ATC C4 Sub Mk2

New ATC C4 Sub Mk2

7 December 2023

ATC’s new C4 Sub Mk2 is a high-performance 12″/300mm active subwoofer, designed to deliver the exceptional levels of performance demanded by audiophiles and film & music lovers alike, and as an ideal partner to ATC’s range of loudspeakers. This subwoofer’s performance and features make it ideally suited to stereo, AV and home cinema applications.

ATC has a rich history of developing loudspeaker systems from component level up and the C4 Sub Mk2 is no different. The subwoofer features a new sub-bass driver, developed by ATC’s R&D team and optimised for reproduction of the lowest four octaves of the audio band.

To best achieve this, it is designed with a 30mm magnetic gap, 50% longer than any other offered by ATC. The long-gap and short-coil configuration takes a long-standing ATC design feature to its limit. Distortion is minimised, while simultaneously delivering the high linear excursion required to generate accurate and dynamic low frequency output.

The C4 Sub Mk2 delivers an extended low-frequency response without employing electronic equalisation, quite unlike many subwoofers available today. Instead, the more elegant combination of exceptional transducer engineering and a marginally larger cabinet volume is used.

C4 Mk2 also features an all-new, class AB, 300W amplifier, hand-built by ATC in the UK and precisely optimised to the requirements of the drive unit, resulting in fast, dynamic bass with minimal colouration.

Two balanced inputs provide connectivity suited to both stereo and AV/home cinema systems plus two balanced outputs provide connections to partnering loudspeakers or to ‘daisy-chain’ multiple subs.

Key Features:

  • High performance sealed box design using 12”/314mm ATC proprietary sub driver
  • Ideal partner to SCM19, SCM20, SCM40, SCM50, SCM100
  • Suitable for use in stereo, AV and home cinema applications
  • On-board 300W convention cooled discrete MOSFET class A/B amp
  • 2 x balanced XLR inputs
  • 2 x balanced XLR outputs (un-filtered/processed)
  • User adjustable gain, low pass frequency, polarity and phase settings

Finish Options:

  • Standard veneers – Cherry, walnut, oak, black ash.
  • Standard finishes – Satin black, satin white
  • Premium veneers – European crown cut walnut, pippy oak, rosewood, burr magnolia, burr poplar
  • High gloss – Piano black, piano white


RRP from £3990

ATC C4 Sub Mk2

The size and performance of the C4 Sub Mk2 make it the ideal partner for a wide range of ATC loudspeakers, from the SCM19 up to and including the SCM100. Multiple subs can be employed to elevate performance, to fill larger rooms and also when partnering with larger models of loudspeakers. Home cinema can be particularly demanding of subwoofers and this new design offers improvements in dynamic range and clarity at higher SPLs.

ATC C4 Sub Mk2 ATC C4 Sub Mk2 ATC C4 Sub Mk2