Overview
This lecture introduces audio mixers, explaining their main functions, signal flow, controls, and key features found on both analog and digital models.
Mixer Basics
- A mixer combines, routes, and adjusts multiple audio signals for live sound or recording.
- Mixers have repeated channel strips; learning one means you understand them all.
- There are both analog and digital mixers; core functions remain the same.
Channel Strip & Signal Flow
- Signal enters at the top of the channel strip, flows down through controls to the fader, then to the master section.
- Inputs can be microphone (XLR), line level (keyboard, music player), or instrument (guitar, high-Z).
- Gain (trim) control sets the input level; adjust for optimal signal without overload.
- Fader at the bottom controls channel volume sent to the main mix.
Channel Controls & Processing
- Compressor (if present) reduces dynamic range, making volume more consistent.
- Insert jack lets you add external processors (e.g., hardware compressor).
- Low-cut filter removes unwanted low frequencies (e.g., rumble below 100 Hz).
- EQ section shapes tone with high (treble), mid, and low (bass) frequency controls.
Busing & Routing
- Bus: A path for routing signals to outputs (main, sub, monitor, effects).
- Main bus (left/right) sends mix to speakers or recorder.
- Auxiliary buses: Used for monitors (pre-fader) or effects (post-fader).
- Pan control distributes sound across the stereo field.
Master Section & Outputs
- Master fader controls overall mix volume.
- Control room outputs adjust sound for studio speakers.
- Headphone jack with volume allows private monitoring.
- Phantom power (48V) required for condenser microphones.
- Sub-bus for creating separate sub-mixes.
- Effects return controls returning processed signal (e.g., reverb).
Digital vs. Analog Mixers
- Digital mixers may hide controls in menus but offer the same features as analog mixers.
Key Terms & Definitions
- Mixer — Device for blending and routing multiple audio signals.
- Channel strip — Set of identical controls for each input.
- Gain (Trim) — Adjusts input signal strength.
- Fader — Sliders for adjusting signal output level.
- Bus — Signal pathway for grouping/routing audio.
- Auxiliary (Aux) bus — Output for monitors or effects.
- Compressor — Reduces difference between loud and soft signals.
- Low-cut filter — Removes low frequency noise.
- EQ (Equalizer) — Shapes tonal balance by boosting or cutting frequencies.
- Phantom power — Supplies voltage for condenser microphones.
Action Items / Next Steps
- Practice identifying and adjusting each control on a mixer.
- Review your mixer's manual for specific features (compressors, effects, busing).
- Experiment with routing options, EQ, and effects in a real or virtual mixing environment.