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.

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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:

1. Find problem frequencies (boost, sweep, identify)
2. Cut problems (narrow Q)
3. 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

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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)

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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

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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

1. Get balance right in mono
2. Check phase relationships
3. Add stereo width last
4. Always reference in mono

Static Mix Workflow

1. Faders only: Get rough balance
2. Pan: Create space left/right
3. EQ: Carve frequency space
4. Compression: Control dynamics
5. Reverb/Delay: Add depth
6. Automation: Movement and interest

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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

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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

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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)

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References

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