Hertz CS 250 S4 10" 4-Ohm Car Subwoofer

The Hertz CS 250 S4 is a 10-inch passive car subwoofer designed to add dedicated low-frequency output to an aftermarket audio system. It uses a single 4-ohm voice coil and handles up to 300 watts RMS continuous power. This makes it a suitable choice for systems that need bass reinforcement without requiring an unusually large enclosure.

This subwoofer is intended for listeners building or upgrading a car audio system with a compatible external amplifier. Its 4-ohm configuration works with amplifiers designed to drive a 4-ohm subwoofer load. The CS 250 S4 can also be used in multi-subwoofer installations when the amplifier and final wiring load are properly matched.

Hertz specifies 300 watts continuous power handling, 600 watts peak power handling, and 84 dB sensitivity. The driver has a 30 Hz free-air resonance frequency and 12.5 mm of Xmax. These characteristics support low-frequency reproduction in a properly designed enclosure.

The CS 250 S4 uses a polypropylene cone and a high-density flux ferrite magnet assembly. Its 35 mm voice coil is wound in six layers of pure copper on a high-temperature glass-fiber former. Hertz also uses fluid-dynamic optimization and FEM-developed cone and dust-cap geometry intended to reduce distortion during higher-excursion operation.

For enclosure design, Hertz provides a sealed-box recommendation starting at 16 liters (0.57 cubic feet). The specified compact sealed enclosure uses a 231 mm mounting hole and 19 mm wood. Solid push terminals accept cable up to 8 AWG, helping simplify wiring in single- or multi-subwoofer systems.

Key Features

• 300 W RMS Handling: Supports amplifier matching around its 300-watt continuous power rating.
• 4-Ohm Single Voice Coil: Provides a straightforward load for compatible mono or bridged amplifiers.
• 10-Inch Driver: Adds dedicated bass output while fitting a compact sealed enclosure design.
• Polypropylene Cone: Uses a durable cone material engineered for low-frequency operation.
• 12.5 mm Xmax: Provides linear excursion capability for bass reproduction at higher output levels.
• 8 AWG Push Terminals: Accepts substantial speaker cable without separate terminal hardware.

Design & Installation

The CS 250 S4 combines a polypropylene cone with a high-density flux ferrite magnet, a six-layer pure-copper voice coil, and a high-temperature glass-fiber coil former. Its magnetic assembly includes rubber protection, while the mounting gasket is made from high-strength ABS plastic. An optional Hertz CG 250 metal-mesh grille can be fitted for driver protection and finishing.

Plan for a 231 mm (9.09-inch) mounting cutout and 115 mm (4.53-inch) mounting depth, while allowing additional clearance for the overall driver depth. Hertz provides a sealed enclosure design of 16 liters (0.57 cubic feet), with 19 mm (0.75-inch) wood and external dimensions of 385 x 385 x 180 mm. Use an amplifier compatible with a 4-ohm load, set gain appropriately for the subwoofer's 300-watt RMS rating, and follow the recommended crossover settings for the selected enclosure.