What Is an Audio Mixer?
Updated Nov 12, 2026 · By 
Jonah Mercer · Editorial policy
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An audio mixer takes several sound sources and blends them into one output, with a volume control for each. Each channel has its own gain and level controls, so you can balance microphones and line sources before they reach speakers or a recorder. It makes no sound on its own; it shapes and combines the signals plugged into it.
What the channels do
Each channel takes one sound source, such as a microphone or a line source, and gives it its own gain, equalization and level controls. Gain sets how strong the incoming signal is, equalization adjusts the tone of that channel, and the level control sets how loud the channel sits in the mix. The Behringer XENYX X2442USB has 24 input channels, so it can take 24 sources at once, and its 4/2-bus layout sends the mixed signal to its outputs.
Inputs, outputs and buses
Microphones plug into XLR inputs, and line sources use 1/4-inch jacks. Some mixers send 48V phantom power up the XLR cable to power condenser microphones, while dynamic microphones do not need it. The mixed signal leaves through the main outputs to speakers or a recorder, and a bus groups channels together so they can be sent to one output at once. The Behringer XENYX X2442USB also has a USB audio interface, so it can send audio to a computer over a USB Type B connection.
Built-in effects and equalization
Many mixers add effects and equalization to the signal on its way to the outputs. Equalization controls on each channel adjust the balance of low and high frequencies in that channel, and a built-in effects processor can add effects to a channel or to the whole mix. The Behringer XENYX X2442USB has British EQ on its channels and a 24-bit multi-FX processor with an LCD display, plus XENYX mic preamps and compressors on its inputs.
Why some listings here are not audio mixers
The Custom Shop Body Filler Mixing Board is a reusable board with three plastic spreaders for automotive body fillers, putties and glazes. The Custom Shop Multi-Layered Disposable Paper Body Filler and the KREFINISH Body Filler Mixing Board Disposable Paper are paper sheets for mixing body filler, and the KREFINISH board also includes a plastic spatula scraper. Check the product type in the listing before you buy, so the mixer you order matches the job.
What you need
Behringer XENYX X2442USB Premium 24-Input 4/2-Bus Mixer
A 24-input mixer with XENYX mic preamps, compressors, British EQ and a 24-bit multi-FX processor, plus a USB audio interface.
- Mixer channels / decks: 24
- Built-in effects / amp models
Custom Shop Body Filler Mixing Board
A reusable body filler mixing board with three plastic spreaders for automotive body fillers, putties and glazes, not an audio mixer.
Custom Shop Multi-Layered Disposable Paper Body Filler
A pack of 100 disposable paper mixing sheets for automotive body fillers and glazes, not an audio mixer, with a fresh sheet ready after each used sheet is removed.
KREFINISH Body Filler Mixing Board Disposable Paper
A disposable paper mixing board with 100 sheets for body filler, epoxy and glaze mixing, not an audio mixer, plus a plastic spatula scraper.
These come from our ranked list Best Mixing Board, which compares them spec by spec.
Frequently asked questions
What is the difference between a mixer and an amplifier?
A mixer blends several sound sources into one output with a level control for each channel. An amplifier takes one signal and makes it louder so it can drive speakers. A mixer does not drive speakers on its own.
Do I need a mixer to record a microphone?
No. A microphone can plug straight into an audio interface or a recorder with a mic input. A mixer helps when you have several sources to balance at once, or when you want equalization and effects before the signal is recorded.
What does 48V phantom power do?
48V phantom power is a supply a mixer or interface sends up a balanced XLR cable to power a condenser microphone. Dynamic microphones do not need it, and a standard dynamic mic is not affected when phantom power is on.
Ranked audio mixers lists
More how-to guides
Product details come from each Amazon listing and can change. Check the listing before you buy.