Arc Audio X2 650.1 Monoblock Subwoofer Amplifier | 650W | Class D

Power Output

Subwoofer-Optimized Bandwidth

The X2 650.1 has an output bandwidth of 20 Hz to 230 Hz. This is not a limitation: it is an engineering decision. Every watt the amplifier produces is directed at low-frequency content. The amplifier does not attempt to reproduce frequencies outside the subwoofer operating range, which means its power supply and output stage design are optimized for bass reproduction rather than being compromised by full-range requirements. The low-pass crossover is adjustable from 30 to 230 Hz and the subsonic filter runs from 10 to 80 Hz for ported enclosure protection. A bass boost of 0 to 12 dB centered between 30 and 125 Hz is included but should be used sparingly.

Strappable to 1100 Watts

Two X2 650.1 amplifiers can be strapped together in master/slave configuration to deliver 1100 watts RMS into a 4-ohm load. The master amplifier provides all control functions (crossover, subsonic, bass boost, phase, gain) while the slave amplifier bypasses its controls and follows the master's signal. The slave input and slave output connections on each unit use RCA interconnects. This is not a bridging operation in the traditional sense: the X2 650.1 is already a monoblock and cannot be bridged. The strapping function doubles output capacity while maintaining the 4-ohm minimum load on the combined pair.

Balanced Differential Inputs and OEM Integration

The X2 650.1 uses balanced differential inputs compatible with RCA line-level signals, balanced outputs from DSP processors, common-ground speaker-level outputs, and bridged-tied-load (BTL) outputs common to factory amplifiers. Included speaker-level input RCA pigtails incorporate a resistive voltage divider network that reduces the high-voltage output of factory amplifiers to an appropriate level for the X2's differential input stage. This makes the X2 650.1 directly connectable to factory audio systems without an external line output converter in most applications.

The auto-detect turn-on provides two options: DC Detect monitors the RCA input for the DC offset common to factory BTL amplifiers and turns the X2 on when it appears, and Signal Detect turns the amplifier on when an audio signal is present. Either mode eliminates the need for a dedicated remote wire from the head unit, which simplifies factory integration.

Compact Footprint, Installer-Friendly Design

At 9.02 inches long, the X2 650.1 fits in locations that longer monoblocks cannot reach: under seats, behind kick panels, in center console cavities, and in the small trunk areas of compact vehicles. The Level 1 cosmetics use a black steel chassis with a rotatable diamond-cut aluminum badge that can be oriented in 90-degree increments to suit any mounting position. All tuning controls are accessed by removing the top cover, and the amplifier presents a clean exterior during normal operation without exposed knobs or visible controls.

X2 Series Context: 650.1 vs 1100.1 vs 2500.1

The X2 Series monoblock lineup spans three power levels: 650.1 (650W at 1 ohm, 9.02 in), 1100.1 (1100W at 1 ohm, 13.0 in), and 2500.1 (2500W at 1 ohm, 20.92 in). All three share the same crossover, subsonic, bass boost, and control architecture and use the same strapping system. The 650.1 is the right choice for single-subwoofer daily driving builds and compact installations. The 1100.1 suits dual-subwoofer builds and single high-power drivers. The 2500.1 addresses large-format and competition-oriented builds.

Built and Backed

The Arc Audio X2 650.1 carries a 1-year warranty through authorized Arc Audio dealers. Audio Intensity is an authorized Arc Audio dealer. Every unit we sell is brand new current production with full warranty coverage and lifetime tech support.