Audio Engineering Patterns

Technical foundations for audio production and sound design.

Signal Flow Fundamentals

The Audio Chain

Source → Processing → Summing → Output

[Mic/Synth] → [EQ/Comp/FX] → [Mix Bus] → [Master] → [Playback]

Gain Staging

Maintain optimal levels at each stage:

Stage	Target Level	Headroom
Recording	-18 to -12 dBFS	12-18 dB
Processing	-18 to -12 dBFS	12-18 dB
Mix Bus	-6 to -3 dBFS	3-6 dB
Master	-1 to -0.3 dBFS	True peak limit

Rule: If a plugin sounds bad, check your input level first.

Frequency Fundamentals

The Spectrum

Range	Frequency	Character	Instruments
Sub Bass	20-60 Hz	Felt, not heard	Kick, bass, 808
Bass	60-250 Hz	Foundation, warmth	Bass, low vocals
Low Mids	250-500 Hz	Body, mud	Guitars, vocals
Mids	500-2000 Hz	Presence, honk	Vocals, snare
Upper Mids	2-4 kHz	Clarity, harshness	Vocals, guitars
Presence	4-6 kHz	Definition, sibilance	Vocals, cymbals
Brilliance	6-10 kHz	Air, shimmer	Cymbals, strings
Air	10-20 kHz	Sparkle, hiss	Room, breath

EQ Patterns

Subtractive First:

Find problem frequencies (boost, sweep, identify)
Cut problems (narrow Q)
Boost characteristics (wide Q)

Common Problem Areas:

Issue	Frequency	Action
Mud	200-400 Hz	Cut
Boxiness	400-600 Hz	Cut
Honk	800-1000 Hz	Cut
Harshness	2-4 kHz	Cut or dip
Sibilance	5-8 kHz	De-ess or cut

Dynamics Processing

Compression Parameters

Parameter	Function	Typical Range
Threshold	When compression starts	-30 to 0 dB
Ratio	How much compression	2:1 to 20:1
Attack	How fast it engages	0.1-100 ms
Release	How fast it lets go	50-1000 ms
Knee	Soft/hard transition	0-12 dB
Makeup	Compensate for gain reduction	As needed

Compression Archetypes

Style	Attack	Release	Ratio	Use
Transparent	Fast	Auto	2-3:1	Vocals, mix bus
Punchy	Slow	Medium	4-6:1	Drums, bass
Glue	Medium	Slow	2-4:1	Mix bus, groups
Limiting	Fast	Fast	10:1+	Peaks, protection
Pumping	Slow	Fast	High	Creative effect

Sidechain Patterns

Trigger Source → Sidechain Input → Compressor → Target

[Kick] → [SC Input] → [Comp on Bass] → [Ducked Bass]

Use for:

Kick/bass separation
Vocal ducking
Rhythmic pumping
De-essing (high-pass SC)

Spatial Processing

Reverb Types

Type	Character	Use
Room	Small, tight	Drums, guitars
Hall	Large, long	Orchestral, pads
Plate	Dense, bright	Vocals, snare
Chamber	Warm, smooth	Strings, vocals
Spring	Bouncy, lo-fi	Guitars, vintage
Convolution	Realistic spaces	Film, realism
Algorithmic	Controllable	Everything

Reverb Parameters

Parameter	Effect
Pre-delay	Separation from source (20-80ms typical)
Decay/RT60	Length of tail
Size	Room dimensions
Damping	High-frequency absorption
Diffusion	Density of reflections
Mix/Wet	Blend with dry signal

Delay Patterns

Pattern	Timing	Use
Slapback	75-150 ms	Vocals, rockabilly
Doubling	20-50 ms	Width, thickness
Rhythmic	Tempo-synced	Groove, production
Ping-pong	L/R alternating	Width, movement
Ambient	Long, diffused	Atmosphere

