Handcrafted Designs Bringing Imagination To Life!

Sason Ltd.

The World's First Full Range Stand Mounted Granite Reference Monitor

 

 FreeEnergy™

The FreeEnergyTM concept is based on the Conservation of Energy principle of physics which states that energy cannot be created nor destroyed, only transformed. As it applies to a loudspeaker, amplifier power should not be transformed into losses within three properties of a loudspeaker system:

 

·    Electrical. The complete electrical system within the loudspeaker and its various wires, connections, and driver motor systems.

 

·        Mechanical. The efficiency of all the "working elements" and their physical properties as relates to rigidity and structural strength.

 

·        Acoustical. All items about the loudspeaker that affect proper control of the sound waves such as diffraction, dispersion and sound related to the enclosure internal volume and material.

FreeEnergyTM is about eliminating any transformation of the amplifier energy that alters or corrupts the amplifier output and allows the amplifier to meet its maximum performance capability. The Sason Ltd high performance loudspeaker with FreeEnergyTM delivers all the music unchanged and undamaged, fully preserved and true to the source. It is a difference in the sound of the Sason Ltd from other Class A speakers that is unmistakably "right" from the first musical note.

A deceptively simple concept upon first examination, you might assume these three critical loudspeaker properties would be mastered by other manufacturers producing a World Class transducer, but as you search for another loudspeaker that matches Sason Ltd in every facet, it will become obvious there is no other. Every detail has been obsessively evaluated and costly methods and materials are utilized only if they raise the performance bar to another level. Nothing in the Sason Ltd is taken for granted and conveyed to the listener as the newest fashionable idea or contrived as a status symbol.

As the designer of the Sason Ltd granite loudspeaker, Steve Rothermel had simply wanted to satisfy his search for a transducer capable of meeting the goal of eliminating those losses or corruptions of the amplifier signal at each of the three elements within a loudspeaker system: Electrical, Mechanical, and Acoustical. Meanwhile, Ridge Street Audio Designs was beginning to blossom and the need for an accurate in-house evaluation tool existed. Not having satisfied a long search to meet his uncompromising standards, Steve decided to begin development of his own loudspeaker and also satisfy RSAD's demanding requirements. After three years and thousands of dollars spent on research and development, along with invaluable input from long time associate Robert C. Schult, founder of Ridge Street Audio Designs, the Sason Ltd was born.

You are invited to see side by side comparisons listed below of the FreeEnergyTM vs. Conventional loudspeakers (representative of "flagship" or "state of the art"), within each of the three key elements. While some loudspeaker designs may meet certain individual features listed here, Ridge Street Audio Designs is highly confident the Sason Ltd granite loudspeaker is unique and outstanding in the final analysis. There simply is no equal, born out of the passion to pursue music in its purest, original form.

 

Electrical

FreeEnergyTM

Conventional


Pure Direct ConnectTM Eliminates the binding post as a signal conductor. Your speaker cable connects directly to the crossover internal wiring for a loss-free signal path.

Even the dearest binding post cannot best a direct connection between the speaker cabling and crossover leads. The binding post is an additional conductor with an additional connection point. The delicate music signal is compromised by this unnecessary hardware.

All internal wiring using Ridge Street Audio Designs ExLGIITM solid conductor high-purity silver. Handcrafted and impedance matched for optimized signal transfer. The goal is to adhere to a consistent impedance value throughout the loudspeaker system. Impedance takes into account the combined components of resistance, capacitance, and inductance. As small as the impedance changes may seem to be, caused by the internal wiring of a loudspeaker, they do influence the overall sonic character of the system. Additionally, organic low-dielectric insulators to protect fine audio details and the for most natural sound.

Many flagship loudspeakers models do not take into consideration the complex impedance of the internal wiring and how it relates to preserving the amplifier signal. Mass-produced multi-strand copper wiring is commonly used. Multi-strand wiring is susceptible to mechanical vibrations between the individual strands. Resonances are introduced by these vibrations and translate into audible signal noise. This is heard as a lack of clarity, usually in the upper frequencies, and "smearing" of the sonic image or a lack of precise focus on individual musical instruments.

