Loudspeakers

Front and centre of the tall, elegant fenestria is the PMC75-S midrange dome, a development of the iconic PMC75 used in PMC's active studio monitors and SE Home models for years. Previously, PMC had damped internal resonances immediately to the rear of the dome but has greatly improved this in the PMC75-S by using a vented (hollow) pole-piece to dissipate rear-radiated energy into a separate chamber. The latter extends out from behind the motor structure, its computer-modelled profile spun from a single piece of aluminium. A bitumastic material coats the inside of the chamber together with multiple layers of acoustic foam to absorb the unwanted rear output of this mid driver. Reduced distortion and improved response 'flatness' are the key benefits, the latter also enhanced by the re-designed, two-part 150mm magnet and motor design with its copper shorting ring.

The dome driver itself is made from cotton, impregnated with a plasticised lacquer to combine light weight with a high degree of self-damping. A dual suspension/surround, also fashioned from a doped cotton but with a tighter weave, permits greater displacement without rocking – read higher SPLs with lower distortion. The entire midrange assembly is isolated from any main cabinet vibrations by PMC's 'Nest' – a profiled, machined aluminium frontispiece mounted onto the cabinet with silicone bushes. The compliance operates over three axes and is tuned to be effective down to very low frequencies, claims PMC. PM