Mackie HM-4 4-Way Headphone Amplifier Mixer

The Mackie HM-4 is a compact 4-way headphone amplifier that lets one stereo source feed four headphones with independent volume control.

The HM-4 is an ultra-compact accessory designed to split a single 1/4" stereo input across four 1/4" headphone outputs without sacrificing control or build quality. Its metal enclosure, included 12V adapter, and dedicated level knobs make it a practical choice for home studios, rehearsal rooms, classroom setups, or collaborative listening sessions. It keeps signal routing simple while giving each listener the ability to set their preferred volume.

How do I connect the HM-4 to my audio setup?

Connecting is straightforward: plug your stereo source into the single 1/4" input and connect up to four headphones to the outputs. Power the unit with the included 12V AC adapter and use the front-mounted volume knobs to set each listener's level independently.

• One 1/4" stereo input accepts line/headphone outputs from mixers, interfaces, or phones (with adapter).
• Four 1/4" outputs for standard headphones—no splitters required.
• Supplied 12V adapter powers the amplifier for consistent performance.

Will the HM-4 affect sound quality or introduce noise?

The HM-4 is engineered to preserve the incoming stereo signal while distributing it to multiple listeners. Its solid metal chassis and dedicated amplification circuitry minimize crosstalk and preserve clarity at reasonable listening levels, though extreme volumes may still be limited by headphone power requirements.

• Individual level pots reduce channel interaction between outputs.
• Rugged construction helps shield electronics from interference.
• Designed for clean splitting of a single stereo source to four outputs.

How portable and durable is this unit for studio or live use?

The HM-4's compact footprint and robust metal housing make it easy to carry and durable enough for frequent use. It fits comfortably on a desk, in a rack case, or inside a gig bag, and the included power supply means you can set it up quickly without hunting for adapters.

• Ultra-compact design occupies minimal desk or stage space.
• Metal chassis withstands regular handling and transport.
• Lightweight enough to add to portable setups without bulk.

What control features does each headphone have?

Each headphone output features its own level control so listeners can personalize volume without affecting others. The front-panel knobs are easy to reach and provide smooth adjustment for rehearsal, tracking, or casual listening.

• Four independent volume knobs—one per headphone output.
• Front-panel placement for quick, tactile control during sessions.
• Simple layout reduces setup time and user confusion.

Who is this for: The Mackie HM-4 suits home producers, small project studios, music teachers, and bands who need a compact, reliable way to share one stereo feed with up to four listeners. If you require portable multi-listening with independent volume control and a tough build, the HM-4 offers a practical, no-frills solution without complex routing.