Floorstanding loudspeakers — Fischer & Fischer SN/SL 270 AMT

The SN/SL 270 AMT is the first model in the Fischer & Fischer range to use an Air Motion Transformer tweeter, custom made by Mundorf to the company's specification. It is the same AMT fitted to the SN 1000.1 AMT. Like all models of the German maker, its cabinet is built from natural slate, supplied in the natural SN finish or the polished and lacquered SL finish.

Key specs that matter

Two 160 mm Fischer & Fischer cone drivers with woven polypropylene membranes, die-cast aluminium baskets and phase plugs cover bass and midrange, and the Mundorf AMT handles the treble. The crossover uses first and second-order phase and impedance-corrected filters. Frequency response is 39 Hz to 27 kHz, sensitivity is 89 dB and impedance is 4 ohms. Maximum sound pressure is 112 dB. The cabinet measures 970 x 184 x 250 mm (H x W x D), or 1040 x 205 x 270 mm with its base plate, and weighs 42 kg.

Engineering and use context

In an Air Motion Transformer, a folded membrane expels air from its pleats, so a small movement of the membrane produces a larger movement of air. This allows a low moving mass for a given output and gives the AMT high efficiency and output capability, which is part of why this model plays louder than the dome-tweeter SN/SL 270. The bass reflex port fires downward as standard, with front-firing and rear-firing port versions available as options for positions where the floor coupling does not suit. The woven polypropylene cones combine stiffness with damping, and the phase plugs replace dust caps to smooth midrange output. The low-order filters with phase correction keep the transition between drivers gentle, and the slate cabinet itself is slightly lower than the overall height quoted with the base. The cabinet walls are natural slate plates of 12 to 20 mm, stiff and self-damping, sitting on a spiked 40 mm slate base plate, and the SN finish shows the split grey stone. Unlike the bi-wired SN/SL 270, connection is single-wire through 63 A rhodium-plated terminals. Since the SN 1000.1 AMT costs several times as much, the SN/SL 270 AMT is the most affordable way into the company's AMT designs.

Pairing

The SN/SL 270 AMT suits solid-state amplifiers of 60 W per channel or more in rooms of 18 to 30 m2. The downward-firing port allows placement fairly close to the rear wall.

Alternatives

Fischer & Fischer's SN/SL 470 adds a dedicated midrange driver and a second woofer to the same Mundorf AMT.