Hertz DBX 30.3 12" 4-Ohm Subwoofer Enclosure

The Hertz DBX 30.3 is a passive 12-inch subwoofer enclosure designed to add low-frequency output to a car audio system without requiring a custom-built box. Its factory enclosure helps simplify a bass upgrade where available trunk or cargo space is limited. It is intended for use with an external amplifier matched appropriately to its 4-ohm load and 250-watt continuous power rating.

This enclosure is suited to listeners who want a dedicated bass channel to support full-range door speakers or a factory head unit with added amplification. The 12-inch driver is designed for bass reproduction from 28 to 300 Hz, covering deep low-end content as well as upper-bass impact. With a rated sensitivity of 91 dB SPL, it can be integrated into systems that prioritize efficient output from moderate amplifier power.

The DBX 30.3 uses a polypropylene cone with mica injection, a material combination selected for a rigid diaphragm structure. Its cone also features deep surface ribbing to increase rigidity, while the butyl-rubber surround supports driver excursion. A high-density-flux ferrite magnet and 1.5-inch voice coil form the motor system behind the enclosed driver.

Hertz builds the enclosure from thick MDF to provide a rigid cabinet structure for the installed subwoofer. The rear panel is angled to help reduce internal back-wave reflections and to make placement easier in a vehicle. High-current plated terminals provide the connection point for speaker wire from an external amplifier.

At 19 inches wide, 8.9 inches deep, and 13.5 inches high, the DBX 30.3 offers a compact factory-enclosure format for a 12-inch subwoofer. It can serve as the bass foundation in an entry-level or moderate-power upgrade system. Pair it with a stable amplifier that delivers power suitable for a 4-ohm, 250-watt continuous subwoofer load, then set crossover and gain controls carefully during installation.

Key Features

• 12-Inch Subwoofer: Provides dedicated low-frequency reinforcement in a prebuilt enclosure.
• 250-Watt Continuous Rating: Supports amplifier matching for sustained bass playback.
• 4-Ohm Impedance: Works with amplifiers rated for a 4-ohm subwoofer load.
• Polypropylene Mica Cone: Combines a rigid cone structure with mineral reinforcement.
• Thick MDF Cabinet: Creates a rigid enclosure structure for the installed driver.
• Angled Rear Panel: Helps fit the enclosure against vehicle interior contours.

Design & Installation

The DBX 30.3 combines a thick MDF cabinet with an angled rear wall and a high-density-flux ferrite motor. Its polypropylene cone with mica injection, deep cone ribbing, and high-excursion butyl-rubber surround are designed as part of the installed driver system. The enclosure uses high-current plated terminals for its speaker-level connection from an amplifier.

Mount the enclosure securely on a stable vehicle surface so it cannot move during driving, and leave room around the terminal area for wiring. Connect it to an external amplifier that is compatible with a 4-ohm load and configured for the subwoofer's 250-watt continuous rating. Use the amplifier's low-pass crossover and gain settings to blend the enclosure with the vehicle's main speakers rather than using it as a full-range speaker.