Floorstanding loudspeakers — Fischer & Fischer SN/SL 470

The SN/SL 470 is a three-way passive floorstander built in Schmallenberg, Germany, by Fischer & Fischer, a company whose entire loudspeaker catalogue uses cabinets cut from natural slate. It sits directly above the 2½-way SN/SL 370 AMT and is offered alongside a revised SN/SL 470 M. Buyers choose SN, the raw slate surface, or SL, where the stone gets a polish plus lacquer in any RAL colour or in available automotive paints.

Key specs that matter

The low range relies on two 180 mm Fischer & Fischer cones, each with a carbon paper foam sandwich membrane. A third 180 mm cone covers the midrange, using a carbonized paper and carbon foil sandwich with an aluminium phase plug, while a Mundorf-built Air Motion Transformer made specially for the brand takes the top octaves. Published figures are 34 Hz to 27,000 Hz at plus or minus 3 dB, 4 ohms, 89 dB for 1 W at 1 m, and 112 dB maximum output. The bare slate enclosure is 1115 x 220 x 350 mm and the overall footprint with the floor system reaches 1160 x 325 x 405 mm. The weight per speaker is 89 kg.

Engineering and use context

The cabinet is tuned as a bass reflex enclosure with slate panels of 20 and 23 mm. Filters in the crossover are 1st and 2nd order and corrected for phase and impedance. According to the maker, slate has a layered structure and extreme mass, which stop the enclosure walls from vibrating and draining energy from the drivers, and this lets the cabinets stay compact enough for a home. The company adds that older speakers can be brought up to current technology later on. An aluminium foot assembly with levelling adjustment carries the cabinet. Its current catalogue runs from compact two-way boxes to the SN/SL 1000.1 AMT four-way design, and the 470 is the first of its three-way towers. The firm describes its rock as formed over close to 500 million years, and credits the high mass reactance of slate with keeping the front baffle still behind the tweeter.

Pairing

Connection is by bi-wiring, using 63 A rhodium plated terminals and pure silver bridges that link directly to the crossover without loss. Owners can therefore feed each speaker with one cable pair or split the bass and upper sections onto separate runs. The low nominal load should be matched with an amplifier rated to drive it.

Alternatives

Fischer & Fischer also lists the SN/SL 470 M, a bi-wired three-way floorstander with the same rated frequency range and a quoted weight of 88 kg.