Ridge Street Audio 7" MidWoofer from modified Scan-Speak Kevlar® unit features higher motor strength than raw factory unit and an extremely low inductance system with the SD1 motor system for superb amplifier control and efficiency. Superb control for extreme broadband clarity and stable frequency response balance at all volume levels and under dynamic conditions. Some modifications proprietary to Ridge Street Audio Designs.

No comparable design available! Other high-end midwoofers lack complete motor control at excursion limits and feature higher inductance. Loss: Micro detail is lost, shifts in tonal balance at higher volume levels, bass and midrange is veiled, "slower" sound and mismatched sound character when partnered to the high frequency unit. New, "revolutionary" drive units in the market place compromise overall efficiency, sound "slow", display shifts in tonal balance at different volume levels or do not represent realistic and natural sound character especially at lower volume levels.

All electrical connections including to the drivers are direct-soldered and utilize high silver-content solder, bypassing the need for push-on connectors that introduce losses in the signal chain.

Utilizes push-on terminals or other quick-connect terminals. Loss: The use of quick-connect terminals loses signal information and adds resistance. Impedance matching in the signal cabling is compromised. Micro details get lost or become "colored". Added resistance impacts amplifier efficiency and control.

Printed Circuit Boards are not used anywhere within the Sason Ltd. All connections are direct connected component to component.

PCB's are utilized. Loss: Compromised signal integrity by introducing unnecessary terminations and additional dielectrics from the PCB materials and signal paths.

Ridge Street Audio 1" hand coated silk dome Tweeter features higher motor strength than any comparable unit from Scan-Speak. A highly unusual design feature is the Faraday copper sleeve around the pole piece, lowering self-inductance and electrical Q, especially under high excursion limits. This is the first Tweeter we have found to feature a Faraday sleeve. The Faraday sleeve helps maintain temperature control at the operating limits by significantly lowering distortion, which affects the efficiency of the amplifier's control of the motor system.

No comparable design available! Even the best metal or silk dome tweeters do not feature the motor system control efficiency of the Sason's Tweeter. Loss: Lack of motor power and magnetic flux distribution area eliminates low-level harmonic detail and realism at high volume levels. Extreme high frequencies lose finesse and natural decay.

Costly (three times metalized film) film and foil capacitors selected by ear feature: low Equivalent Series Resistance (ESR), low electrical Q, very high voltage and current ratings for very precise amplifier control and electrical efficiency with quiet operation and high internal power dissipation. Uniform tension manufacturing techniques over the Mil-Spec internal elements ensure high repeatability and consistent electrical values under all operating conditions.

Metalized film capacitors are typically used. High volume levels listened to at length become fatiguing. Does not pass all the low-level signal information and tends to sound "noisy". Highs lose detail and midrange harmonic structure is modified, sounding unnatural. A disadvantage in "transparency" and apparent speed.

Resistor selection is highly critical and here the Sason Ltd uses a Mil-Spec very low inductance wire-wound unit with a very low (50 PPM) temperature coefficient. An excellent power rating and thermally stable mounting arrangement further ensures clean, clear, precise operation.

Still seen in the highest regarded loudspeakers today, typical sand cast resistors are unstable due to a high temperature coefficient and high inductance.  Loss: Dynamic compression at high volume levels due to overheating and high inductance will combine to lend a "grainy" and metallic sound and unstable operation. This type of resistor is a poor audio device! Exotic metal-film types have limited frequency band width over long listening sessions and high sound levels due to heat intolerance. Heat instability varies the crossover filter's target response, thereby allowing sound coloration to set in over time.

Very large gauge (10 AWG) air core inductors with very low resistance, high-purity round cross-section copper and optimized coil cross-section geometry for audio. Skin-effect is a desirable attribute (for audio design) in the coil, allowing a highly efficient method of high frequency filtration, coupled with low DC resistance and proper coil cross section geometry. The high quality enamel coating, low tension winding to preserve the copper crystal structure and a proprietary vacuum-sealed enamel baking process ensures unbelievable bass quality and consistently smooth frequency response under highly dynamic conditions.

