The Special Forty is a two-way, reflex-loaded, standmount monitor that leverages design elements drawn from more costly Dynaudio models, starting with an inherently phase coherent first-order crossover network said to incorporate the firm’s unique phase and impedance alignment technologies. The speaker uses a 17cm MSP (Magnesium Silicate Polymer) mid-bass driver that is unique to the Special Forty but is visually and sonically similar to mid-bass drivers found in the firm’s more costly Confidence and Evidence speaker ranges. Distinctive design touches in the Special Forty woofer include a special Nomex spider that is claimed to enable “even more symmetry in the driver’s excursion”, thus enhancing midrange clarity and definition. Moreover, the driver uses an advanced version of Dynaudio’s proprietary AirFlow Basket system that is extremely rigid and stable yet presents a bare minimum of reflective surfaces behind the driver diaphragm.
The motor of the woofer is special too, with a driver magnet positioned within—and not surrounding—the driver voice-coil, which better focuses the magnetic flux field on the voice-coil while reducing the amount of material behind the diaphragm, thus reducing internal reflections. Finally, the magnet used in the Special Forty woofer is a hybrid design that applies both Neodymium and Ferrite magnet materials for a nearly ideal combination of power and control, further enhancing symmetrical driver excursion while reducing second-harmonics.
Handling upper midrange and high frequencies, the Special Forty uses a 28mm Esotar Forty tweeter similar to the Esotar-series tweeters found in most of Dynaudio’s upscale models. The tweeter diaphragm is treated to what the firm whimsically calls a DSR (Dynaudio Special Recipe) coating. Much like the Special Forty woofer, the Esotar Forty tweeter goes to great lengths to optimise airflow from the rear side of the driver diaphragm. Accordingly, the driver features a distinctive ‘pressure conduit’, described as “a shaped vent in the back of the magnet system that allows more space in the rear chamber,” thus allowing the manufacturer to pack in more damping material while reducing back pressure on the diaphragm. In turn, the driver also uses an ‘aero-coupled pressure release system’ positioned beneath the tweeter voice-coil and that prevents unwanted pressure build up while reducing resonance and increasing the tweeter’s ability to render fine, low-level high-frequency details.