ATC’s New Super Subwoofer Digs Deep

Editor’s note: This story was updated 11/29/23.

Acoustic Transducer Company (ATC), the pro-leaning U.K.-based firm that bills itself as “manufacturer of the finest audio systems in the world,” today introduced a subwoofer designed to reproduce the lowest four octaves of the audio band.

The new C4 Sub Mk 2 ($5,999) is a high output, low-distortion monster of a subwoofer that uses a combination of “exceptional transducer engineering and a marginally larger cabinet volume” to produce an extended low-frequency response instead of relying on electronic equalization — an approach said to ease speaker integration by reducing phase shift and group delay. The C4 has a specified low-frequency cutoff of 22 Hz and mates a proprietary 12-inch driver with a 300-watt Class AB amplifier in a sturdy enclosure 22 inches tall, 18 inches wide, and almost 20 inches deep.

ATC’s purpose-built SS75-314SC sub-bass driver (yes, it has its own model number) boasts a long-gap/short-coil configuration with an exceptionally long 1.2-inch magnetic gap surrounded by a massive 6-inch neodymium magnet, making it the most powerful motor system ATC has ever built. The assembly includes a large, flared vent that runs through the center of the motor structure to enhance cooling and is designed to ensure the voice coil remains within the motor structure — even at high drive levels — in an effort to maximize cooling, reduce power compression, and improve reliability.

The driver also features a spider optimized for low noise and compression and a cone supported by a rubber roll-surround built to withstand high excursions.

To encourage fast, dynamic bass with minimal coloration, the amplifier is optimized to meet the specific requirements of the driver and equipped with adjustable 4th-order Linkwitz-Riley low-pass filters (with an “off” setting for use with external processing), a polarity switch, a variable 180° phase control, and a level control with a 21 dB range in 1-dB steps for precise level matching. Connections include balanced XLR inputs and outputs (two each).

The cabinet is heavily braced with 1-inch-thick walls and available in numerous standard finishes, including satin black, satin white, and four wood veneer finishes: cherry, black ash, walnut, and oak. Premium rosewood, European Crown Cut Walnut, Burr Magnolia, and Pippy Oak wood veneers are available at extra cost along with the option of high gloss over veneers and black/white piano lacquers. For more information, visit

utopianemo's picture

I’m sorry, did you say 2Hz? As in not 20, but 2?? I’m having an existential crisis over here.

trynberg's picture

"...MONSTER of a subwoofer..."

This thing has a 12-inch driver, extends to 22 Hz, and costs $6,000. The only thing monstrous about it is the horrible performance-to-price ratio. But hey the rear of the subwoofer (which is never seen) has a very nice wood finish and it has horribly-designed Victorian feet as a bonus.

tecoli2976's picture

All of us here in Midland Drywall Contractors is looking forward to the enhanced cooling and reliability benefits it brings.

jeff-henning's picture

Here is all I have to say on the subject… check out the following link and then tell me which subwoofer you would rather have:

Not only is it drastically more powerful in real low end output and offers much less distortion, but it’s $3,000 cheaper.

Let me echo: $5k for a single 12” sub?

Unless this is made with Vibranium, I’m at a total loss for the price.

jeff-henning's picture

It just makes my argument more potent.