The subwoofer category has grown exponentially over the past decade with an extremely wide range of options from almost every high-end loudspeaker manufacturer.
One can spend anywhere from $400 to $50,000 on a single subwoofer and whist that might seem extreme for a component that has a rather limited function — it’s one that can positively or negatively impact the overall sound of your system if you select the wrong one or don’t take the time to experiment with placement.
There is also some merit to the concept of selecting one from the same brand as your primary loudspeakers because the voicing is likely to be very similar.
That is especially true for something like the new ATC C4 Sub MK 2.
Acoustic Transducer Company (ATC) has just introduced the C4 Sub Mk 2 active subwoofer system with a starting price of $5,999 USD depending on the finish. Although the price is rather steep, it’s half the cost of the model it replaces!
The new C4 Sub Mk2 follows the original C4 Sub’s design ethos to naturally enhance low-frequency response across ATC’s line of active/passive speakers (SCM19, SCM20, SCM40, SCM50 and SCM100) without masking details or changing the tonal character in the upper bass/lower mid-range.
It also provides an upgrade path to customers owning smaller loudspeakers and lacking space for larger stereo loudspeakers whilst also strengthening ATC’s options for home theater systems.
Designed to combine the highest standards of driver and electronics engineering in a single system, the C4 Sub Mk 2 deploys the all-new proprietary 12-inch SS75-314SC sub-bass driver with a newly developed 300W class AB amplifier.
Both elements hand-built and installed within a substantial cabinet at the company’s Stroud-based production HQ.
Tip: ATC’s subwoofer line currently consists of the smaller C1 Sub Mk2 ($2,999) and larger C6 Sub ($14,999).
New ATC Sub-Bass Driver
The C4 Sub Mk 2 features the new SS75-314SC sub-bass driver, the first to be purpose-built for an ATC sub-bass system and developed by the R&D team to reproduce the lowest four octaves of the audio band.
In order to achieve this the design exploits ATC’s signature long-gap/short-coil configuration to its natural limits with an exceptionally long 30mm magnetic gap, surrounded by a 6-inch/150mm N48M Neodymium magnet – the most powerful ever assembled by ATC and a first for the company.
In support, the wholly redesigned motor system features a new rubber roll-surround for high excursion capability, a new spider for optimized compliance geometry, and high flow motor venting for low noise and compression.
As well as minimizing distortion, this unprecedented short-coil long-gap configuration ensures the voice coil remains within the motor structure – even at high drive levels – maximizing cooling, reducing power compression, and improving reliability. Turbulent air noise within the driver is minimized by a large, flared vent running through the center of the motor structure, which has the added benefit of increasing voice coil and motor cooling.
Consequently, the C4 Sub Mk2 delivers an extended low-frequency response while avoiding electronic equalization, unlike many subwoofers available today. Instead, the more elegant combination of exceptional transducer engineering and a marginally larger cabinet volume is used. The simplicity of this approach reduces phase shift and group delay, aiding the integration of the sub with the partnering loudspeakers.
In addition, multiple subs can be employed to further elevate performance in larger rooms or when partnering larger loudspeakers. Buffered linkable inputs and outputs make connection of multiple subs easy.
New 300W ATC Amplifier
The all-new 300W class AB design is precisely optimized to the requirements of the new driver, resulting in fast, dynamic bass with minimal coloration. Two balanced line inputs provide connectivity for stereo or AV/home cinema systems while two balanced outputs are available to feed partnering ‘main’ stereo loudspeakers or to ‘daisy-chain’ multiple subs.
Low-pass filters are analogue, 4th order Linkwitz-Riley, with filter frequency options ensuring optimal integration with partnering speakers. In addition, an industry-standard 80Hz low-pass filter and an ‘off’ option (for use with external processing) is joined by a polarity switch, variable 180° phase adjustment and a stepped attenuator over a 21 dB range for precise level matching.
Tip: The previous generation ATC C4 Sub used 450-watt Class G amplifier.
Cabinet
Hand-built and finished at ATC’s cabinet factory and sharing styling with the brand’s ‘Classic’ and ‘Tower’ series loudspeakers, the C4 Sub Mk 2’s 70-liter cabinet employs 25mm/1-inch-thick panels and heavy bracing.
It’s available in standard Cherry, Black Ash, Walnut and Oak real-wood veneers, as well as Satin Black and Satin White finishes, or in premium Rosewood, European Crown Cut Walnut, Burr Magnolia, and Pippy Oak real-wood veneers, with the option of high gloss over veneers and black/white piano lacquers also available.
Comparison
| C1 Sub Mk2 | C4 Sub Mk2 | C6 Sub | |
| MSRP | $2,999 | $5,999 | $14,999 |
| Driver | 314 mm (12”) | 314 mm (12”) | 375 mm (15”) |
| LF Cut Off (-6dB) | 25Hz | 22Hz | 20Hz |
| Max SPL | 103dB | 110dB | 115dB |
| Amplifier output @ 8Ω | 200W | 300W | 450W |
| Amplifier type | Class A/B | Class A/B | Class G |
| User Controls | Gain, Low Pass Frequency, Polarity, Phase | Gain, Low Pass Frequency, Polarity, Phase | Gain, Low Pass Frequency, Polarity, Phase |
| Inputs | Stereo High Level Binding Posts Stereo Line Level RCA/Phono | 2 x Male XLR Footswitch (Input & Thru) | 2 x Male XLR |
| Outputs | Mono Summed Line Level RCA/Phono | 2 x Male XLR | – |
| Height | 450 mm (17.72”) | 568 mm (22.31”) | 624 mm (24.6”) |
| Width | 360 mm (14.17”) | 464 mm (18.25”) | 580 mm (22.8”) |
| Depth | 400 mm (15.75”) | 500 mm (19.69”) | 580 mm (22.8”) |
| Weight | 26.2 kg (57.64 lbs) | 42 kg (92.6 lbs) | 60 kg (132 lbs) |
Pricing & Availability
The ATC C4 Sub Mk 2 subwoofer will be available immediately in standard finishes for $5,999 USD, which includes Cherry, Black Ash, Walnut and Oak real-wood veneers, as well as Satin Black and Satin White.
Premium finishes in Rosewood, European Crown Cut Walnut, Burr Magnolia, and Pippy Oak real-wood veneers are available for an extra $1,000 charge.
A premium high gloss finish and piano black or white can be order for an extra $2,700 – $3,000 per pair over standard pricing.
For more information: lonemountainaudio.com
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