Based on the same 1.3″ HF driver, 3″ MF driver, and the same amplifier block as the SCM200ASL Pro, the SCM300ASL employs larger 15″ bass drivers and a larger 300 litre enclosure to deliver even higher maximum volume (121dB/1m), with extended bass and increased transient headroom.  The speakers may be stand or soffit mounted.  The entire system, including all drivers and electronic components, are all hand-crafted and assembled in house by ATC in the UK.

ATC P4 Amplifiers

A pair of SCM300ASL’s includes a pair of outboard rack-mountable P4 amplifiers, one for each speaker.  The P4 is a 4 channel, 3-way, class A/B amplifier with 850w total output.  There are dedicated amplifers for the HF and MF drivers, with a third amp driving the pair of Super Linear LF drivers.  The P4 also features fast FET soft limiting driver protection, 4th order active crossovers with phase correction, and triple fan cooling vented at the rear.  The P4 is rack-mountable in a standard 19″ width requiring 5U of rack space.  Locking multi-pin speaker cables are included at a standard 5m length but can be made to order at any desired length.  The entire system is optimized at ATC for the speaker cable length.

Remote Operation

Stand-by control and status indication via remote for the P4 amplifier is catered for by the inclusion of a 5-pin DIN connector on the rear panel. ATC does not supply a remote operation unit, but the connections required to make use of this function are described in the user manual.



SCM300ASL Pro Brochure (PDF)

P4 Amplifier Manual (PDF)


Max Continuous SPL: 121dB
Cutoff Frequencies (-6dB): 25Hz, 20kHz (free standing) 20Hz, 20kHz (soffit mounted)
ATC Tri-Power: 2@275W LF/1@200W MF/1@100W HF (per speaker)
Power Amplifier: Pair of outboard ATC P4 Amplifiers included, 19" rack mountable 5U
Crossovers: 380Hz, 3.5kHz; 4th order; active, in ATC P4 amps
LF Drivers: Dual 15" ATC custom built SL driver
MF Driver: Single 3" ATC custom SL mid-dome, wave guide loaded
HF Driver: Single 1.3" dome tweeter, wave guide loaded
Horizontal Dispersion: ±80°, Coherent
Vertical Dispersion: ±10°, Coherent
Input Connectors: Balanced Line Level XLR
Soffit Mountable: Yes
Cabinet: Wood/Black Ash
Speaker Cables: ATC Locking Multi-Pin included (5m standard length, custom length available to order)
P4 Amp Actual Weight: 88.2lbs
P4 Amp Shipping Weight: 110.5lbs in crate
P4 Amp Shipping Dimensions: 25"x23"x12" in crate
Speaker Actual H/W/D in inches: 34.8/36.4/18.7
Speaker Actual Weight: 308lbs
Speaker Shipping Weight: 308lbs in crate
Speaker Shipping Dims: 40"x40"x26" in crate
(Speaker stand not included)