silver/palladium alloy with “nanotechnical” structure. |
|Sensitivity:||92dB, 1W/1m |
|Nominal Impedance:||4 ohms|
|Power Handling:||Minimum amplifier 30W, Maximum Amplifier 300W without clipping.|
|Frequency Response:||22Hz - 40kHz|
|Dimensions:||650 x 500 x 1360mm (WDH)|
25.6 x 19.7 x 53.5 in. (WDH)
|Weight:||150 Kg/pair - 330.7 lbs/pair without packing|
195 Kg/pair - 429.9 lbs/pair shipping wieight