Floorstanding loudspeakers — Fischer & Fischer SN/SL 470 M

The SN/SL 470 M is a three-way tower in the slate-cabinet range of Germany's Fischer & Fischer. It is a step up from the two-way models in the range, adding a dedicated midrange driver to a pair of woofers and a Mundorf Air Motion Transformer tweeter, and a more elaborate crossover and cabinet. It is available in natural slate (SN) or polished and lacquered slate (SL).

Key specs that matter

Two 180 mm Fischer & Fischer cone drivers with a carbon paper and foam sandwich membrane handle bass, one 180 mm cone driver with a carbonised paper and carbon foil sandwich membrane and an aluminium phase plug covers the midrange, and a Mundorf AMT custom made to Fischer & Fischer's specification takes the top octaves. Low-order networks with phase and impedance correction divide the signal, and the box is vented. It covers 34 Hz to 27 kHz (+/-3 dB), sensitivity is 89 dB and impedance is 4 ohms, with maximum sound pressure of 112 dB. The speaker measures 1160 x 325 x 405 mm and weighs 85 kg.

Engineering and use context

Fischer & Fischer cuts this enclosure from natural slate plates 20 to 23 mm thick, thicker than in the two-way models, which increases stiffness and mass to match the larger drivers and higher output. The stone is dense and damps itself internally, so panel resonances remain low. Splitting the range into three bands lets the midrange driver work only across the vocal region, while two woofers share the bass. The sandwich construction of the cones combines low mass with internal damping, and the aluminium phase plug on the midrange replaces a dust cap. The AMT's pleated membrane squeezes air out of its folds, producing high output from a small moving mass. The low-order, phase-corrected filters keep the transitions gentle. The speaker stands on an aluminium floor system that is height adjustable for levelling. Bi-wire terminals rated at 63 A are rhodium plated, with pure silver bridges connecting directly to the crossover. The SN finish shows the stone's natural surface, while SL gives a smooth, coloured lacquer over the slate, useful when the speakers must match a room.

Pairing

The SN/SL 470 M presents a low-impedance load and works with solid-state amplifiers of 100 W per channel or more. Its deep bass extension and large cabinet suit rooms of 25 to 45 m2.

Alternatives

Fischer & Fischer's SN 770.1 AMT is the larger four-way model of the range with 92.5 dB sensitivity and tri-wiring.