微信扫一扫Audio Production
Comprehensive guide for professional audio production across music, podcasts, video, and interactive media.
Audio Fundamentals
The Audio Signal Chain
SOURCE → CAPTURE → PROCESS → OUTPUT
Detailed:
┌─────────┐ ┌─────────┐ ┌─────────┐ ┌─────────┐
│ Source │→→→│ Mic │→→→│ Preamp │→→→│Interface│
│(voice, │ │ │ │ │ │ (A/D) │
│ instr.) │ │ │ │ │ │ │
└─────────┘ └─────────┘ └─────────┘ └────┬────┘
│
▼
┌─────────┐ ┌─────────┐ ┌─────────┐ ┌─────────┐
│Speakers │←←←│ (D/A) │←←←│ Mix │←←←│ DAW │
│Headphone│ │Interface│ │ Master │ │Recording│
└─────────┘ └─────────┘ └─────────┘ └─────────┘
Key Audio Concepts
| Concept | Definition | Standard | | ----------------- | ---------------------------- | ------------------------------- | | Sample Rate | Samples per second | 44.1kHz, 48kHz, 96kHz | | Bit Depth | Dynamic range resolution | 16-bit, 24-bit, 32-bit float | | Bit Rate | Data per second (compressed) | 128-320 kbps (MP3) | | Dynamic Range | Loudest to quietest | ~96dB (16-bit), ~144dB (24-bit) | | Headroom | Space below 0 dBFS | -6 to -18 dB typical |
Frequency Spectrum
20 Hz 20,000 Hz
├───────────────────────────────────────────────────────┤
SUB-BASS │ BASS │ LOW-MID │ MID │ HIGH-MID │ HIGH
20-60 │ 60-250 │ 250-500 │500-2k │ 2k-6k │ 6k-20k
│ │ │ │ │
Rumble │ Warmth │ Body │ Pres- │ Presence │ Air
Feel │ Punch │ Muddiness│ ence │ Harshness│ Sibilance
Decibel Reference Points
dBFS (Full Scale):
0 dBFS ████████████ Digital maximum (clipping)
-3 dBFS ██████████ Peaks (leave headroom)
-6 dBFS █████████ Recommended peak ceiling
-12 dBFS ███████ Average loud signal
-18 dBFS ██████ Recommended recording level
-24 dBFS ████ Conservative level
-60 dBFS █ Noise floor target
Recording
Microphone Types
| Type | Principle | Best For | | ------------- | ---------------- | ------------------------------- | | Dynamic | Moving coil | Loud sources, live, durable | | Condenser | Capacitor | Studio vocals, acoustic, detail | | Ribbon | Thin metal strip | Vintage tone, smooth highs | | USB | Built-in ADC | Podcasts, convenience |
Polar Patterns
CARDIOID FIGURE-8 OMNI
╭─────╮ ╭───╮ ╭─────╮
╭─┤ ├─╮ ╭─┤ ├─╮ ╭─┤ ├─╮
│ │ │ │ │ │ │ │ │ │ │ │
│ │ ● │ │ │ │ ● │ │ │ │ ● │ │
│ │ │ │ │ │ │ │ │ │ │ │
╰─┤ ├─╯ ╰─┤ ├─╯ ╰─┤ ├─╯
╰─────╯ ╰───╯ ╰─────╯
Front pickup Front + Back All around
Recording Levels
Target Peaks: -12 to -6 dBFS
Average Level: -18 to -12 dBFS
Why?
