JL Audio Premium Hidden Marine Source Unit (Built-In Amplifier) (MM55-HR)

Premium Hidden Marine Source Unit with Built-In Amplifier (MM55-HR) (010-03372-00)

Introducing the JL Audio MediaMaster MM55HR: a premium hidden marine source unit designed for discerning boat-owners who demand top-tier audio performance and seamless integration.

Engineered for challenging marine environments and built to deliver outstanding sound, this unit offers exceptional features delivered with style and substance.

Key Features & Benefits:

• Hideaway design: Unlike traditional receivers with front-panel screens and controls, the MM55-HR is built as a compact, behind-the-scenes unit that mounts out of sight—ideal for a clean helm or custom integration. 
• Certified NMEA 2000® network connectivity: Control the unit via your compatible multi-function display (MFD) from brands like Garmin®, Lowrance®, Raymarine®, or Simrad®. For full dedicated control, a compatible remote controller (like the MMR-40) is also supported (sold separately). 
• Robust built-in amplifier: Delivers 100 watts of power (25 watts RMS × 4 channels) to efficiently drive speakers in two zones—ideal for helm and cockpit or cabin and deck configurations. 
• Three separate audio zones with nine-channel 4-volt preamp outputs: Each zone includes a dedicated subwoofer output, independent tone, volume, bass/mid/treble, high-pass/low-pass crossover filters, volume limit settings and customizable zone naming (e.g., Bow, Helm, Cabin). Control zones together or individually for full flexibility. 
• Comprehensive source options: Includes digital AM/FM tuner with RDS, built-in DAB+ tuner for European markets, USB 2.0 input (1A charging output) for digital music files, analog AUX input for external devices, and Bluetooth® wireless streaming with Qualcomm® aptX™ codec for enhanced fidelity. 
• Marine-grade construction: With an IP67-rated design, the MM55-HR withstands dust, water immersion (up to 1 m for 30 minutes) and harsh marine conditions—so you get reliable performance whether underway or docked. 
• Compact footprint & install-friendly: The unit measures approximately 7.68″ (W) x 2.28″ (H) x 4.96″ (D) (195 mm x 58 mm x 126 mm) and supports mounting in tight spaces with included harness, making it ideal for custom installation behind the dash or inside a locker. 
• Advanced audio performance: Supports high-pass filters (off/80/100/120 Hz) and low-pass filters (off/60/80/100 Hz) per zone, tone controls for bass/mid/treble, balance, and volume-limit settings—giving you pro-level control over your marine sound.

Why it stands out:
For boat audio enthusiasts and professional integrators alike, the MM55-HR sets the benchmark in hidden marine source units. It integrates seamlessly with modern vessel electronics, offers full multi-zone control, and delivers crisp, high-fidelity sound—even in harsh salt-air conditions.

Whether you’re outfitting a center console, sport-fisher, or luxury cruiser, this unit gives you expansive system capabilities without adding clutter to your helm.

Installation & Usage Tips:

• Pair the unit with a compatible MFD for intuitive control; ensure your NMEA 2000® cables and connectors are correctly configured for full network operation.
• Use the built-in amplifier for zones where you want easier setup, and leverage the pre-amp outputs when adding external amplifiers for premium audio systems.
• Take advantage of zone naming and volume-limit settings to fine-tune the listening experience for different areas of your vessel – for example, limit cabin volume for early mornings, and crank cockpit volume once at sea.
• Use USB input to access music libraries; enable Bluetooth aptX streaming from a compatible smartphone for the best wireless audio fidelity.
• Mount the unit in a dry, ventilated location behind the dash or inside a compartment, being mindful of ventilation and wiring best practices in marine environments.

Specification highlights:

• Operating voltage: 10-16 VDC. 
• Standby current draw: 100 mA; operating current: up to 15 A. 
• Operating temperature range: -4°F to +149°F (-20°C to +65°C). 
• Pre-amp output voltage: up to 4V RMS; selectable fixed at 4V/2V/1V. 
• Support for USB audio formats: MP3, WMA, AAC, WAV. 

Who it’s for: If you’re customizing or upgrading the sound system on your boat, and you need a marine-ready, hidden source unit with premium audio capabilities, multi-zone control and seamless network integration, the MM55-HR is crafted for you.

Whether you’re entertaining on board, cruising offshore or outfitting a commercial vessel, you’ll appreciate the power, flexibility and reliability it delivers.

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Make no compromise on sound or functionality. The MM55-HR brings integrated excellence behind the scenes so you get immersive audio across your boat’s zones — with clean installation, advanced control and rugged marine durability. Unlock your system’s potential with the hidden powerhouse in marine audio.

(MM55HR) (0100337200)
Owner's Manual (pdf)

WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.