Cheat sheet
Sound Basics: Recording and Mixing
A one-page reference for the sample course.
The signal path
Source→Mic→Preamp→Converter→DAW→Mix→Master→Listener
Ranges
| Human hearing | 20 Hz to 20 kHz (upper limit drops with age) |
| Bass guitar low E | about 41 Hz |
| Tuning pitch A440 | 440 Hz |
| Cymbal shimmer | above 10 kHz |
| Speed of sound | about 343 m/s in air at 20°C |
Decibels (a dB always needs a reference)
- dB SPL: acoustic pressure. dBFS: digital level, with 0 dBFS the maximum.
- +3 dB is 2× the power. +10 dB is about 2× as loud, 3.2× the pressure, and 10× the power.
| Conversation | about 60 dB |
| City traffic | about 85 dB |
| Loud concert | about 100 to 110 dB |
Safe listening exposure (NIOSH)
| Level | Safe time per day |
|---|---|
| 85 dBA | 8 hours |
| 88 dBA | 4 hours |
| 91 dBA | 2 hours |
| 94 dBA | 1 hour |
| 97 dBA | 30 minutes |
| 100 dBA | 15 minutes |
| 103 dBA | about 7 minutes |
The time is halved for every +3 dB. Hair cell damage is permanent.
Gain staging
- Digital clips hard at 0 dBFS. Leave headroom.
- Target peaks around −12 to −6 dBFS.
- Record at the true level, not “hot”. 24-bit gives plenty of room.
- Monitor through headphones to avoid mic bleed.
- Clipping cannot be fixed later: lower the gain and re-record.
Digital audio
- Sample rate: 44.1 or 48 kHz is typical. It must be more than twice the highest frequency (Nyquist).
- Bit depth: 24-bit for recording sets dynamic range and noise floor.
- CD: 16-bit / 44.1 kHz.
Mixing tools
- Level: balance. Pan: stereo position.
- EQ: shape frequencies (cut rumble, add clarity).
- Compression: even out dynamics.
- Reverb/delay: depth and space, often through aux sends.
- Flow: tracks → channel strips → group buses → master bus → DAC.
- Habits: reference track, check in mono, check at low volume, take breaks.
Localization cues
- ITD: time difference, best for low frequencies.
- ILD: level difference, best for high frequencies.
- Pinna filtering: front/back and elevation.
Distribution
- Streaming uses lossy codecs and loudness normalization, so over-loud masters are turned down. Targets change, so check each platform's documentation.
- Vinyl: playing time, bass and stereo low end, and harsh highs are limited.