Glossary — mixing, mastering, and clinical audio
Assuagement
Assuagement — the reduction in intensity or severity of an unwanted experience (pain, anxiety, grief), often the primary clinical aim of music interventions. In this project it describes the emotional and physiological easing targeted by curated musical materials.
Air
High‑frequency content above ~12 kHz that creates a sense of openness and detail. Commonly enhanced with gentle EQ boosts or exciters to add polish and perceived clarity without raising harshness.
Body
Perceived fullness in the midrange (typically ~200–600 Hz) that gives instruments and vocals weight and presence in the mix. Lack of body can make elements sound thin or distant.
Boomy
An over‑emphasis of low and low‑mid frequencies which produces excessive sustain or rumble (often felt rather than precisely heard). Boomy mixes usually benefit from targeted cuts in the 40–160 Hz region and tighter transient shaping.
Boxy
A constricted, honky quality caused by an excess of energy in the low‑mid band (≈200–800 Hz) that makes sounds lose clarity and feel congested. Surgical mid cuts and careful mic placement normally remedy it.
Chug
A punchy, percussive midrange character often heard in rhythmic guitars or muted riffs; prized in rock/metal for forward‑pushing rhythm but best balanced to avoid masking other mid instruments.
Cloudiness
Excess low‑mid buildup (≈200–500 Hz) that softens transients and reduces separation — similar to 'muddy' but used to describe a diffuse, unfocused density across the mix.
Muddy
A mix condition where low‑mid energy masks detail and intelligibility, causing a lack of clarity; often cured by subtractive EQ and improved instrument separation.
Creaminess
A smooth, rounded tonal balance with pleasant midrange sweetness, frequently achieved with gentle harmonic saturation and warm compression.
Crunchy
A slightly broken‑up, harmonically rich texture produced by overdrive, aggressive saturation, or tight compression — useful for character but can be fatiguing if excessive.
Ratty
A gritty, harsh texture often caused by excessive high‑mid distortion, clipping or poor processing; usually an undesirable by‑product of over‑processing.
Fatiguing
A listening quality caused by repeated exposure often due to excess high‑mid energy or over‑compression, leading to listener discomfort over time.
Fizz
An exaggerated upper high‑mid shimmer (lower treble) that can make cymbals and vocals 'sparkly' but becomes harsh or sibilant when overdone.
Glue
A perceptual sense of cohesiveness between mix elements often achieved with subtle bus compression, balancing, and harmonic blending that makes tracks feel like one piece.
Growl
A low, throaty distortion character used to add weight or grit (commonly on bass or low synths).
Snarl
A higher‑mid aggressive character similar to growl but brighter and more biting; often used on guitars or edgy vocal lines.
Hiss
Non‑musical high‑frequency noise without a defined pitch (tape hiss, electronics). Typically reduced with noise‑reduction tools in post‑production.
Honky / Nasal / Pinched
Midrange emphasis (≈400 Hz–1 kHz) that produces a thin, nasal coloration typically corrected with surgical cuts or bandwidth‑adjusted EQ.
Lift
A deliberate light boost in the very high frequencies (≈10–16 kHz) to impart air and shimmer—apply gently to avoid exaggerated sibilance or harshness.
Presence
An upper‑mid frequency focus (≈2–6 kHz) that helps vocals and lead instruments cut through and remain intelligible in dense mixes.
Punchiness
Sensation of attack and impact produced by transient strength and frequency balance, often shaped with transient designers, compression and EQ.
Pumping
Short bursts of audible level fluctuation caused by a compressor or limiter responding to loud elements; can be intentional (creative) or an unwanted artifact of misconfigured dynamics processing.
Richness
A full, harmonically complex tonality with pleasing overtone content across frequencies, often perceived as 'fuller' sound.
Silkiness
A smooth, delicate treble quality that adds perceived refinement without harshness; often associated with high‑quality analog or subtle processing.
