Seamless distribution of a full spectrum power band across a number of drivers has always been a challenge for dynamic loudspeakers using different drivers (woofer, midrange tweeter etc). The various drivers are usually made of different materials with different resonances, damping properties, efficiencies and linearities. The passive cross-over components introduce further non-linearities, distortions, and depending on the complexity, phase shifts which significantly impact imaging in stereo systems, and impulse response. Full range electrostatic speakers side step these issues but have to be quite large for adequate power output. Because the ear is most sensitive to mid range frequencies, many UK loudspeaker companies pay particular attention striving for the best possible performance in this region above all else.
Wilson Benesch has used it's unique Isotatic Polypropylene cone material to cross-over to a tweeter at 5Khz from their standard 7" tactic driver (in upper bass/midrange configuration) while adding an additonal tactic bass driver for a 2.5 way design. Simple low order cross-overs have been used with the amplifier directly driving the midrange. Like the Cardinal, in the A.C.T. One Evolution the midrange is split across two drivers. The upper midrange, with the tweeter, is housed in the separate volume-optimized upper cabinet that is acoustically rolled off for a seamless integration with the lower midrange and bass in the bottom cabinet. The high powered semisphere tweeter is placed at the heart of this midrange formation for better point source imaging.
Slight differences in the isotactic cone composition are possible in this arrangement for frequency range optimization while still belonging to the same family. The mid-range power band is increased, and similarly the hand over to the bass driver is even smoother. What is clever about this arrangement is that both mid-range drivers are still directly driven by the amplifier since acoustical means (the cabinet itself) rather than electical means are used to roll over the drivers. The critical midrange is thus free from the phase shifts and non-linearities of complex cross-overs.
The advanced Wilson Benesch Semisphere tweeter is used in all the geometry speakers. The powerful magnets and massive heat absorbing rear end cap in the optimized vented housing is huge compared to many tweeters, which behind a face plate are little bigger than a dollar coin. Together with a low mass diaphragm, linear power response extends smoothly to beyond 35 KHz and the tweeter only requires a minimal first order cross-over which rolls the tweeter off at 5 KHz.
The top of the A.C.T. One Evolution loudspeaker is decended from the sloping top design of the original A.C.T. One loudspeakers launched in 1985 and the first example in the industry of a speaker using a sloping top design. As in the Cardinal and Endeavour speakers the top is an important contribution to the soundstage and presentation.
Like the Vector, the A.C.T. One Evolution loudspeaker is built on a substantial machined aluminum block but this time hand wheels and kinetmatic bearing cups are brought down from the Cardinal and Endeavour speakers together with the recessed terminals for a clean look.
The Wilson Benesch Geometry series speakers feature solid metal machined baffles and stiff light monocoques cabinets with minimal internal bracing. These high signal-to-noise ratio low coloration cabinets when combined with directly driven midrange, optimally damped bass and high power linear tweeters have a transparancy and detail retrival that is very close indeed to electrostatic speakers. Many dynamic wooden box speakers have a slow bloated bass, veiled midrange and weak treble. The measures which are used to compensate for conventional speakers with these characteristics include, "sparkly top end, forward midrange and tight bass" cables and class D amplifiers. In such systems Wilson Benesch Geometry speakers can have too much energy in the midrange and treble which can sound over powering especially in lively rooms. With good class A or class A/B neutral amplifiers and neutral cables the speakers will be better balanced and the mid range clarity and details will then be simply stunning with especially vivid vocals. Now turn up the volume a shade and the sound will become amazingly life-like and you will better appreciate the well-defined bass and lack of cabinet sound - just the opposite to what you get with conventional speakers at high volume. You will easily be able to assess the rhythmic timing characteristics of your cables
The A.C.T. One Evolution loudspeaker covers all the bases and is a very useful addition to the Geometry series. It is a forward thinking beautiful speaker that is relatively compact, not difficult to drive, and has class leading performance.
Wilson Benesch A.C.T. One Evolution loudspeakers come standard with a British aerospace quality silk black finish, or real wood veneers applied by Bentley trained craftsmen, or architectural grade polymer color finishes and are hand-built to order with a delivery time of approximately 10-12 weeks.
Wilson Benesch is located in Sheffield England - the traditional home of steel engineering in the UK - and is the only U.K. audio company to have won substantial government funding for its innovative development work.