Drive Units, Bass Drivers | Evolution Technologies EVO-50, EVO40

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Evolution²

THE DRIVE UNITS

THE BASS DRIVERS

The bass driver(s) incorporates a new design of cone utilising our own Kevlar bi-weave process. Kevlar has immense longitudinal strength and is used in many structures where high strength and light weight are key attributes. Kevlar can be found liberally used in Formula 1 racing cars, aeroplanes, boats, spacecraft, skis and even golf clubs.

These fibre bundles are woven and impregnated with special bonding resins that are subsequently pressure formed and heat cured. The resulting material is stiff, rigid and exhibits very low levels of internal resonance. Consequently, energy losses in the cone transfer mechanism are very low.

Similarly, lateral voice coil strength is very high. We use a combination of half hard aluminium and resin bonded glass fibre. This, in turn, contributes towards some of the lowest distortion figures ever seen in conventional drivers. The dust cap/cover is of the same material as the cone.

The bass drivers operate only over the low frequency range. They are only used over their true pistonic range. The cone is terminated with a conventional large half roll of synthetic butyl rubber with excellent inherent damping qualities.

A high performance traditional ferrite magnet system is used. Motional noise can be a problem with high output bass systems. We address this by moving air through vents in the voice coil. The magnet system is also fully vented throughout.

THE BASS MIDRANGE DRIVERS (Evo² 30,40,50)

In any system featuring a cone bass/mid driver, performance and dispersion in the upper midrange band is critical, and even more so when (as in our Evo² 30 and 40 models) the midrange driver is crossing over to a dome tweeter,even one with as wide and well maintained a response as our Evo² dome tweeters.

By using a very low mass ultra stiff Kevlar cone in our bass/midrange drivers we pro- vide virtually loss-less energy transfer from the coil ensuring good impulse and dynam- ic response times. This, combined with a carefully developed cone profile and a pre- cisely shaped central coil cap projection, allows the higher bass and midrange fre- quencies to provide not just extension but also wide dispersion at the bass unit's upper crossover point. The result is a seamless crossover transition to the tweeter without the compromised off-axis performance usually associated with most 2 way designs.

Evolution²

THE 5Omm SOFT DOME MIDRANGE (Evo²-50)

Derived from our flagship ‘Airedale Heritage’ loudspeaker, we have designed a series of dome mid-range units which are exclusively used in our high-end loudspeaker products. Although costly to produce, the benefits of a using a dome mid-range – particularly one with such as wide bandwidth as our own – are lower distortion through this region, better integration throughout the frequency spectrum and an extremely wide dispersion - all contributing to a very relaxed, natural presentation.

Because each driver in a multi-way system covers a smaller bandwidth, dynamic range and transient response are hugely improved. Often this is at the cost of frequency integration but when our unique dome technology is deployed, integration between upper and lower drive units is virtually seamless.

THE 25mm 1” SOFT DOME TWEETER

The highest frequencies are handled by a soft dome driver. Our extensive research has proven these are a better choice than the metallic based domes that typically add their own character to the treble.

A feature of the tweeters, as with the mids, is wide dispersion and very low distortion, again typically less than 1% at 100dB at 1 metre. The unit features a high flux neodymium magnet structure, producing a typical efficiency of 93dB 1W@1m. This unit has a frequency response extending far beyond audible frequencies to around 45kHz.

THE CROSSOVER AND WIRING

High quality OFC cable is used in each loudspeaker for internal wiring. High quality resin fibreglass printed circuit boards are used throughout, and all connections are made to audiophile standards. All inductors used are perfect layering wound and bonded and use large gauge wire for very low insertion loss.

All capacitors used are either, low loss, low ERC polypropylene or high quality audio grade reversible electrolytics.