Warmth
A pleasing low/mid emphasis and subtle harmonic coloration that contributes to a comfortable, rounded tonal character.
Subbiness / Subby
Excessive infrasonic or subwoofer-frequency energy (typically <60 Hz) that can cloud mixes and cause imbalance on small playback systems.
For technical details on resonant ringing see Resonant peaks / Ring under Common mixing and signal terms.
- Artifact
- An unintended side effect of processing (aliasing, clipping artifacts, time‑stretch artifacts, etc.).
- Atmos / immersive
- Object‑based or immersive audio formats (Dolby Atmos, Ambisonics) that allow three‑dimensional placement of sounds.
- Attenuate
- To reduce the level of a signal or frequency band (turn down or lower).
- Automation
- Recorded or drawn parameter changes (volume, pan, effect settings) that play back in sync with the project timeline.
- Band‑pass / High‑pass / Low‑pass / Notch
- Filters that allow or remove ranges of frequency: band‑pass allows a band, high‑pass removes lows, low‑pass removes highs, and notch removes a narrow target.
- Brickwall limiter
- A limiter that prevents output from exceeding a ceiling; commonly used in mastering to prevent overs but should be applied conservatively.
- Caterpillar / Log
- Descriptive terms for an over‑limited waveform that visually resembles a continuous flattened bar (sign of heavy limiting).
- Comb filtering
- Frequency cancellations caused by delayed or phase‑shifted versions of the same signal summing together; common with multi‑mic setups or reflections.
- De‑click / De‑noise / De‑essing
- Restoration tools: de‑click removes transient pops, de‑noise reduces broadband noise, de‑essing targets sibilant consonants in vocals.
- Depth / Width / Imaging
- Perceptual placement in front‑to‑back (depth) and left‑to‑right (width) stereo field; imaging is the ability to distinguish spatial placement precisely.
- Dim
- Momentary attenuation (often via monitor controller) used to check mixes at lower perceived levels.
- Flip the phase / reverse polarity
- Inverting the polarity of a signal 180°, used to correct phase cancellations.
- Hard / Soft clip
- Hard clip sharply truncates waveform peaks; soft clip rounds and introduces gentler harmonics.
- Harmonics / Harmonic distortion
- Overtones created by nonlinear processing or analog emulation that enrich tone (may be desirable in moderation).
- Jitter
- Timing errors in digital clocking that cause distortion or image instability, primarily an AD/DA concern.
- Kill
- A quick mute of a channel or frequency band (live sound / DJ parlance).
- MIDI / Sequencer
- MIDI is event-based musical control data; sequencers arrange and play back MIDI or audio clips.
- Mouth noise / Plosives / Sibilance
- Unwanted vocal artifacts: mouth noises (lip smacks), plosives (explosive P/B low bursts), and sibilance (harsh S/T high-energy spikes).
- Multitracks / Stems / Trackouts
- Multitracks are raw individual tracks; stems are grouped submixes; trackouts are an artist/producer’s exported session parts for remixing or mastering.
- Null test / Phase‑align
- Null test checks for differences by polarity inversions; phase‑align and time‑align techniques correct cancellations in multi‑mic or layered signals.
- Normalization
- Adjusting a file’s global gain to meet a peak or average target (does not alter dynamic shape beyond level).
- Parallel processing
- Mixing processed and unprocessed versions of a signal (e.g., parallel compression) to retain transients while adding weight.
- Phasing
- Combining similar signals with timing or polarity differences that cause comb filtering or movement in the stereo image.
- Preset
- A saved parameter set for a plugin or processor intended for reuse as a starting point.
- Resonant peaks / Ring
- Localized frequency peaks that ring or sustain; typically attenuated with narrow EQ or addressed in recording/mic placement.
- Sample augment / replace
- Layering (augment) or replacing (replace) audio events with samples to improve consistency or tone of drum hits and other percussive sources.
