Hertz HMR 20 Marine Digital Media Receiver

The Hertz HMR 20 is a marine-grade digital media receiver designed to bring AM/FM radio, Bluetooth streaming, USB playback, and auxiliary-device connectivity to a boat audio system. Its IP66-rated front panel is intended for exposed helm and console installations where water and outdoor conditions are a concern. The large color display and physical controls provide a direct way to manage sources and volume while underway.

This receiver is suited to boat owners building or updating a 12-volt marine audio system with up to four 4- to 8-ohm speakers. Its internal amplifier is CEA rated at 22 watts RMS per channel into 4 ohms, with a stated maximum output of 50 watts x 4 at 4 ohms. Separate zone controls help adapt playback levels for different listening areas on the vessel.

The HMR 20 supports two independently controlled audio zones through dedicated stereo RCA line outputs for Zone 1 and Zone 2. A separate subwoofer RCA output is also provided for adding an external marine amplifier and powered subwoofer system. Per-zone bass, treble, balance, loudness, zone naming, and maximum-volume settings support practical system tuning.

A 3-inch color TFT IPS display with 640 x 360 resolution provides source, track, station, and voltage information. Bluetooth 5.0 supports wireless audio streaming with compatible A2DP and AVRCP devices, while USB playback supports MP3, WMA, and compatible 16-bit/44.1 kHz WAV files. AM/FM reception includes RDS where available, and the receiver is DAB+ ready when used with the optional Hertz HMB DAB+ module.

The HMR 20 is built for 12-volt negative-ground electrical systems and accepts 10 to 16 volts DC. It includes a battery-voltage gauge, over/low-voltage alert, and over-temperature protection that can mute audio output during excessive heat. This makes it a flexible source unit for new marine installations or for replacing an older radio with modern streaming and multi-zone capability.

Key Features

• Two-Zone Audio Control: Independently adjust listening levels for two onboard areas.
• IP66 Front Panel: Helps protect the front control surface from water exposure.
• Bluetooth 5.0 Streaming: Stream audio wirelessly from compatible Bluetooth devices.
• 3-Inch IPS Color Display: Delivers clear source and playback information at the helm.
• Dedicated RCA Outputs: Supports Zone 1, Zone 2, and subwoofer amplification.
• USB Media Playback: Plays supported music files from compatible USB drives.

Design & Installation

The HMR 20 uses a compact rectangular marine-source-unit layout with a sealed IP66-rated front panel, physical source and zone controls, a rotary volume/select knob, and multicolor button illumination. Hertz specifies a 3-inch color TFT IPS display for readable on-screen information. The manufacturer specifies protection performance for the front panel, but does not identify the receiver's enclosure material.

Installation requires a 122 x 52 mm (4.8 x 2.05 in) mounting opening and 99 mm (3.89 in) of mounting depth behind the panel, plus room for the harnesses and connectors. The receiver is intended for 12-volt negative-ground boats and uses a 15A fuse. Use its amplified speaker outputs for four compatible 4- to 8-ohm speakers, or use the RCA zone and subwoofer outputs when integrating external amplifiers.