Bookshelf Speakers — ATC SCM110ASL Pro

The SCM110ASL Pro is a three-way powered monitor for studio use from ATC, the English company which designs and hand builds its own drive units. In practice it follows the SCM50ASL Pro recipe with two 9-inch bass units in place of one, housed in a larger enclosure, and it targets larger recording and mixing rooms as well as mastering suites.

Key specs that matter

ATC fits a 25 mm dual suspension S-Spec tweeter, the 75 mm Super Dome midrange and a pair of 234 mm SL bass units. Crossover points sit at 380 Hz and 3.5 kHz. Amplitude linearity is held within 2 dB from 50 Hz to 17 kHz, and the free-standing cut-off points at -6 dB are 30 Hz and 25 kHz. Dispersion is quoted as plus or minus 80 degrees horizontally and plus or minus 10 degrees vertically, both coherent. Maximum continuous output reaches 115 dB SPL at 1 metre. The onboard grounded source tri-amplifier totals 350 W, split into 200 W for bass, 100 W for the midrange and 50 W for the tweeter. Each cabinet measures 715 mm high, 625 mm wide and 420 mm deep, with about 76 mm more depth for the amplifier pack at the rear, and weighs 73 kg.

Engineering and use context

With a separate amplifier channel feeding each driver, the crossover operates at line level ahead of the power stage, using even order critically damped filters. The SL bass units carry extra rings of magnet material inside and outside the gap, which ATC uses to counter magnetic hysteresis in the steel and so reduce third harmonic distortion from the upper bass into the midrange. The Super Dome midrange traces back to 1976 and handles the entire midband on its own. Overload protection works through active FET momentary gain reduction, with thermal protection for the tweeter, and clip indication warns before the amplifiers run out of headroom. An LF contour control adds 0 to 6 dB at 40 Hz, continuously variable, to balance bass output against placement. ATC gives a six-year warranty.

Pairing

Signal enters through a rear panel female XLR wired pin 2 positive, with balanced input impedance above 10 kohm. Nominal sensitivity is 1 V, and a continuously variable trim from 0 to -6 dB covers sources delivering between 1 V and 2 V. A balanced output from a mixing console, monitor controller, DAC or line preamplifier is the natural feed, and no external power amplifier is involved. Given the weight, sturdy stands or a solid platform are needed.

Alternatives

The ATC SCM150ASL Pro is another three-way active monitor in the same professional line from this maker.