- Saturation curve
- Characteristic harmonic growth behavior of a saturation device (soft vs. aggressive) that affects tone and perceived loudness.
- Shelf (EQ)
- An EQ type that applies a gradual boost or cut above or below a selected frequency band.
- Sidechain / Sidechain input
- Using an external signal to trigger a processor (often a compressor) so it responds to that program material (eg. ducking bass with a kick).
- Smash / Smash‑style processing
- A deliberate heavy compression/limiting approach used for aggressive, loud commercial sounds (use cautiously).
- Smearing
- Lack of clarity in stereo imaging or transients often caused by excessive reverb, delay, or overprocessing.
- Soft clip
- See Soft clip (see above) — gentle saturation introduced close to threshold to preserve harmonics.
- Spectrum analyzer / Waveform
- Visual tools: spectrum analyzers show frequency content; waveforms show time‑domain amplitude — both are helpful diagnostic tools in mixing/mastering.
- Transients
- Initial short bursts in sound that give attack and definition; shaping transients controls perceived punch and clarity.
- Unity gain
- An input‑output gain state where signal level is unchanged (useful when testing chain behavior).
- Volume / Level / Loudness
- Level is the measurable electrical/audio magnitude; loudness is the perceptual sensation influenced by frequency and duration.
- Width
- Perceptual left‑to‑right dispersion of the stereo image; used creatively to place instruments and create spaciousness.
Common parameters across compressors, gates, EQs, delays, and reverbs — important when tuning for clinical use
- ADSR
- Attack, Decay, Sustain, Release — envelope controls that shape amplitude over time.
- Compressor: threshold, ratio, attack, release, knee, makeup gain
- Threshold defines trigger level; ratio sets reduction strength; attack/release control timing; knee smooths onset; makeup restores level.
- Limiter / Brickwall
- Ceiling protection at mastering stage; avoid excessive limiting for therapeutic music to preserve dynamics.
- Noise gate
- Removes low‑level noise below a set threshold — useful for silence between phrases but can produce artifacts if too aggressive.
- Delay / Reverb: pre‑delay, decay, diffusion, damping, dry/wet
- Controls for spatial effect behaviour — choose conservative, short‑settling room sounds for bedside music to avoid masking vocals.
Mastering, delivery, and clinical guidance
- Types of mastering
- Standard stereo mastering (final stereo file), stem mastering (grouped elements) and format‑specific masters (vinyl vs streaming).
- Metering: Peak, RMS, LUFS
- Peaks measure instantaneous amplitude; RMS is average energy; LUFS measures perceived loudness and is important for streaming normalization (typical target ≈ −14 LUFS for many platforms).
- Dynamic Range / Signal‑to‑Noise ratio (SNR)
- Dynamic range is the difference between quiet and loud passages; SNR measures signal versus background noise — both critical for clinical intelligibility on varied devices.
- Dithering
- Adds low-level noise when reducing bit depth to avoid quantization artifacts and preserve perceived detail.
- Metadata (ID3, ISRC)
- Embedding metadata ensures correct attribution, distribution tracking, and clinical cataloging; include clear licensing and intended use notes when donating tracks.
- Listening safety
- For clinical use prefer moderate listening levels, avoid fatiguing loudness, and provide stems/preview masters to enable local tailoring by clinicians.
Clinical & hearing terms
- Audiogram
- A clinical chart that plots hearing sensitivity by frequency; useful when adapting music for patients with hearing loss.
- Cochlea / Ear anatomy
- Basic hearing anatomy: outer ear → middle ear (ossicles) → inner ear (cochlea) — pathologies at different levels affect frequency perception and intelligibility.
- Masking (clinical)
- External or competing sounds that obscure therapeutic material; consider quieter clinical environments, headphone mixes, or EQ to avoid masking patient‑important elements.
Neuro-acoustic & neurodivergent terms
- Stochastic Resonance
- A phenomenon where adding moderate noise to a system enhances the detection of weak signals. In ADHD contexts, external auditory noise may help weak dopaminergic signals cross neural thresholds, improving attention and cognitive performance.
