Напольная акустика — ATC SCM300ASLT

The SCM300ASLT is the active version of the SCM300 tower in the ATC Tower Series. Its amplification is not built into the cabinet - each speaker is driven by an outboard P4 filter and amplifier unit, and a pair ships with two P4 units and 5 m of speaker cable. A passive SCM300PSLT with tri-wire binding posts is offered as well. The UK price starts at GBP 52,000 per pair and rises to GBP 61,500 depending on finish.

Key specs that matter

Every cabinet carries a 25 mm dual suspension S-Spec soft dome tweeter, a 75 mm Super Dome midrange and two 375 mm SL bass units, crossing over at 380 Hz and 3,500 Hz. The P4 supplies 275 W to each bass driver, 200 W to the midrange and 100 W to the tweeter, 850 W per speaker. Amplitude linearity is plus or minus 2 dB from 50 Hz to 12 kHz, with -6 dB cut-off points at 25 Hz and 20 kHz measured free-standing. Maximum continuous output is 121 dB at 1 m. The balanced XLR input has 2 V sensitivity and an impedance above 10 kohm. Coherent dispersion reaches plus or minus 80 degrees horizontally and plus or minus 10 degrees vertically. Each cabinet measures 1500 x 500 x 580 mm and weighs 96 kg, and the warranty covers 6 years.

Engineering and use context

The P4 is a four-channel, three-way Class A/B design using a grounded source output topology. It holds the three-way active filters and four power amplifiers - one for the tweeter, one for the midrange and two for the pair of bass units - in a 19-inch case that takes 5U of rack space. The electronics can be placed remotely from the monitors, with a single custom eight-way cable linking each cabinet to its P4. The filters are even order and critically damped. Protection combines active FET momentary gain reduction with a thermal circuit for the tweeter. For comparison, the passive version is rated at 93 dB per W, 8 ohm nominal and 120 dB continuous output. Standard finishes are cherry, walnut, oak and black ash veneer plus satin black and satin white paint. Rosewood, European crown cut walnut, pippy oak, burr magnolia and burr poplar veneers, clear high gloss, piano black and piano white cost extra.

Pairing

A preamplifier or DAC with variable balanced outputs connects directly to the P4 inputs, and the relatively high sensitivity figure calls for a source able to deliver a full line level. Each P4 feeds one speaker only, so a stereo system always runs two of these units.

Alternatives

The ATC SCM200ASLT uses the same P4 amplifier with a pair of smaller 314 mm SL bass drivers in its tower cabinet.