Floorstanding loudspeakers — Zeiler Audio SP-02

The SP-02 is a high-efficiency two-way loudspeaker from Zeiler Audio of Kilchberg near Zurich, Switzerland, a company founded by Ralf Zeiler that makes high-end audio equipment in Switzerland. It is a smaller version of the SP-01 and uses the same coaxial driver in a much smaller enclosure. Ralf Zeiler describes the aim as bringing the qualities of the SP-01 to listeners with limited space, and the maker notes that its high efficiency lets it work in smaller rooms with only a handful of watts. Swiss prices including 8.1 % VAT are CHF 19,460 in matte satin and CHF 23,350 in piano high gloss.

Key specs that matter

The SP-02 is built around a professional 15 inch coaxial driver whose neodymium motor drives a cone of glass fibre reinforced paper. High frequencies come from a compression driver rated at 113 dB at 1 W and 1 m, while the complete system reaches 97 dB at 1 W and 1 m. Impedance is 8 ohm minimum, the frequency range runs from 40 Hz to 20 kHz, and power handling is 500 W. Each cabinet measures 50 cm wide, 34 cm deep and 89 cm high including feet, and weighs 24 kg.

Engineering and use context

In a coaxial driver the horn section sits at the centre of the woofer cone, so both sections radiate from one point, which is why Zeiler calls the SP-02 a single point source speaker. The compression driver loads an elliptical waveguide with constant directivity of 80 by 60 degrees up to the highest frequencies, so the listener does not need to sit in one exact spot. The crossover is a low-loss two-way network with custom-made paper-in-oil capacitors, and all internal wiring is cryogenically treated. The woofer works in a vented enclosure whose bass port fires downward. Cabinet proportions follow the Golden Ratio to control resonances, and the walls are a sandwich of several layers of wood and non-wood materials of different density and hardness. Finishes are piano high gloss or a matte satin, and the buyer can choose any colour from the NCS system.

Pairing

As efficiency is high and impedance never falls below its rated minimum, low-powered single-ended valve amplifiers are workable partners, and so are solid-state designs, and the stated power handling leaves room for larger amplifiers too.

Alternatives

The Zeiler Audio SP-01 is the larger floorstander with the same coaxial driver, a range down to 25 Hz and a weight of 40 kg.