- Moderate Brain Arousal (MBA) Model
- A theoretical framework suggesting that ADHD brains are understimulated at baseline. External noise (pink, brown, white) can raise arousal to optimal levels for attention, explaining why some individuals with ADHD focus better with background sound.
- Predictive Coding Theory
- A neuroscience model proposing the brain constantly generates predictions about incoming sensory data. In ASD, prediction errors may be weighted differently, causing unpredictable stimuli to be more distressing — explaining the preference for highly structured, predictable music.
- Hyperacusis
- Heightened sensitivity to everyday sounds, common in ASD populations. Music for hyperacusis-sensitive listeners should avoid sudden transients, high-frequency harshness, and unpredictable dynamic changes; consider low-pass filtering around 4-5 kHz.
- Sensory Gating
- The brain's ability to filter irrelevant sensory information. Reduced sensory gating in ADHD and ASD can make filtering background noise difficult, affecting how therapeutic music should be designed for these populations.
- White Noise
- Broadband noise with equal energy across all frequencies (flat spectrum). Can sound harsh due to high-frequency content; useful for masking but may be fatiguing for extended listening. Better suited for short focus bursts than long study sessions.
- Pink Noise
- Noise with equal energy per octave, resulting in reduced high frequencies compared to white noise (−3 dB/octave roll-off). More comfortable for extended listening; often preferred for ADHD focus applications and sleep environments.
- Brown Noise (Brownian/Red Noise)
- Low-frequency-emphasized noise with steep high-frequency roll-off (−6 dB/octave). Resembles rumbling or distant thunder; particularly soothing for sensory-sensitive individuals and useful as a calming foundation layer in ASD-focused music.
- Brainwave Entrainment
- The phenomenon where neural oscillations synchronize to external rhythmic stimuli. Used therapeutically with isochronic tones or binaural beats to influence brain states: beta (14-30 Hz) for alertness, alpha (8-12 Hz) for relaxation, theta (4-8 Hz) for meditation.
- Binaural Beats
- An auditory illusion created when two slightly different frequencies are presented to each ear separately (requires headphones). The brain perceives a third "beat" at the difference frequency, potentially influencing brainwave states.
- Isochronic Tones
- Regular, evenly-spaced pulses of sound that create rhythmic amplitude modulation. Unlike binaural beats, isochronic tones work through speakers and may produce cleaner entrainment. Beta-range (14-18 Hz) pulses may support ADHD focus.
- Neurologic Music Therapy (NMT)
- An evidence-based treatment system using music to address neurological conditions including stroke, Parkinson's, traumatic brain injury, and developmental disorders. NMT techniques include Rhythmic Auditory Stimulation and Musical Attention Training.
- Rhythmic Auditory Stimulation (RAS)
- An NMT technique using rhythm to entrain and improve movement patterns, particularly gait rehabilitation. Requires metronomically stable tempo and clear rhythmic markers; tempo can be gradually adjusted to improve walking speed and symmetry.
- Lo-Fi / Chillhop
- Music genres characterized by relaxed tempos (70-90 BPM), warm analog textures, subtle vinyl crackle, and jazzy chord progressions. Popular for study/focus contexts; the moderate complexity and steady rhythm may support ADHD concentration without overstimulation.
- Transient (in ASD context)
- Sudden, sharp sound onsets (attacks) that can trigger startle responses in sensory-sensitive individuals. For ASD-friendly music, minimize high-transient instruments like bells, staccato strings, or sharp percussion attacks.
Clipping (hard / soft)
When a signal exceeds the maximum level and the waveform is flattened. Hard clipping produces harsh distortion; soft clipping introduces gentler harmonics that can sometimes be used musically but risk damaging quality if overdone.
