Audio Arts Production I

FX Processing

Reading and Discussion

• The Future of Music: Credo by John Cage

FX Processing

• Every DAW and software application has slightly different ways of employing FX
• HOWEVER, they all function similarly:
  • Channel assignments (inserts/sends)
  • Busses and groups
  • Master fader or main output
  • Modeled after studios and mixing boards

Plugins

• Plugins can be downloaded and added for expanding features of any DAW
• Categories of plugins:
  • Instrument: synths, samplers, emulators, etc.
  • Audio/FX: filters, reverb, EQ, etc.
• Formats:
  • VST2 and VST3: General for MacOS/Windows/Linux
  • AAX: For Pro Tools Only
  • Apple Audio Units (AU): MacOS - GarageBand and Logic Pro
  • And more!

Common FX and their Params

• Many effects can be used to emulate physical spaces and behaviors, but also as creative modulations in and of themselves.
• Common FX parameters:
  • Assumes Wet/Dry Mix, which is how much of the plugin's effect is mixed with the original audio signal, is often included in most plugins
  • List of common FX and common parameters. Each plugin is unique, but you will likely find these params in each:

Reverb

• Portraying acoustic spaces
• Adding color to sound, like spring reverb
• Params
  • Time: How long reverb lasts
  • Pre-Delay: Time between original sound and start of reverb
  • Size: How big is the space?
  • Damping: How quickly high freqs

Chorus

• Stacking a signal and slightly detuning the stacks
• Gives a fullness/richness to the signal
• Params
  • Rate: Speed of the pitch or delay modulation
  • Depth: Amount of modulation applied to the signal
  • Voices: Number of slightly detuned or decayed copies added to the original
  • Delay Time: Base delay between the original and its copies

Filters

• Allowing isolation and removal of certain frequency bands
• Character of filter can add color to the signal
• Params
  • Cutoff Frequency: Freq at which a filter begins reducing or shaping the signal
  • Resonance (Q): Emphasizes freqs near the cutoff freq

Filters

• Params
  • Slope: How quickly freqs are attenuated beyond the cutoff, often measured in dB per octave
  • Filter Type: Determines which freqs are affected
  • See video link for full description!
• Basics of Filters

Delay

• Play back delayed copies of a signal
• Can also be thought of as echo in some cases
• Params
  • Time: Interval between the original sound and each repeat
  • Feedback: Amount of the delayed signal fed back into the effect to create additional repeats
  • Sync: Synchronizes delay time to tempo or milliseconds

Phaser

• Shifts the phase of an audio signal on itself to create new characteristics
• Params
  • Rate: Speed of the sweeping phase modulation
  • Depth: Range or intensity of the modulation
  • Stages: Number of phase-shifting sections that create moving peaks and notches in the frequency response
  • Feedback: Amount of the output fed back into the effect to emphasize its resonant character

Flanger

• Delay + Phaser
• Params
  • Rate: Speed of the modulated delay sweep
  • Depth: Amount of variation of the delay time
  • Feedback: Amount of output fed back into the effect, intensifying the resonant sound
  • Manual/Base Delay: Sets the starting delay time and influences the effect's tonal character

Compressor

• Reduces dynamic range by lowering signals that exceed a set threshold
• Params
  • Threshold: Level above which compression begins
  • Ratio: Determines how much the signal above the threshold is reduced
  • Attack: How quickly compression responds when the signal exceeds the threshold
  • Release: How quickly compression stops after the signal falls below the threshold
  • Gain: Raises the output level to compensate for volume lost

Compressor: Ratio

• Ratio determines how strongly a compressor reduces signals above the threshold
• Ratio examples
  • 1:1: No compression
  • 4:1: Every 4 dB above the threshold produces 1 dB of output above the threshold
  • 10:1: Every 10 dB above the threshold produces 1 dB of output above the threshold
  • Higher ratios produce stronger compression; very high ratios approach limiting

Compressor: Knee

• Knee
  • Hard Knee: Compression begins abruptly at the threshold
  • Soft Knee: Compression increases gradually around the threshold
• Compressor behavior can vary; some compressors adjust their response based on the incoming audio

Limiter

• Prevents audio peaks from exceeding a set level
• Params
  • Threshold: Level at which limiting begins
  • Ceiling: Maximum target output peak level
  • Release: How quickly the limiter stops reducing gain after a peak
  • Lookahead: Delays the signal internally so the limiter can respond before a peak reaches the output
  • Input Gain: Raises the signal entering the limiter, increasing the amount of limiting

Expander

• Increases dynamic range by making quieter signals quieter relative to louder signals
• Params
  • Threshold: Level below which expansion is applied
  • Ratio: Amt of expansion applied to signals below the threshold
  • Attack: How quickly the processor responds when the signal crosses the threshold
  • Release: How quickly the processor returns to its unprocessed behavior
  • Range: Max amount of gain reduction applied

Noise Gate

• Reduces signals below a set level to minimize unwanted noise
• Params
  • Threshold: Level the signal must exceed to open the gate
  • Attack: How quickly the gate opens when the signal exceeds the threshold
  • Hold: Minimum time the gate stays open after the signal falls below the threshold
  • Release: How quickly the gate closes after the signal falls below the threshold
  • Range: Amount the signal is reduced when the gate is closed

Dynamic EQ

• Adjusts specific frequency ranges dynamically in response to the signal level
• Params
  • Frequency: Selects the frequency range being adjusted
  • Threshold: Level at which the dynamic EQ begins responding
  • Range: Maximum amount of boost or cut applied
  • Q: Determines how narrow or broad the affected frequency range is
  • Attack/Release: Control how quickly the EQ responds and recovers

More coming soon!

• This will be an ongoing list as we work through projects.
• Some to be added...
  • Distortion
  • Tremolo
  • Vibrato
  • What else?!

Group Project 2 Rubric