What audio effects do you need to know for SQA Higher Music Technology, and how do reverb, delay, and the modulation effects (chorus, flanger, phaser) change a sound?
Applying effects: using time-based effects (reverb, delay, echo) and modulation effects (chorus, flanger, phaser, tremolo) and distortion, and knowing what each does and how it is controlled.
Applying effects in SQA Higher Music Technology: time-based effects (reverb, delay, echo) that add space and repeats, modulation effects (chorus, flanger, phaser, tremolo) that add movement, and distortion, with how each is controlled and used on a recorded sound.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
Jump to a section
What this dot point is asking
Effects are added to a captured sound to give it space, movement and character. SQA Higher Music Technology expects you to understand the main effect families, what each does, and how it is controlled, so you can explain why an effect is used and what it achieves. This dot point covers time-based effects (reverb, delay, echo), modulation effects (chorus, flanger, phaser, tremolo) and distortion, plus how effects are applied (insert versus auxiliary send, and the wet/dry balance). A question asks you to name an effect and explain its effect on the sound.
The answer
Effects fall into three groups to know. Time-based effects add repeats and space: reverb is the smooth wash of a room's reflections (set by reverb time and wet/dry); delay (and echo) is distinct, timed repeats (set by delay time, often tempo-synced, and feedback). Modulation effects add movement by combining the signal with delayed or pitch-varied copies: chorus thickens, flanger sweeps with a jet-like whoosh, phaser gives a softer swirling sweep, and tremolo wobbles the volume. Distortion adds harmonics by clipping the signal, from warm overdrive to heavy fuzz. Effects are applied either as an insert (in line on one track) or through an auxiliary send (shared, with a wet/dry balance set by the send). Knowing what each effect does and how it is controlled is the examinable skill.
Time-based effects: reverb, delay, echo
These work by adding the signal back to itself over time.
- Reverb simulates the many overlapping reflections of a sound in a space, heard as a smooth decaying tail. Its main controls are reverb time (decay), pre-delay (the gap before the tail starts), and the wet/dry mix. Reverb places a dry sound in a believable room, hall or plate, and helps separate tracks blend.
- Delay produces one or more distinct, separated repeats of the signal. Controls are delay time (often synced to the tempo, such as a quarter note), feedback (how many repeats), and wet/dry. A short delay thickens; a longer delay adds rhythmic echoes.
- Echo is the broader term for delayed repeats, historically produced by tape echo units; modern delay plug-ins emulate these.
Modulation effects: chorus, flanger, phaser, tremolo
Modulation effects use a low-frequency oscillator (LFO) to vary a parameter over time, adding movement.
- Chorus mixes the signal with slightly delayed and pitch-varied copies, simulating several performers and thickening a sound (common on guitars and backing vocals).
- Flanger mixes the signal with a very short, sweeping delayed copy, producing a strong jet-plane "whoosh" as the delay sweeps.
- Phaser sweeps a series of notches through the frequency spectrum, giving a softer, swirling sweep than a flanger.
- Tremolo varies the volume up and down with the LFO, producing a pulsing or wobbling level.
Distortion
Distortion adds harmonics by clipping the waveform, changing a clean tone into a richer or harsher one. It ranges from gentle overdrive (warmth and edge, as on a pushed valve amp) through distortion to heavy fuzz. It is a defining sound of rock and many electronic styles and is applied for character, not correction.
Applying effects: inserts and sends
How an effect is patched in matters.
- An insert places the effect in line on a single track, processing all of that track's signal (used for distortion, and where the whole sound should be affected).
- An auxiliary (aux) send routes a portion of several tracks to a single shared effect (a reverb or delay), with the send level setting how wet each track is. This saves resources and gives a coherent shared space, and is the standard way to apply reverb and delay.
Examples in context
Mixing a vocal for the assignment, you might send it to a shared reverb with a medium hall and a small wet amount so it has space without washing out, plus a tempo-synced quarter-note delay with two or three repeats for depth on the line ends. Both are on aux sends, so the same reverb and delay serve the backing vocals too and the mix sits in one space.
On an electric-guitar part, you might insert overdrive for warmth and bite, add a touch of chorus to thicken it, and send it to the shared reverb. Each effect is a named tool with a stated purpose, which is exactly the analysis the question paper rewards.
Try this
Q1. What is the difference between chorus and tremolo? [2 marks]
- What the marker wants. Chorus mixes the signal with slightly delayed, pitch-varied copies to thicken it; tremolo varies the volume up and down with an LFO to create a pulse. Both use an LFO but change different things (delay/pitch versus level).
