Полочная акустика — ATC SCM150ASL Pro

The SCM150ASL Pro is an active three-way monitor in ATC's professional line, intended mainly as a farfield or main system for larger control rooms. It takes the SCM100ASL Pro as its starting point, replaces the 12-inch woofer with a 375 mm Super Linear bass driver and enlarges the enclosure to 150 litres, which extends the low-frequency limit. As with other ATC products, it is designed and assembled by the British company at its Gloucestershire works, including the drive units and the amplifier electronics.

Key specs that matter

ATC combines a 25 mm S-Spec tweeter with dual suspension, a 75 mm Super Dome midrange and the 15-inch SL bass unit. Power comes from an onboard tri-amplifier pack of 350 W, with 200 W for the woofer, 100 W for the dome midrange and 50 W for the tweeter. The response is linear within plus or minus 2 dB from 60 Hz to 17 kHz, and the -6 dB limits measured free-standing are 25 Hz and 25 kHz. Maximum continuous SPL at 1 metre is 117 dB, 2 dB more than the SCM100ASL Pro. Coherent dispersion spans 80 degrees either side horizontally and 10 degrees either side vertically. Each cabinet measures 884 x 498 x 568 mm (HxWxD) and weighs 75 kg.

Engineering and use context

Active filtering at 380 Hz and 3.5 kHz splits the signal ahead of the three power stages, with fourth-order critically damped slopes and phase compensation, and the frequency, gain and phase correction of each amplifier is trimmed by ATC before shipping. The amplifiers use a grounded source output design. Excess drive triggers momentary gain reduction on all three channels, while the treble channel also has an r.m.s. power limiter. On the rear panel an LF contour trim offers 0 to +6 dB at 40 Hz, and a second one cuts input sensitivity by up to 6 dB, from 1 V to 2 V, although ATC notes that turning either control without the means to recalibrate can put the two speakers out of step. A clip light shows when the limit is reached. Matched pairs sit within 0.5 dB of each other. If the monitors go into a cabinet or wall recess, ATC asks for side and top clearance for cooling or for the amplifier packs to be removed and mounted remotely. Power can be 100, 115 or 220 to 230 V at 50 or 60 Hz, and the warranty is 6 years.

Pairing

The rear female XLR input is balanced with more than 10 kohm impedance, so the SCM150ASL Pro connects straight to a console, monitor controller or balanced line preamplifier. Two cables per speaker are needed, one for mains and one for the signal.

Alternatives

The ATC SCM200ASL Pro is the larger main monitor in the range, using twin 12-inch SL woofers and an outboard P4 amplifier rated at 850 W per speaker.