Bookshelf Speakers — Sonoro ORCHESTRA SLIM

The ORCHESTRA SLIM is a compact passive two-way ported speaker from Sonoro, a company based in Neuss, Germany, which describes this speaker as German in both design and development. It is the narrower sibling of the ORCHESTRA and combines a cone woofer with an Air Motion Transformer, the pleated tweeter design that the brand uses across its passive speaker range. Sonoro offers it only in pairs.

Key specs that matter

Bass and lower mids are the job of one 5.25 inch unit whose paper cone carries a PE coating, held in a die-cast basket. Above 2,800 Hz the signal passes to the Air Motion Transformer, which uses a neodymium drive and sits inside a wave guide, with a membrane area of roughly 85 cm2. Sonoro rates the frequency range as 45 Hz to 32 kHz at the minus 6 dB points. Sensitivity is 87 dB SPL measured with 2.83 V RMS at 1 m, the load impedance is 4 ohm, and Sonoro advises amplifiers of 50 to 140 W. Each cabinet measures about 180 mm wide, 327 mm high and 250 mm deep and weighs about 7.2 kg.

Engineering and use context

High density fibreboard, stiffened by an internal matrix, forms the enclosure. Apart from the two side panels, none of its walls run parallel to each other, which Sonoro uses against standing waves in the box. The wooden housing is sanded by hand, given rounded corners and finished in a matt lacquer, with small aluminium details as trim. The listed finish is matte white with silver accents. Magnetic speaker covers are supplied, so the front can be left clean when the grilles are removed, and a single set of high quality screw terminals at the back takes the speaker cable. Because the cabinet is so narrow, it suits shelves, sideboards and dedicated stands where a wider box would not fit, while the rear reflex port means some distance from the wall behind is worth keeping. The compact footprint and modest weight also make it simple to move between rooms of around 20 m2.

Pairing

With a low load and only middling efficiency, this speaker wants amplification rated for such loads, and the top of Sonoro's suggested power span allows a stronger stereo integrated amplifier or streaming amplifier. The screw terminals accept a single run of cable, so the cable cannot be split for bi-wiring.

Alternatives

Sonoro also lists the ORCHESTRA Slim (Gen.2), which keeps the same width but moves to a Kevlar-reinforced paper and bamboo woofer cone and a slightly lower sensitivity.