Floorstanding loudspeakers — Piega COAX 611

The Coax 611 is a Swiss-made three-way tower speaker from Piega SA, the Swiss firm based in Horgen on Lake Zurich after moving from Geneva. It belongs to the Coax line, built around the company's coaxial ribbon driver, and the current Gen2 version is listed at GBP 14,900, USD 19,995 or EUR 15,900 per pair.

Key specs that matter

Piega quotes 32 Hz to 50 kHz, a sensitivity of 90 dB at 1 W and 1 m and a nominal load of 4 ohm, and suggests amplifiers between 20 and 250 W. The ribbon unit covers the band from 450 Hz up to 50 kHz. Below it sit two 160 mm UHQD woofers, which SEAS makes to Piega specification, and three 160 mm UHQD passive radiators replace a bass port. These cones use aluminium membranes with titanium voice coil formers. Each speaker measures 117 cm high, 21 cm wide and 31 cm deep and weighs 45 kg.

Engineering and use context

The C112+ coaxial ribbon places the tweeter diaphragm in the centre of the midrange ribbon, so both radiate from one axis. Piega describes this symmetrical layout as a point source that keeps the two drivers aligned in time and improves impulse behaviour. In the Gen2 driver the bar magnets that steer the diaphragms are mechanically decoupled from the chassis, which cuts vibration at certain frequencies, more neodymium magnets sit above the tweeter, and the ribbon foil has a newly developed coating. The curved enclosure is extruded aluminium, with seams only at the top and bottom plates. Inside sits a Tension Improve Module 2, a set of stout aluminium braces between the drivers that puts the walls under tension to control resonance, and Gen2 adds further cross-bracing. Bi-wire terminals are linked with short pieces of copper wire in place of flat metal jumpers. Finishes include brushed aluminium in silver or black anodised, white lacquer, and eight special colours such as Blue Lagoon, Misty Green, Desert Gold and Bordeaux Red.

Pairing

With the low nominal impedance, amplifiers that deliver steady current into low impedances are the safest match, and the low end of the recommended power range shows that modest power is still usable at normal levels. The split terminals allow bi-wiring or two amplifier channels per speaker for bi-amping. Piega also offers an optional wider plinth base that adds stability on hard floors.

Alternatives

The Piega Coax 711 is the bigger floorstander of the line, using two 220 mm woofers and two 220 mm passive radiators in a 118 x 28 x 33 cm cabinet weighing 47 kg.