Q2. Why are reverb and delay usually applied on an auxiliary send rather than an insert? [2 marks]
- What the marker wants. A send lets several tracks share one reverb or delay, saving resources and giving a coherent shared space, with the send level controlling how wet each track is.
Q3. What does distortion do to a signal? [2 marks]
- What the marker wants. It adds harmonics by clipping the waveform, changing a clean tone into a richer or harsher one, from warm overdrive to heavy fuzz.
A note on sources
This guide is AI-written and not individually human-reviewed. The effects skills follow SQA's Higher Music Technology course specification (C851 76); verify current detail against the SQA Higher Music Technology documents at sqa.org.uk.
Exam-style practice questions
Practice questions written in the style of SQA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Higher specimen4 marksDescribe two effects you could add to a recorded vocal, and explain the effect each has on the sound. (4 marks)Show worked answer →
An effects question. Two marks for named effects, two for their effect on the sound, so choose ones you can describe precisely.
Reverb is a strong first choice: it adds the reflections of a space (set by decay or reverb time and a wet/dry mix), so a dry close-miked vocal sounds as if it is in a room or hall and blends into the mix rather than sitting isolated. Delay is a strong second: it produces distinct timed repeats of the signal (set by delay time, often synced to the tempo, and feedback for the number of repeats), so the vocal gains depth and rhythmic interest, for example a quarter-note slap that thickens the line.
The discriminator is the effect on the sound (space from reverb, repeats and depth from delay) and naming a control. A weak answer lists effects with no description.
Higher 20193 marksExplain the difference between reverb and delay, and how each is applied to a track. (3 marks)Show worked answer →
A comparison question on the two main time-based effects. Marks reward a clear distinction and how each is used.
Reverb simulates the many overlapping reflections of a sound in a space, heard as a smooth tail that decays; it places a sound in a room or hall and is set by reverb time and the wet/dry balance. Delay produces one or more distinct, separated repeats of the signal at a set time, often synced to the tempo, with feedback controlling how many repeats; it adds rhythmic depth and can thicken a part. Both are commonly applied on an auxiliary send so several tracks can share one effect and the wet/dry balance is controlled with the send level.
A weak answer treats them as the same thing. The point is that reverb is a smooth wash of reflections (space), while delay is distinct repeats (echoes).
Related dot points
- Developing audio capture skills: choosing and positioning microphones, setting input levels and gain, and recording sources cleanly without distortion or noise.
Audio capture in SQA Higher Music Technology: choosing microphone types (dynamic, condenser, ribbon), reading polar patterns, positioning mics, setting gain to avoid clipping and noise, and recording sources cleanly for later processing and mixing.
- Using hardware and software to manipulate audio: editing in a DAW (cutting, copying, comping, fades, crossfades), and correcting timing and pitch (quantise, pitch correction, time-stretching), with sample rate and bit depth.
Editing and manipulating audio in SQA Higher Music Technology: DAW editing (cut, copy, comp, fades, crossfades), timing and pitch correction (quantise, pitch correction, time-stretching), looping, and the meaning of sample rate and bit depth for audio quality.
- Processing audio: using equalisation (EQ) to shape frequency content and dynamics processing (compression, limiting, gating, normalisation) to control level, and knowing what each does and why.
Audio processing in SQA Higher Music Technology: equalisation (EQ) to boost or cut frequency bands and shape tone, and dynamics processing (compression, limiting, gating, normalisation) to control the loud-quiet range, with the key controls (threshold, ratio, attack, release) explained.
- Mixing and sequencing: balancing levels and panning, using MIDI sequencing and virtual instruments, automation, and producing a stereo mixdown, plus an awareness of mastering.
Mixing and sequencing in SQA Higher Music Technology: balancing levels and panning across the stereo field, MIDI sequencing and virtual instruments, automation of parameters over time, the stereo mixdown (bounce), and an awareness of mastering.
- Explaining how technological developments relate to 20th and 21st century music: how recording, amplification, electronic instruments, multitrack, sampling, MIDI, the DAW and digital distribution changed how music was made and heard.
How technological developments shaped 20th and 21st century music for SQA Higher Music Technology: recording and amplification, electric and electronic instruments, multitrack recording, sampling and drum machines, MIDI, the DAW, and digital distribution and streaming, and how each changed musical style.
Sources & how we know this
- Higher Music Technology Course Specification (C851 76) — SQA (2024)
- Music Technology subject page (Higher) — SQA (2026)