Tempo Sync Formula:

ms = 60000 / BPM

1/4 note = 60000 / BPM
1/8 note = 30000 / BPM
1/16 note = 15000 / BPM
Dotted = value × 1.5
Triplet = value × 0.667

Mix Architecture

Bus Structure

                    ┌─────────────┐
                    │  Master Bus │
                    └──────┬──────┘
           ┌───────────────┼───────────────┐
           ▼               ▼               ▼
    ┌──────────┐    ┌──────────┐    ┌──────────┐
    │ Drum Bus │    │Music Bus │    │Vocal Bus │
    └────┬─────┘    └────┬─────┘    └────┬─────┘
         │               │               │
    ┌────┴────┐     ┌────┴────┐     ┌────┴────┐
    │K│S│H│OH│     │B│G│K│Pd│     │Ld│BV│Fx│
    └─────────┘     └─────────┘     └─────────┘

Mix in Mono First

Get balance right in mono
Check phase relationships
Add stereo width last
Always reference in mono

Static Mix Workflow

Faders only: Get rough balance
Pan: Create space left/right
EQ: Carve frequency space
Compression: Control dynamics
Reverb/Delay: Add depth
Automation: Movement and interest

Mastering Fundamentals

Chain Order

EQ → Compression → Saturation → Stereo Enhancement → Limiting

Target Levels

Platform	Target LUFS	True Peak
Streaming (general)	-14 LUFS	-1 dB
Apple Music	-16 LUFS	-1 dB
YouTube	-14 LUFS	-1 dB
Club/DJ	-6 to -9 LUFS	-0.3 dB
Podcast	-16 LUFS	-1 dB
Broadcast	-24 LUFS	-2 dB

Metering

Meter Type	Measures	Use For
Peak	Instantaneous max	Clipping prevention
RMS	Average level	Perceived loudness
LUFS	Perceptual loudness	Streaming compliance
Phase	L/R correlation	Mono compatibility
Spectrum	Frequency content	Balance verification

DSP Fundamentals

Basic DSP Operations

Operation	Effect
Gain	Multiply signal amplitude
Sum	Add signals together
Delay	Time offset (samples)
Filter	Frequency-dependent gain
Convolution	Apply impulse response

Filter Types

Type	Effect	Use
Low-pass (LPF)	Removes highs	Warmth, lo-fi
High-pass (HPF)	Removes lows	Clarity, cleanup
Band-pass (BPF)	Isolates range	Radio, telephone
Notch	Removes specific freq	Feedback, hum
All-pass	Phase shift only	Phasers
Comb	Periodic peaks/notches	Flanging

Common Sample Rates

Rate	Use	Nyquist
44.1 kHz	CD, streaming	22.05 kHz
48 kHz	Video, broadcast	24 kHz
88.2 kHz	High-res (2× 44.1)	44.1 kHz
96 kHz	High-res production	48 kHz

Sound Design Patterns

Synthesis Types

Type	Method	Character
Subtractive	Filter harmonics	Classic analog
Additive	Sum partials	Precise, digital
FM	Modulate frequency	Complex, metallic
Wavetable	Morph waveforms	Evolving, digital
Granular	Micro-samples	Textural, ambient
Physical Modeling	Simulate physics	Realistic
Sampling	Recorded audio	Any source

Layering Strategy

Layer 1: Sub (20-80 Hz) - Foundation
Layer 2: Body (100-400 Hz) - Weight
Layer 3: Character (400-2000 Hz) - Identity
Layer 4: Presence (2-6 kHz) - Cut-through
Layer 5: Air (8-16 kHz) - Sparkle

Movement Techniques

LFO modulation (filter, pitch, amplitude)
Envelope shaping (attack, decay curves)
Automation (any parameter over time)
Randomization (subtle variation)
Sidechain (rhythmic pumping)

References

references/frequency-chart.md - Detailed frequency guide
references/plugin-chains.md - Common processing chains
references/daw-shortcuts.md - DAW workflow tips