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ATC C4 MkII Subwoofer


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Ex VAT: £3,325.00

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Condition: Brand new in original retail packaging

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Warranty length 6 Years
Brand ATC Speakers

Tech Specs

- Acoustic Specifications
- Drive Unit – Bass - 1 x SS75-314SC 8Ω
- Low Frequency Cut-off - 22Hz (-6dB, half space, low pass filter set at 80Hz)
- Low Pass Filters - 50Hz, 65Hz, 80Hz, 320Hz. (-6dB, 4th order Linkwitz Riley)
- MaxSPL - 10dB continuous, 116dB peak (IEC Weighted Pink Noise, 1m, half space, low pass filter @ 80Hz)
- Sensitivity - +4dBu ref. 88dBC (single channel driven, Gain +6dB, Level 0dB, pink noise, lowpass filter @ 80Hz)
- Electronic Specifications
- Amplifier type - Grounded Source MOSFET based Class A-B, convection cooled
- Output Power - 300W into 8Ω
- THD+N - <0.003%/-90dB, at 100Hz, 300W into 8Ω over 90kHz bandwidth
- Balanced Inputs - 2 x Rear Panel Mounted Female XLR, pin 2 hot
- Balanced Outputs - 2 x Rear Panel Mounted Male XLR, pin 2 hot
- Power Consumption - Idle 8W/14VA. 1/8th Power 170W/230VA. Full Power 500W/600VA
- Physical Specifications
- Dimensions: (H x W x D) - 568 x 465 x 519mm Heatsink protrudes a further 40mm
- Net Weight - 42kg
- 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.
- Available with High Gloss over veneer (Premium Option)

Product Description

The ATC C4 MkII Subwoofer is a professional standard subwoofer that is built without compromise. It delivers amazing bass and has many high-end features. Moreover, it uses one of ATC's renowned 12” low-distortion drivers. Unusually, it also uses a Class A/B amplifier that is MOSFET-based. The unit outputs 300 watts and has adjustable filter settings. This unit will add a whole new dimension to movies and music.

Class A/B amplifier

Unlike most subwoofers, the ATC C4 MkII Subwoofer has a class A/B amplifier. Most subwoofers use Class D amplifiers for high power and efficiency. However, there can be some compromises with sound quality. Consequently, the ATC C4 MkII Subwoofer uses a liner Class A/B amplifier. Additionally, the high output power of 300 watts requires a good cooling system, as a result, this unit has a convection-based cooler.

What is Class A/B?

Class A was the original configuration used for amplifiers. It featured a single output device which was originally a valve. The sound quality was excellent but this configuration is very power-hungry, as the device is always passing a current. Consequently, Class B was developed.

Class B uses two or more output devices that are biased off unless there is a signal present. However, there can be crossover distortion, as the devices switch over on each half-cycle of the audio signal. As a result, Class A/B was developed. This uses sophisticated biasing to operate as Class A at low powers and Class B at higher powers.

Variable low pass filter

The ATC C4 MkII Subwoofer has various settings that allow it to be matched to your main speakers. The first of which is low pass filters at 50Hz,65Hz,80Hz, and 320Hz. This setting is used to match the bass cut off frequency of your main speakers. There is also a gain switch that can add a boost of =6db or +10dB. There is also a manual level control and a phase control. The phase switch is used to match the phase of your main speakers. If this is incorrect the subwoofer will work against your main speakers.

Connecting a subwoofer

Connecting a subwoofer can be complicated as there are many possible configurations and amplifier setups. The ATC C4 MkII Subwoofer is a high-end unit with two 3-pin balanced XLR inputs. These are intended to be used with amplifiers that have pre-out connectors, one for each channel. The signal is then mixed to create a mono signal. Additionally, two or more units can be used with amplifiers that have a sub-output and an LFE (Low-Frequency Effects) output.

Who are ATC?

ATC has a no-compromise policy when it comes to building speakers and they started in the professional studio market. The company began in 1974 with the 12″ PA75-314 driver. This unit soon gained a reputation for low distortion and a higher output than any other driver on the market. In the 1990s they launched a range of audiophile electronics including preamps and power amps that are designed for superior no-compromise performance.

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0121 224 7350/7351

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