Finally, after years of painstaking development, we are proud to introduce a pair of HF drivers worthy of partnering ATC's range of formidable bass/mid and mid-range drive units. The outstanding SH25-76 and range-topping SH25-76S are the product of over 40 years' experience building the world's finest acoustic transducers.

Dual Suspension tweeter

ATC's approach to tweeter design is unique in the marketplace. By incorporating a secondary suspension component the moving assembly is naturally constrained to travel only in the axial direction. The result is a design that suppresses rocking modes and ensures lower distortion levels. The additional stability that this approach provides over more conventional tweeter construction negates the need for ferro-fluid (usually required for cooling, damping, etc). As a consequence, the magnetic gap can be made smaller allowing ATC tweeters to not only perform optimally, for longer, but also offer improved power handling over conventional designs.

While this unique tweeter topology offers superior performance, the resultant increased moving mass and overall complexity must be offset and overcome by the perfect alignment of all components. Consequently manufacturing and assembly demands exceptional care and accuracy - a level of capability that ATC excels at.

The standard SH25-76 and its ultimate 'S' spec stablemate approach these engineering challenges in different but equally successful ways. The standard tweeter has a novel and lighter moving mass bracing component, while the 'S' spec driver has an exceptionally powerful motor assembly that, when combined with the optimally stiff and lightweight coil former, delivers vanishing low levels of odd harmonic distortion and a well controlled extended frequency response beyond the limit of human hearing.

The additional stability over other designs negates the use of ferro-fluid, so ATC tweeters perform at their best for longer, and the magnetic gap can be made smaller, further improving power handling.

Fully Optimised Neodymium Motor Assemblies

Each tweeter motor assembly employs a magnetically annealed top plate and huge N48M Neodymium ring magnet, the geometry of which has been individually optimised using finite element analysis to ensure the best possible performance. Achieving an incredibly high flux density of over 2.0T in the magnetic gap, the magnet assembly of the SH25-76S is fully saturated and therefore free from the effects of flux modulation in the surrounding metalwork, lowering odd harmonic distortion to below -70dB across the operating band. The high levels of flux density in the gap combined with a short coil long gap configuration result in a linear and extended frequency response beyond 20kHz.

Acoustic Innovation

ATC is a British company that, since its formation in 1974, has been totally preoccupied with achieving, maintaining and delivering ultimate quality. Since its inception, ATC has kept steadfastly to its founders' aims of building loudspeakers and audio electronics that employ the most effective modern engineering principles.

While other audio manufactures try to keep up with - or even ahead of - their competitors, ATC is distinctly different: it continually strives to design and build loudspeakers and electronics that perform as close to perfection as it is possible to do so.

All ATC products are built to meet the challenge of the latest digital recording technologies, while providing nothing less than the best sound reproduction money can buy.

Billy Woodman

Billy Woodman
Loudspeaker Technology Ltd, Gypsy Lane, Aston Down, Stroud, Gloucestershire, GL6 8HR.
Tel: +44 (0)1285 760561 Fax: +44 (0)1285760683 Email: info@atc.gb.net

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