ATC Loudspeaker Technology’s new SCM19 Active Tower speaker system was conceived to deliver the company’s reference-quality audio from an elegantly curved floor-standing design, just 370mm wide and under a metre in height. Identical acoustically to ATC’s passive SCM19 2-way but utilising the 19 litre volume in a slim tower format the SCM19AT’s braced, sealed and curved multi-layer laminated cabinet provides a rigid and optimally damped environment for the company’s SH25-76 soft dome tweeter and 150mm Super-Linear mid/bass driver. Drive units are individually powered by an upgraded bi-amp pack (also proprietary), comprising ATC’s discrete MOSFET Class A/B modules, providing 32W of continuous power to the tweeter and 150W to the woofer.
SH25-76 tweeter
Sharing technology with the renowned ATC soft domed mid-range drive unit, the 19AT’s tweeter employs a unique dual suspension system, designed to suppress rocking modes even at high power output levels. The ATC configuration of a short edge-wound voice coil in a long, narrow magnetic gap ensures exceptionally low distortion throughout the tweeter’s operating band and removes the need for ferrofluids, which can dry out over time, compromising performance. A complex-shaped, soft-domed diaphragm extends high frequency range and offers a smooth off-axis response. The tweeter’s 15,000 gauss (1.5 tesla) neodymium magnet has a black heat-treated top plate, which dissipates heat away from the voice coil to maintain high power handling and low power compression. A precision-machined 5.5mm rigid alloy waveguide provides optimum dispersion.
Bass driver
The SCM19AT’s 150mm ATC SL mid/bass driver utilises a carefully weighted doped fabric cone with a 75mm soft dome – exceptional for its broad and even dispersion of mid-band frequencies. The cone is driven by an ‘under-hung’ (short coil/long gap) motor using a huge 9kg ‘Super Linear’ magnet system, which is unique to ATC loudspeaker systems. The 75mm ribbon wire voice coil is meticulously milled and wound in-house by ATC.
Electronics
The 19AT’s proprietary two-way on-board amp pack design has been revised to reduce noise and distortion (a further -10dB @ 10kHz), while achieving a lower operating temperature for improved reliability. The design includes protection circuits for both DC offset and thermal overload. Mid frequency THD is vanishingly low at 93dB/0.002%, and a very wide bandwidth of 200 kHz ensures the accurate reproduction of musical transients. ATC’s Grounded Source output stage modules are fed by a newly developed two-way active crossover section featuring 2nd order modified Butterworth circuitry with phase compensation for each crossover point.
The ATC SCM19AT – the first active 19 in the company’s history – is designed for optimum performance with the grille attached, although the difference in performance without the grill is minimal. Finished in anthracite grey, the metal grille fixes to the cabinet via hidden magnets. Designed and manufactured by ATC entirely in-house, the SCM19AT offers the ownership of a hand-built ruggedly engineered speaker system, world famous for musical accuracy and high power output. Like all ATC products, the SCM19AT is backed by a six-year warranty. The SCM19ATs retail for £4,990 per pair and are available now.