Portable PA Specifications

Liberty MPB-4500 Portable Sound System

Liberty Sound System The sound system designed to do one thing well: Everything

Liberty is really two sound systems in one. In “Music” mode, it provides rich, full-range music reproduction—the kind you can feel. Flip the switch, and Liberty’s tuned especially for speech projection, concentrating its power to make the voice segment of the sound spectrum carry farther.

Either way, the MOSFET amplifier and high-output speakers provide powerful sound with virtually no distortion. Liberty can handle a crowd of 1,000—double that with a companion speaker (MP-4501) attached. Its easy versatility and durability make it our most popular sound system.

The MPB-4500 is a 50-watt battery-powered sound system that runs 6 to 8 hours on a charge. It is designed for crowds up to 1,000 people with its 117dB of clear sound. Built-in options include a cassette player, wireless receiver, or a combination of both. Liberty is used at the White House for Presidential press conferences, at thousands of schools around the world, at corporate training centers and on every U.S. aircraft carrier. Liberty is rugged, reliable and crystal clear.


  • Project/Music Switch. “Project” emphasizes voice for better clarity, “Music” gives higher fidelity.
  • Switchable to either an efficient voice-projecting system or a full-range music quality system.
  • Handles crowds of 1,000 or more.
  • Accommodates multiple mics, plus CD/Tape input.
  • 50 watt amplifier
  • Two XLR balanced phantom-powered mic inputs, 1/4″ line input, line output, treble and bass controls.
  • 12 volt DC output and 1/4″ speaker output.

Dimensions: 13×22.5×10″(WxHxD)
Weight: Approximately 44 lbs
Supplied with: cables, carrying case