Hertz HMD1 Monoblock Subwoofer Class D Marine Amplifier, 500W RMS x 1 @ 4 ohms (78213010)

The Hertz HMD1 is a monoblock subwoofer marine amplifier engineered for demanding boat audio systems. Its Class D architecture and purpose-designed marine construction provide controlled power delivery to compatible loudspeakers, with performance dependent on the connected load and channel configuration.

Key Features

• Class D mono output for subwoofer bass reinforcement
• Low-level RCA and high-level speaker inputs
• Selectable automatic remote-on from amplified speaker signals
• Protective marine-oriented epoxy-coated printed circuit boards
• Salt-fog resistance and thermal/short circuit safeguards

Technical Specifications

• Amplifier type: Class D
• Channel arrangement: Monoblock Subwoofer
• Channels: 1
• Output power ratings:
• 500W RMS x 1 at 4 ohms
• 800W RMS x 1 at 2 ohms
• 1000W RMS x 1 at 1 ohm
• Maximum summed advertised power: 1000W
• Minimum impedance: 1 ohm
• Nominal supply: 11–15V DC; operating range 6.5–17V
• Fuses: 2 x 30A
• Bandwidth: 10–500Hz (-1.5dB)
• Signal-to-noise: 110dBA
• Damping factor: 140 at 1kHz / 4 ohms
• Low-level sensitivity: 0.6 / 2 / 6V selectable
• High-level sensitivity: 2 / 6.5 / 20V selectable
• Dimensions: 243 x 48 x 159mm
• Weight: 1.98kg
• Ingress protection: IP64 per Hertz marine technology listing

Compatibility

• Compatible with marine audio sources and speaker systems that meet the listed electrical input and impedance requirements
• Use 12V nominal electrical configuration; do not substitute a 24V-specific amplifier variant
• Subwoofer channel output is intended for properly matched bass speakers and crossover settings

Installation & System Integration

• Choose conductor size, circuit protection, and battery capacity based on the installed system current draw
• Match each speaker or subwoofer impedance to the manufacturer load ratings, observing all bridging limits
• Mount away from standing water with suitable airflow and secure corrosion-resistant terminations
• Configure gain, filter frequencies, and any digital processing prior to high-volume operation
• 1-ohm operation requires careful wiring and current-demand management; fuse at 2 x 30A as specified