- Leaves headroom for processing
- Matches analog equipment sweet spot
- Prevents digital clipping
- 24-bit has plenty of resolution
Recording Best Practices
- [ ] Set gain before recording (never during)
- [ ] Record at 24-bit minimum
- [ ] Use 48kHz for video, 44.1kHz for music
- [ ] Monitor with headphones
- [ ] Record a few seconds of room tone
- [ ] Check phase when using multiple mics
- [ ] Label takes immediately
Essential Processing
EQ (Equalization)
Types:
- High-pass filter (HPF): Removes low frequencies
- Low-pass filter (LPF): Removes high frequencies
- Bell/Peak: Boost or cut specific frequency
- Shelf: Boost or cut above/below frequency
Common Applications:
┌─────────────────────────────────────────┐
│ Vocal: │
│ HPF at 80-100Hz (remove rumble) │
│ Cut 200-300Hz (reduce mud) │
│ Boost 3-5kHz (presence) │
│ Shelf boost 10kHz+ (air) │
├─────────────────────────────────────────┤
│ Kick Drum: │
│ Boost 50-80Hz (sub) │
│ Cut 300-400Hz (boxiness) │
│ Boost 3-5kHz (attack/click) │
├─────────────────────────────────────────┤
│ Electric Guitar: │
│ HPF at 80Hz │
│ Cut 400-600Hz if muddy │
│ Boost 2-4kHz (bite) │
└─────────────────────────────────────────┘
Compression
Parameters:
┌────────────────────────────────────────────────┐
│ Threshold: Level where compression starts │
│ Ratio: Amount of compression (4:1, 8:1, etc.) │
│ Attack: Time to engage (fast=punch, slow=body)│
│ Release: Time to disengage │
│ Knee: Hard (sudden) or soft (gradual) │
│ Makeup Gain: Restore lost volume │
└────────────────────────────────────────────────┘
Common Settings:
┌─────────────────────────────────────────┐
│ Vocals: 3:1-4:1, medium attack/release │
│ Drums: 4:1-8:1, fast attack │
│ Bass: 4:1, medium attack │
│ Mix Bus: 2:1-3:1, slow attack, 1-3dB GR│
└─────────────────────────────────────────┘
Reverb
| Type | Character | Use | | ----------- | --------------- | ------------------- | | Room | Small, tight | Natural ambience | | Hall | Large, spacious | Orchestral, ballads | | Plate | Bright, smooth | Vocals, snare | | Spring | Vintage, boingy | Guitar, lo-fi | | Chamber | Warm, dense | Natural depth |
Key Parameters:
- Pre-delay: Time before reverb (50-100ms for vocals)
- Decay/RT60: How long it lasts
- Damping: High-frequency absorption
- Size: Room dimensions
- Mix/Wet-Dry: Balance with original
Delay
| Type | Application | | -------------- | ------------------------------ | | Slapback | 50-150ms, rockabilly, presence | | Stereo | Different L/R times, width | | Ping-pong | Alternating L/R, interest | | Tempo-sync | 1/4, 1/8 notes, rhythmic |
Mixing
Gain Staging
Signal Flow Levels:
┌─────────────────────────────────────────┐
│ Input: -18 dBFS (sweet spot) │
│ ↓ │
│ Plugin 1: Output matches input level │
│ ↓ │
│ Plugin 2: Output matches input level │
│ ↓ │
│ Fader: Unity (0 dB) ideally │
│ ↓ │
│ Bus: -12 to -6 dBFS peaks │
│ ↓ │
│ Master: -6 dBFS peaks (before limit) │
└─────────────────────────────────────────┘
Panning Guidelines
Stereo Field:
Hard L L L-C CENTER R-C R Hard R
│ │ │ │ │ │ │
│ │ │ │ │ │ │
Rhythm Gtr1 Keys1 Vocal Keys2 Gtr2 Rhythm
Gtr BVox1 Bass BVox2 Gtr
Kick
Snare
Common Positions:
- Center (0): Lead vocal, bass, kick, snare
- Slight L/R: Main instruments, harmonies
- Wide L/R: Rhythm guitars, stereo keys
- Hard L/R: Doubled parts, effects
Frequency Balancing
Making space (subtractive EQ approach):
┌────────────────────────────────────────────┐
│ Kick: Boost 60Hz │ Cut from Bass here │
│ Bass: Boost 80-100 │ Cut from Kick here │
│ Gtr: Owns 1-3kHz │ Cut vocal slightly │
│ Vocal: Boost 3-5kHz │ Cut guitar slightly │
└────────────────────────────────────────────┘
Each element should have its own frequency "home"
Mix Bus Processing
Typical Chain:
1. Subtle EQ (tonal shaping)
2. Light compression (2:1, 1-3dB GR)
3. Stereo enhancement (if needed)
4. Limiter (only for reference bounce)
Keep mix bus processing minimal!
Leave headroom for mastering.
