Floorstanding loudspeakers — Marten Design COLTRANE SUPREME 2

The Coltrane Supreme 2 is a loudspeaker from Marten, the Swedish manufacturer, and the prestige model of its Coltrane series. Marten voiced it using its own recording studio in Sweden as a reference, and it was shown at CES 2014, priced at around USD 480,000 per pair. It was developed around Accuton Cell drivers, the result of a joint project between Marten and Accuton, and the Coltrane series drives many of Marten's technical innovations.

Key specs that matter

The Coltrane Supreme 2 is a five-way design. The front carries a 20mm (0.75-inch) diamond supertweeter, a 51mm (2-inch) diamond tweeter, a 5-inch ceramic midrange and seven 8-inch aluminium-sandwich woofers, and the rear carries six passive sandwich radiators of about 10 to 11 inches. First-order crossovers operate at 120Hz, 450Hz, 3.5kHz and 8kHz. Frequency range is 18Hz to 100kHz (+/-2dB), sensitivity is 91dB at 2.83V/1m and impedance is 6 ohms with a 3.2-ohm minimum, with a 500W power rating. Terminals are WBT NextGen for bi-wiring, and internal wiring is Jorma Design Statement. Each speaker stands about 2m tall, measures 54 x 59cm and weighs around 230 to 270kg.

Engineering and use context

First-order crossovers roll off at only 6dB per octave, and are the only kind that can sum to the original signal with correct time and phase, but they require drivers that behave well far outside their intended range. Marten could use them because diamond and ceramic diaphragms are extremely rigid and stay pistonic across wide bandwidths. Diamond has the highest stiffness-to-weight ratio and internal sound velocity of any membrane material, and as the best known heat conductor it also acts as a heatsink for the voice coil, giving high power handling and low compression. Marten's ceramic domes are produced by an electrochemical process that raises their internal damping. In the Cell drivers developed with Accuton, tweeters, midrange and woofers share the same acoustic plane, and the midrange uses a concave profile to move its acoustic centre forward to match the tweeters, with an annular magnet that leaves the rear of the diaphragm unobstructed. The cabinet is built in three parts, with a separate midrange enclosure of Corian, stainless steel and aluminium, and carbon-fibre laminate, which Marten says greatly reduces internal reflections.

Pairing

Despite its high sensitivity, the low impedance minimum means the Coltrane Supreme 2 needs powerful, current-capable amplification; at CES it was shown with Pass Labs Xs 300 monoblocks. Its size and deep bass extension suit very large rooms.

Alternatives

Marten's own Coltrane Tenor 2 applies the same diamond and ceramic Accuton technology to a smaller Coltrane model.