Flat (ribbon) conductor coils implement a high-tension construction method for proper winding. This tension pulls and stretches the conductor, compromising the crystal structure. Larger surface area between conductors require a thicker insulation to be used, increasing the dielectric interaction between conductor and insulator. The flat conductor coil, while touting a lower DC resistance, also displays a low AC resistance - a bad quality for a coil design since one is trying to eliminate high frequencies solely on the geometry of the flat conductor coil. In effect, the coil "works harder" to accomplish its goal. In addition, the desirable benefit of skin effect in a heavy-gauge round conductor coil is ignored, so the useful phase-shift component (and desirable reduction of highs) is eliminated.

Simple crossover transfer function. Third order (18 dB/oct) acoustical filter symmetrical between Tweeter and MidWoofer. Two very heavy gauge air core coils in series with the MidWoofer and one very high quality film and foil capacitor and high quality resistor in series with the Tweeter. Very low overall component count conserves the precious amplifier source energy, efficiently preserving the electrical signal and not transforming it into heat energy through dissipation by unnecessary electrical components. Summation frequency at a very low 1,700 Hz to provide extremely wide and uniform dispersion characteristics from bass throughout the crossover region and above and for the most efficient use of the chosen drivers. Our research has proven this filter design is a perfect cooperation between MidWoofer and Tweeter functions while eliminating unnecessary phase-shifting electrical components for ideal phase characteristics.

First order (6 dB/oct) transfer functions require rare and colored-sounding custom drivers or the introduction of many additional electrical components in order to perform as expected. Typical second order (12 dB/oct) transfer functions require the inverting of (absolute polarity) one drive unit in order to perform properly within the limited-band transfer region and then are out of phase beyond the transfer region (creating a "false soundstage"). Typical third order transfer functions require additional electrical components in series with the drivers due to inadequate driver selection or ill-chosen crossover frequency. Fourth order (24 dB/oct) transfer functions require a large number of electrical components to perform properly and compromise phase characteristics. Series crossovers, once thought to be the reference standard, can sound very attractive and smooth. Unfortunately, a series crossover places additional electrical components in the signal path of every driver, an undesirable outcome when the goal is to minimize parts count and raise the level of transparency. Loss: Each function listed here introduces undesirable frequency balance and/or phase shifts. High number component count transforms the precious amplifier electrical signal into heat, forever lost.

Mechanical

FreeEnergyTM

Conventional


Ultimate rigidity, stiffness and high-mass natural granite cabinet construction. All granite components are mechanically bonded together utilizing an advanced extremely high tensile strength three-part epoxy that is stronger than the granite. In effect, the enclosure is acting as a high mass and highly rigid single piece. The difference in the Sason's granite construction over other manufacturer's is in the cabinet body proper. The enclosure itself is 1.25 inch thick natural granite and not granite over wood panels. Additionally, the granite is not simply used as a front baffle alone, or as optional panels over a sub-enclosure. Stiffness is the key ingredient in reducing vibrations and resonance build-up. Granite is a superior material for remaining unaffected by driver vibrations and internal enclosure acoustical energy, thus preserving the amplifier signal. The natural resonant frequency (common to all enclosure materials) of granite is high in frequency (above the chosen crossover frequency) and of a high-Q factor (narrow bandwidth). The materials chosen and the strength of the finished unitized-construction enclosure eliminate this high-Q resonance from being excited. Granite is an ideal "launch platform" for mechanical motion since no losses can occur by the undesirable transformation of mechanical energy into cabinet vibrations. Therefore, energy is not wasted in heat dissipation through box panel resonances and flexing. The ultimate in transparency!

Most "granite" loudspeakers are really NOT natural granite - they are pseudo-granite made of Corian® or similar solid surface material over conventional wood panels and still reveal internal resonances within the audible band. This is not comparable to the transparency offered by natural granite. Those loudspeakers utilizing natural granite do so only in select areas, such as one or two panels with the rest of the enclosure relying on conventional wood-based construction with limited results. Exotic materials such as carbon fabric and epoxy resins as well as most cast concrete enclosures have resonances within the operating range of the midwoofer or bass driver. Matrix-box (or other highly-braced) wood enclosures still cannot completely control the audible effects of the material on the overall sound. Massive aluminum panels have a unique and unnatural sonic signature that must be damped. However, damping a panel to address vibrations implies amplifier energy is being wasted by transforming resonances into heat energy by dissipation into the damping material. Loss: The original source energy is transformed into various mechanical (enclosure) vibrations thereby dissipating precious amplifier energy into heat energy. Loss of transparency and apparent speed, rhythm and timing. Dipole panel speakers suffer to a significant degree.

