Dynaudio will be showcasing its 40th anniversary loudspeaker, the Special Forty, at this year’s Indulgence show in London. You’ll get to see and hear it, as well as discover some of the stories behind its creation.

The Special Forty is classic Dynaudio, a simple pair of passive hi-fi speakers. But it isn’t about looking back, misty-eyed, at past glories and leaving it at that. It’s about using those glories as a platform from which Dynaudio is “launching its next set of breakthroughs”.

As a nod back to classics including the Special One, the Special Twenty-Five, the Crafft and the Contour 1.3SE, the company kept the Special Forty pure. It uses one of Dynaudio’s classic first-order crossover designs, incorporating Phase Alignment and Impedance Alignment technologies. The crossover marshals the input signal between the woofer and the tweeter – so each driver gets only the frequencies it’s supposed to, and can perform at its best.

The Special Forty uses Dynaudio’s proprietary MSP (Magnesium Silicate Polymer) material for its main driver. MSP delivers the right combination of rigidity, damping and stability for faithful sound reproduction. And, unlike many other cone materials, it doesn’t change over time.

The cone itself uses a symmetrical excursion for midrange performance. Behind it sits an asymmetrical spider – a passive harmonic rectifier. Like all Dynaudio’s other MSP cones, it’s a one-piece design (you can tell by the special balance ribs around the central dust-cap). This gives it a solid connection to the voice-coil, as well as stabilising its form. It all sits in the special AirFlow Basket – the bit that holds the whole driver motor securely in place in the cabinet.

Special Forty also features the new Esotar Forty tweeter and a new pressure conduit, which is a shaped vent in the back of the hybrid magnet system that allows more space in the rear chamber. That space allows more damping material and reduces back-pressure, while the shape itself optimises airflow coming backwards from the rear of the dome. For the woofer, Dynaudio has placed the magnet inside the voice-coil and it’s a hybrid of a powerful neodymium rare-earth magnet with a ferrite magnet

Special Forty is finished in Red or Grey Birch. Have a look (and a listen) in the Epernay room on the Champagne Terrace.