Sound Design Audio Effects and Signal Processing 1 — Questions and Answers
Question 1: What does a compressor do to an audio signal?
- Boosts all frequencies equally
- Reduces the dynamic range by attenuating signals above a set threshold (Correct answer)
- Adds harmonic distortion
- Increases the sample rate
Correct answer: Reduces the dynamic range by attenuating signals above a set threshold
A compressor reduces the dynamic range of an audio signal by turning down the volume of portions that exceed a set threshold by a ratio, making quiet and loud parts more even in level.
Question 2: What is the 'attack' parameter on a compressor?
- The amount of gain reduction applied
- How quickly the compressor responds to a signal exceeding the threshold (Correct answer)
- The output gain added after compression
- The frequency at which compression is applied
Correct answer: How quickly the compressor responds to a signal exceeding the threshold
The attack time on a compressor determines how quickly it begins reducing gain after the input signal crosses the threshold, measured in milliseconds — faster attacks catch transients, slower ones let them through.
Question 3: What type of effect is a 'convolution reverb'?
- A synthesized reverb using algorithms
- A reverb that uses an impulse response recording of a real acoustic space to simulate that space (Correct answer)
- A type of delay effect
- A modulation effect
Correct answer: A reverb that uses an impulse response recording of a real acoustic space to simulate that space
Convolution reverb mathematically convolves a dry signal with an impulse response (IR) — a recording of a real space's acoustic response to a brief burst of sound — to place audio convincingly in that real environment.
Question 4: What is the difference between a 'delay' and a 'reverb' effect?
- Delay only works on high frequencies; reverb only on low frequencies
- Delay creates discrete repeating echoes; reverb simulates dense reflections that blend into a diffuse tail (Correct answer)
- Delay is a time-based effect; reverb is a frequency-based effect
- There is no difference
Correct answer: Delay creates discrete repeating echoes; reverb simulates dense reflections that blend into a diffuse tail
Delay produces distinct, spaced repeating echoes of the original signal, while reverb simulates the complex wash of many closely-spaced reflections from walls, floors, and ceilings that merge into a diffuse tail.
Question 5: What does a 'high-pass filter' do?
- Allows only high frequencies to pass through, attenuating low frequencies below the cutoff (Correct answer)
- Allows only low frequencies to pass
- Boosts high frequencies with a shelf
- Cuts frequencies at a specific band
Correct answer: Allows only high frequencies to pass through, attenuating low frequencies below the cutoff
A high-pass filter (HPF) allows frequencies above its cutoff point to pass through while attenuating (rolling off) frequencies below the cutoff, commonly used to remove unwanted low-frequency rumble from audio.
Question 6: What is 'sidechain compression' used for in sound design and mixing?
- Compressing only the side channels in mid-side processing
- Using one signal (the sidechain input) to trigger compression on a different signal (Correct answer)
- A type of stereo widening compression
- Compressing only frequencies above 5 kHz
Correct answer: Using one signal (the sidechain input) to trigger compression on a different signal
Sidechain compression uses an external signal (e.g., a kick drum) to trigger the compressor on another signal (e.g., a bass guitar), causing the second signal to duck in level each time the trigger fires — creating rhythmic pumping.
Sound Design Audio Effects and Signal Processing 1
What does a compressor do to an audio signal?