The Sason Ltd baffle material is our own RothBoardTM, a World's First in the loudspeaker industry! To compliment the physical properties (mass and rigidity) of the natural granite enclosure Ridge Street Audio has researched many materials for the front baffle. MDF/HDF (medium density fiberboard/high density fiberboard) was a natural choice for its inert nature and friendly manufacturability but requires many layers of adhesives and paint coatings and also is somewhat soft, exhibiting poor shear strength. It proved less than ideal at the thickness required for the rigidity and mass RSAD demanded to ideally support the MidWoofer's extreme stresses. What the Sason Ltd utilizes is a very expensive special version of a hard cast polymer, 4 inches thick and uniquely CNC-sculpted along the rear perimeter of the MidWoofer to break up any possible resonances (mechanical and acoustical) and allow the maximum strength possible to support the powerful driver. Since RothBoardTM is one piece with random molecular structure, RothBoardTM is rigid in all axes.

 Segmented hardwood panels bonded laterally may have good mechanical properties in one direction (usually side-to-side) but compromise rigidity in another direction (top-to-bottom), resulting in minor flexing of the front baffle that allow internal baffle resonances to develop. Again, the amplifier is trying to get complete control of the driver yet flexing and vibration within the baffle take away some of the energy solely reserved for fully successful driver operation. Other exotic materials suffer to the same degree as described above in the discussion of enclosure materials. While many test methods for panel vibrations and resonances, such as an accelerometer fastened to the enclosure to measure vibration decay, provide general information about enclosure and materials behavior, nothing can compare to the ear's sensitivity to the chaotic behavior of a loudspeaker enclosure while playing dynamic recordings at high volume levels.

Tweeter construction: High peak-to-peak excursion (1.0 mm) with a suspension and motor assembly built similar to a woofer, with excellent linearity at extreme displacement. The hand coated and very well damped silk dome maintains a uniform shape while being driven hard. The long voice coil and extended pole piece assembly allow the very light dome to travel to its maximum limits while remaining under tight amplifier control. The magnetic fluid is lighter than conventional domes and does not slow down the voice coil's reaction time. (No "hydraulic braking".) The thick (4.0 mm) faceplate of aluminum is very rigid, resisting vibration. The massive construction of the motor assembly withstands extreme dynamic stress under use.

Flagship or statement-level dome tweeters in other systems sacrifice in these areas: Dome diaphragm mass is higher, excursion limits are more restricted, nonlinearity of the suspension occurs at extreme limits, diaphragm shape is not uniformly maintained when driven hard, thicker magnetic fluids are utilized in order to damp resonances, and critical areas of the physical structure are weak or under-supported. Loss: Artificially smooth sound, "slow" sound, noisy extreme treble region, distortion and coloration when pushed to extreme limits, and loss of inner detail and delicate harmonic structure. Loss of transparency.

MidWoofer construction: Extremely long voice coil displacement limits (over 3/4" P-P) and one of the highest BL products (a factor in motor strength) for its size, in combination with a very light Kevlar® cone in a very tight magnetic gap and extremely linear suspension system all work together to produce superbly clean, low distortion cone operation under very high volume levels. The soft rubber surround and very low-effort spider contribute to highly detailed sound at very low volume levels without the need to "goose" the volume control in order to hear naturally dynamic sound. The Scan-Speak Kevlar® cone addresses typical high frequency break-up resonance modes with an optimum combination of cone dampening compounds, the cross-weave of the Kevlar® cone material that lowers distortion due to equal in-phase and anti-phase flexing characteristics, a highly irregular-surfaced concave dust cap to damp unwanted high frequency resonances, proper choice of suspension materials and surround shape, and proper choice of assembly adhesives. The modified magnesium chassis is an excellent example of proper frame support and rigid structure design.

