Полочная акустика — ATC SCM20PSL Pro

ATC's SCM20PSL Pro is a small unpowered two-way studio monitor, from the British loudspeaker maker based at Aston Down in Gloucestershire, whose drive units are hand-built in its own UK facility. It was introduced alongside the active SCM20ASL Pro as an entry point into ATC studio monitoring, keeping the same drivers without the built-in amplification. ATC designs it for critical near-field listening in control rooms, LCR monitoring in small and medium rooms, and surround channels in larger rooms, and it carries a six-year warranty.

Key specs that matter

The SCM20PSL Pro combines ATC's 150mm (6-inch) Super Linear bass/mid driver with a 75mm voice coil (SB75-150SL) and ATC's own 25mm dual-suspension soft-dome tweeter (SH25-76S). Amplitude linearity is 80Hz to 20kHz (+/-2dB), with -6dB cut-off points at 55Hz and 25kHz when freestanding. Dispersion is +/-80 degrees horizontally and +/-10 degrees vertically. Maximum SPL is 108dB continuous per pair at 1m. It shares its drivers with ATC's domestic SCM20PSL, rated at 85dB sensitivity, an 8-ohm nominal and 5.5-ohm minimum impedance, a 2.2kHz crossover and 75 to 300W amplification. The cabinet measures about 440 x 239 x 325mm and weighs around 17kg.

Engineering and use context

The SH25-76S is the first tweeter designed and built entirely by ATC, the result of six years of development by managing director Billy Woodman and R&D engineer Richard Newman. It borrows the dual-suspension layout of ATC's midrange dome, which centres the diaphragm without ferrofluid in the magnetic gap, avoiding the gradual change in behaviour as ferrofluid dries out over years of use. A large neodymium motor with a heat-treated top plate extends high-frequency response with low distortion, and the precision-machined alloy waveguide shapes dispersion while remaining rigid and free of resonance. The bass/mid driver uses a short-coil, long-gap motor - a short voice coil working inside a longer magnetic gap - so the coil stays in a uniform field throughout its travel, keeping the driving force linear. Its 75mm voice coil provides the power handling and low power compression usually found in much larger drivers. ATC's Super Linear technology uses special materials in the magnetic circuit to reduce third-harmonic distortion in the lower midrange. The MDF cabinet has internal bracing and elastomer damping panels, and heavily rounded front edges reduce diffraction.

Pairing

With low sensitivity typical of ATC designs and a demanding bass/mid driver, the SCM20PSL Pro needs a clean, powerful amplifier with generous current. It suits near-field placement on rigid stands in control rooms and small listening rooms.

Alternatives

ATC's own SCM20ASL Pro is the active version with built-in 200W and 50W amplifiers for the same drivers.