Mastering
Mastering Goals
- Tonal Balance: Even frequency response
- Dynamics: Appropriate loudness/dynamics
- Stereo Image: Width and mono compatibility
- Translation: Sounds good everywhere
- Format: Prepare for distribution
Loudness Standards
| Platform | Target | Measurement | | ------------------ | -------------- | ----------- | | Spotify | -14 LUFS | Integrated | | Apple Music | -16 LUFS | Integrated | | YouTube | -14 LUFS | Integrated | | Broadcast (US) | -24 LUFS | Integrated | | Broadcast (EU) | -23 LUFS | Integrated | | CD | -9 to -12 LUFS | Integrated |
Mastering Chain (Typical)
1. Reference Import
└─→ Compare to commercial releases
2. EQ (Linear Phase)
└─→ Broad adjustments only
3. Multiband Compression
└─→ Control specific bands
4. Stereo Width
└─→ Enhance or narrow
5. Limiting
└─→ Final loudness, prevent clipping
6. Dither (if needed)
└─→ 16-bit conversion only
Podcast Production
Recording Setup
Recommended Signal Chain:
Mic → Audio Interface → DAW
Equipment Tiers:
┌─────────────────────────────────────────┐
│ Budget: USB Mic (Blue Yeti, AT2020) │
│ Mid: SM7B + Cloudlifter + Interface│
│ Pro: Large diaphragm condenser │
│ + high-end preamp │
└─────────────────────────────────────────┘
Podcast Processing Chain
1. Noise Reduction
└─→ Remove room noise, hum
2. De-essing
└─→ Tame harsh "s" sounds
3. Compression
└─→ Even out volume (3:1-4:1)
4. EQ
└─→ HPF at 80Hz, presence boost
5. Limiter
└─→ Catch peaks, -1 dBFS ceiling
Target: -16 LUFS (mono), -19 LUFS (stereo)
True Peak: -1 dBTP
Podcast Export Settings
Standard:
- Format: MP3 or AAC
- Bitrate: 128 kbps (mono), 192 kbps (stereo)
- Sample rate: 44.1 kHz
High Quality:
- Format: AAC
- Bitrate: 256 kbps
- Sample rate: 48 kHz
Chapters: Use ID3 tags for chapter markers
Artwork: 3000x3000 minimum, JPG or PNG
Sound Design
Creating Sounds
Approaches:
1. Recording: Capture real sounds (foley)
2. Synthesis: Create from oscillators
3. Sampling: Manipulate existing sounds
4. Processing: Transform through effects
5. Layering: Combine multiple sources
Synthesis Types
| Type | Method | Sound Character | | --------------------- | -------------------- | --------------------- | | Subtractive | Filter oscillators | Classic analog | | FM | Frequency modulation | Metallic, bells | | Wavetable | Morphing waveforms | Modern, evolving | | Granular | Tiny sound particles | Texture, pads | | Additive | Stack sine waves | Precise, organs | | Physical Modeling | Simulate physics | Realistic instruments |
Layering Formula
Sound Design Stack:
┌─────────────────────────────────────┐
│ TOP: High frequencies (air, presence)│
│ MID: Character, tone │
│ LOW: Foundation, weight │
│ SUB: Felt, not heard (20-60Hz) │
│ TRANSIENT: Attack, punch │
└─────────────────────────────────────┘
Process each layer separately, combine at end.
DAWs (Digital Audio Workstations)
| DAW | Strengths | Platform | | ---------------- | ---------------------------- | -------- | | Pro Tools | Industry standard, editing | All | | Logic Pro | Complete package, Apple | macOS | | Ableton Live | Live performance, electronic | All | | FL Studio | Beat making, workflow | All | | Reaper | Customizable, affordable | All | | Cubase | MIDI, composition | All | | Studio One | Modern workflow | All | | Audacity | Free, simple editing | All |
File Formats
| Format | Type | Quality | Use | | -------- | ------------ | -------- | ------------------- | | WAV | Uncompressed | Lossless | Production, archive | | AIFF | Uncompressed | Lossless | Mac production | | FLAC | Compressed | Lossless | Archive, audiophile | | ALAC | Compressed | Lossless | Apple ecosystem | | MP3 | Compressed | Lossy | Distribution | | AAC | Compressed | Lossy | Streaming, Apple | | OGG | Compressed | Lossy | Games, open source |
Export Specifications
For Mastering:
- Format: WAV
- Bit depth: 24-bit (or 32-bit float)
- Sample rate: Match session (typically 44.1/48kHz)
- Headroom: -6 dBFS peaks
For Distribution:
- Format: WAV or FLAC (lossless)
- Bit depth: 16-bit (with dither)
- Sample rate: 44.1 kHz
- Loudness: Platform target LUFS
Best Practices
DO:
- Record at proper levels (-18 dBFS average)
- Use reference tracks
- Take breaks (ear fatigue is real)
- Check mono compatibility
- Use subtractive EQ first
- Process in series, not parallel (usually)
- Save project versions regularly
- Export stems for backup
DON'T:
- Record with processing (usually)
- Mix at high volumes
- Over-compress everything
- Solo instruments too long
- Trust only one playback system
- Rush the mixing process
- Forget to dither (16-bit only)
- Master your own mixes (ideally)
Quality Checklist
Pre-Export
- [ ] Gain staging correct throughout
- [ ] No clipping or distortion
- [ ] Phase issues resolved
- [ ] Mono compatibility checked
- [ ] Low-end translation verified
- [ ] High frequencies not harsh
Final Check
- [ ] Listen on multiple systems
- [ ] Check in car, phone, earbuds
- [ ] Verify format specifications
- [ ] Confirm LUFS target met
- [ ] True peak below -1 dBTP
- [ ] Metadata correctly embedded