Traditional high end offerings include metal cone units, carbon fiber, paper, plastic (polypropylene-based), fiberglass, ceramic, foamed urethane, Nomex®, and various combinations of the above usually in the form of a composite or sandwich construction. All have unique sonic signatures and can be made to perform well. Each also have been found to exhibit the following concerns not present with the RSAD MidWoofer: Break-up resonance modes, frame flexing, limited excursion capability, non-linear operation, unnatural sound character, high cone assembly mass, weak motor system, and low sensitivity. The Ridge Street Audio modified Kevlar® MidWoofer has addressed these issues and is unique among stiff Kevlar® cones in its lack of break-up resonances, which is not proven by other Kevlar® midwoofers. Applying electrical circuits to "eliminate" cone resonances only introduces new problems and further reduces the original signal strength through additional losses.

Acoustical

FreeEnergyTM

Conventional


Reducing baffle area and eliminating small protrusions and abrupt corners, especially around the high frequency unit, accomplish the best disappearing act in a loudspeaker. Considerable attention to screws and driver frame edges as well as grill mounting hardware on the front baffle is very important. The ear picks up these sources of diffraction and the brain interprets this as emanating from a loudspeaker and not from something resembling real performers in space. From the earliest serious studies in enclosure shape and its overall influence on sound quality by Bell Labs in the 1930's to today's extensive computer modeling, it is well understood by Ridge Street Audio the many desirable features of a properly designed front baffle. The Sason Ltd granite loudspeaker features the incomparable 4-inch thick RothBoardTM's unique baffle profiling and narrow width (9.6 inches) to accomplish the best disappearing act and highest transparency.

Large baffles such as found on big speakers do not allow the sound waves to quickly "wrap around" the frontal area and also reflect a significant portion of the sound out into the listening space, even if the baffle shape and edges are properly profiled to minimize diffraction. Again, the ear interprets this as merely a copy of the musical event and not a real entity performing in space. Squared-off corners and long vertical edges are detrimental to the smooth flow of sound waves away from the enclosure and disturb all off-axis energy spread into the listening environment, which arrives at the ear as a confused and discordant sound. The brain's catalogue of "live" sounds does not contain a suitable match to the results heard as being true-to-life. All the above issues are further amplified when attempting to listen at "nearfield" distances. Transparency is severely compromised and sound field focus is diffuse.

The Sason Ltd incorporates a tilt-back angel of 8 degrees in order to align the Tweeter and MidWoofer distances to the ear. The sound waves of both drivers are arriving at the ear at appropriate times when taking into account crossover phase rotation. RSAD has found that this alignment will eliminate the fatiguing treble-forward sound heard from a strictly vertical baffle stance and contribute to a very open and spacious sound. Furthermore, adjustments to the listener's ear height will not bring about dramatic shifts in tonality and harmonic balance.

Only the best designs will account for crossover phase rotation and driver lateral displacement to acoustically align all drivers in reference to the ear. Most high end systems still mount the tweeter forward of the midwoofer or midrange driver and this affects overall tonal balance and integration, no matter the quality of the drive units and the crossover transfer function used. Again, the ear's sensitivity to these issues will cause listener fatigue over long listening sessions due to the minor "tweeter flavor" overlaying the music. The loss is a lack of sound wave integration and natural sound development and decay times.

Wide dispersion characteristics across the entire bandwidth of the Sason Ltd would be meaningless if the frequency response was uneven off-axis. Here, attention is paid to maintain a balanced and consistent off-axis response to both sides of the enclosure, ensuring full and focused stereo imaging and a wide "sweet spot". The close driver spacing and narrow cabinet width contribute to a point-source sound field to each side of the enclosure and allows one to hear precisely when proper focus is achieved during final set up. As well, the RSAD Tweeter exhibits wide dispersion characteristics into the upper treble region for beautifully rendered spaciousness and delicate detail. Wide dispersion is achieved in most well-designed high end loudspeakers but often at the expense of an uneven frequency response at the sides. The room sees a different sonic signature left vs. right of the enclosure. The reasons for an imbalance left-to-right may be caused by driver layout such as side-by-side drivers, as in a multi-way flat dipole unit using separate diaphragms for treble/mid/bass or a dome/ribbon tweeter is displaced off-center of the front baffle. Whether this is necessary to compensate for a wide baffle in order to stagger the tweeter-to-edge distances to avoid diffraction, or is simply forced by the driver technology, it is inevitable the results are a compromise that dismantle the illusion of live sound.

Ridge Street Audio Designs

Copyright 2005
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