TACTIC II DRIVE UNIT

There are no transient delays in nature – when a singer sings, or a drummer strikes you hear the sound almost instantly. But when a drive unit tries to replicate this sound from a recording, the transient response time, although minute, is easily detected by the ear and the brain. When designing a drive unit, it is critical to reduce the transient response time as much as possible. Any delay, informs the brain that what is being listened to is in fact a recording and not a real human voice or instrument.

Wilson Benesch developed the original Tactic drive unit and subsequent Tactic II drive unit around this philosophy. We employed a light cone material, with phenomenally powerful NdFeB Rare Earth Magnets, with a highly evolved motor geometry to optimise flux. The result was a dynamic drive unit that could excurse through the in and out range of its movement during use very quickly and under a high degree of control. The original Tactic design was described as “lightning fast” in the first test reviews.

ISOBARIC DRIVE SYSTEM

In the Isobaric Drive design, Wilson Benesch extend the philosophy of the Tactic a step further. By deploying two Tactic II drive unit, conventionally connected, with the motor coils wired in parallel, the composite dual driver has the following characteristics if compared with a single device: twice the moving mass, half the compliance, half the impedance for which it draws twice the input current and hence double the power.

In layman’s terms, the Isobaric Drive works harmoniously in a push-pull formation, dividing the load of creating low frequency sound across two powerful drive units. By sharing the load of the work, the Isobaric Drive can produce extremely low bass, while remaining highly dynamic and perfectly integrated with the midrange drive units.

In the Resolution, Wilson Benesch have deployed a total of 4 Tactic II drive units across two independent Isobaric Drive systems in a clamshell formation.

SEMISPHERE TWEETER

Designed and manufactured in house, the Semisphere has been developed to match the Tactic II Drive Unit, creating seamless integration across the mid-high frequency band. At the heart of the Semisphere is the Silk-Carbon Hybrid Dome. The hybrid dome tweeter, retains the natural sound of a soft dome tweeter, remaining free from sibilance. However the addition of carbon fibre through a proprietary technique, allows the Semisphere to remain flat through the frequency range to 30kHz.

Built around the dome is a combination of highly engineered components, which have been precision machined in house at Wilson Benesch. At the front a curved front plate creates the ideal launch surface for high frequency sound. To the rear of this is a complex motor front and rear plate that hold a ring of six powerful rare earth magnets. The design allows optimal venting and allows the Semisphere to remain cool during extended use.

TROIKA SYSTEM

The midrange frequency band is where the human ear is most sensitive and thus was a key area of R&D during the development of the Cardinal. The resulting Troika System is a unique drive unit topology that is central to the success of the Resolution loudspeakers lucid and highly transparent soundstage.

The topology sees the Semisphere Tweeter flanked by a lower midrange / bass Tactic II driver above and an upper midrange Tactic II driver below. The Troika System technology has been used in other Geometry Series designs.

Not only does the Resolution have dedicated upper and lower midrange drive units, but these drive units are also acoustically tuned by a combination of cabinet air volume and individually specified drive unit design. Thus in the Cardinal, both midrange drive units are coupled directly to the amplifier with no crossover components in the signal pathway, while there is a Semisphere has just a single inductor on it. The midrange is therefore free of any phase anomalies or signal degeneration associated with complex crossover designs.

CABINET CONSTRUCTION

The enclosure exerts a considerable influence over the sound of the complete system. A moving coil driver radiates energy by vibrating a diaphragm assembly whose reaction will simultaneously excite the loudspeaker chassis causing it to vibrate in sympathy. The chassis must therefore be ridged and highly damped to prevent it from moving and in turn stop the chassis from dissipating energy as unwanted acoustic output.

Numerous examples of chassis damping are evident in the Resolution. The A.C.T. Monocoque alone is the most highly damped loudspeaker enclosure ever manufactured. However, Wilson Benesch also employ steel bars to internally brace the cabinets in each Geometry Series loudspeaker. In the Resolution three 14mm steel bars brace the chassis between the foot and the mid-plate, clamping the entire enclosure around the powerful Isobaric Drive. Much like a cathedral roof, the bars or struts tie panels to one another, bracing and stiffening the panel and in turn damping the cabinet.

A.C.T. MONOCOQUE

A sophisticated three-layer composite structure comprised of carbon fibre, high compression blast core and glass fibre. In terms of energy damping and therefore signal-to-noise ratio, the A.C.T. Monocoque exceeds with consummate ease the materials traditionally used in loudspeaker design.

Wilson Benesch have optimised the A.C.T. Monocoque by creating a curved form. The geometric form of the cabinet negates standing waves by reducing the number of flat surfaces on the loudspeaker surface. Thus any sound waves interacting with the surface of the A.C.T. Monocoque are diffracted across a wide angle and thus diminished. As a result such distortions are impossible for the ear to detect, allowing the loudspeaker to disappear within the listening space; stealth like the loudspeaker creates a wide open and life like soundstage.

TROIKA BAFFLE

Resolution features a unique aluminium profiled baffle to house the three drive units that comprise its Troika System. The baffle is machined from two solid billets of aluminium, to create a beautiful curved, stepped baffle feature at the front of the Resolution.

As standard throughout the Wilson Benesch reference loudspeaker line, Geometry Series, the Resolution baffle is constructed entirely from aluminium that has been precision CNC machined in house. But, alike with the Isobaric Drive System sub-baffle in the Cardinal, the 4kg Troika Baffle in the Resolution is a highly engineered multi-profiled component that plays a crucial role in the function of the loudspeaker.   In the Resolution, the Troika Baffle is perhaps a feature that most strongly defines the loudspeaker visually from its stable mates.

CARBON FIBRE TOP

Following the same principles of the A.C.T. Monocoque, the carbon fibre top in the Resolution, Cardinal, A.C.T. One Evolution and the Endeavour has been designed firstly to damp internal cabinet born resonance and secondly to negate standing waves interacting with the loudspeaker surface. The overall effect is vastly improved signal-to-noise ratio.

The Resolution carbon fibre top, like that of the Cardinal and Endeavour, are perhaps the most complex carbon fibre forms ever created by Wilson Benesch. Starting life as a hand-formed clay sculpture, evolving in turn to a wax model, which has then been scanned by a laser at the Advanced Manufacturing Research Centre in Sheffield to create a 3D computer model. This process allows a highly complex organic structure to be created, the like of which would be almost impossible to create digitally. The result is a beautifully sculptural form, with no compromise in terms of its function.

KINEMATIC LOCATION

First introduced in the kinematic bearing design in the Wilson Benesch A.C.T. One Tonearm in 1991, the bearing was designed on the principles of kinematic coupling. The fundamental principle of kinematic coupling is to selectively eliminate each one or all of the six degrees of mechanical freedom that any physical body has.

In the Resolution, three 28mm steel threads, each tipped with a 12.5mm steel ball, meet with three 12.5mm steel balls, held captive inside the floor protector. This creates a triangulated structure, with a contact point of less than 1mm2. This provides high-integrity, stable location of the loudspeaker.