Полочная акустика — ATC SCM300ASL Pro

The SCM300ASL Pro is a large format three-way active main monitor from ATC, aimed at large commercial recording studios, production and post-production suites and broadcast facilities. Unlike the SCM110ASL Pro, which carries its amplifier on the cabinet, it is driven by a separate rack-mount unit, and its pair price in the UK was GBP 38,333 before VAT.

Key specs that matter

Each enclosure holds a 34 mm soft dome tweeter, the 75 mm Super Dome midrange and two 375 mm SL bass drivers. Crossovers are set at 380 Hz and 3.5 kHz. Amplitude linearity stays within 2 dB from 50 Hz to 12 kHz. At -6 dB the cut-off points are 25 Hz and 20 kHz when the speaker stands free, and 20 Hz and 20 kHz when it is soffit mounted in a wall. Horizontal dispersion is plus or minus 80 degrees and vertical dispersion plus or minus 10 degrees, both coherent. Maximum continuous level is 121 dB SPL at 1 metre. The cabinet is 884 mm high, 925 mm wide and 460 mm deep and weighs 87 kg. The 34 mm tweeter is larger than the 25 mm dome ATC uses in the SCM110ASL Pro.

Engineering and use context

Power comes from the P4, a four-way grounded source Class A/B amplifier rated at 850 W in total. Its channels deliver 275 W plus 275 W to the twin bass drivers, 200 W to the midrange and 100 W to the tweeter, so each 15-inch woofer has an amplifier channel of its own. Filtering happens at line level inside the P4 with even order critically damped networks. To guard against overload, the amplifier briefly pulls back gain through FET circuitry and also watches tweeter temperature. The SL bass drivers use additional rings of magnet material in and around the gap to limit magnetic hysteresis and the third harmonic distortion it causes, and the Super Dome midrange handles the whole band between the two crossover points. ATC designs its own transducers and assembles them by hand in England. The system carries a six-year warranty.

Pairing

Signal reaches the P4 through a balanced female XLR socket on its back panel with pin 2 hot, with input impedance above 10 kohm and a sensitivity of 2 V. That suits professional consoles, monitor controllers and balanced line preamplifiers at studio levels. Rack space for the P4 and a cable run to each cabinet must be planned. Free-standing use needs a sturdy platform able to carry the heavy cabinet.

Alternatives

The ATC SCM200ASL Pro is a further large-format three-way active monitor in the professional catalogue of the brand.