Bit depth
Determines the resolution of each audio sample and therefore the dynamic range and noise floor (e.g., 16‑bit vs 24‑bit). Higher bit depth reduces quantization noise and is preferred during recording and mixing.
Sample rate
How many times per second an audio waveform is sampled (Hz/kHz). Common values: 44.1 kHz (CD), 48 kHz (video), 96 kHz (high‑resolution). Higher rates capture higher frequencies but increase file size.
Dithering
A small, controlled noise added when reducing bit depth (e.g., 24→16 bit) to prevent quantization distortion and preserve perceived audio quality in quieter passages.
File formats (WAV / FLAC / MP3)
WAV/AIFF: lossless, uncompressed masters for delivery. FLAC: lossless but smaller, good for downloads. MP3/AAC: compressed lossy formats for streaming and distribution where file size matters.
Stems & multitracks
Stems are grouped submixes (e.g., drums, vocals), while multitracks are all individual recorded tracks. Providing stems is useful for stem‑mastering and clinical or remix needs.
Bus / Submix
A routing path where multiple tracks are combined (e.g., drum bus). Processing (EQ/compression) on a bus affects all routed tracks and is a powerful way to achieve coherent tone and dynamics.
Equalization (EQ)
Shaping tonal balance by boosting/cutting frequency bands. Types include parametric (select frequency, Q), shelving (boost/cut above/below a frequency), and notch (very narrow cut for problem frequencies).
Filter types (HP / LP / BP / Notch)
High‑pass (HP) removes low frequencies; low‑pass (LP) removes high frequencies; band‑pass (BP) allows a band through; notch removes a narrow band. Useful for cleaning rumble, removing hiss, or hunting resonances.
Q / bandwidth
Controls the width of an EQ band; higher Q is narrower and surgical, lower Q is wider and gentler. Use Q to leave space for other elements while reducing masking.
Transient
A brief, high‑energy onset of a sound (attack of a drum or pluck). Transients are important for perceived clarity and punch — preserve or shape them intentionally using transient shapers or compressors.
Compressor parameters: threshold, ratio, attack, release, knee, makeup gain
Threshold sets when compression starts; ratio sets how much reduction; attack/release control timing; knee softens the onset; makeup gain restores level after gain reduction. Thoughtful settings keep dynamics expressive while controlling peaks.
Limiter / brickwall limiter
A limiter prevents the output from exceeding a ceiling; brickwall limiters act as an absolute ceiling to prevent intersample overs. Use sparingly to preserve dynamics and listening comfort.
Sidechain
A routing technique where one signal (e.g., kick) controls processing on another track (e.g., compressing bass when kick hits) to make space and avoid masking.
Metering: peak, RMS, LUFS
Peak measures instantaneous highest samples; RMS measures average energy; LUFS measures perceived loudness over time and is used for streaming normalization. Master to platform targets (commonly −14 LUFS for many services).
Normalization
Process that adjusts the overall level to meet a target peak or average — does not change dynamics or transient behavior beyond gain change.
Stereo field / panning / width
Placement of sounds left or right and the immersive width of the mix. Panning and width tools help separate elements and create a sense of space while maintaining focus for clinical listening (clear center for vocals).
Phase & time alignment
When two similar signals are out of phase they can cancel (comb filtering). Time‑aligning and phase correction keep multi‑mic setups and layered tracks coherent and full.
Reverb simulates room reflections; delay repeats a sound over time. Dry/wet controls the mix between unprocessed and processed signal. For therapeutic music, prefer warm, gentle reverb and modest decay to avoid drowning important vocal material.
Soft saturation adds pleasant harmonics (warmth) and perceived loudness; excessive distortion destroys clarity and should be avoided for healing playlists where comfort and intelligibility are priorities.
A processor that mutes signals below a set threshold — useful to clean room noise between phrases but can sound unnatural if thresholds are set too aggressively.
A professionally mixed/mastered track used as a target for tonal balance, width, and loudness during mixing and mastering. Use genre‑appropriate references to keep expectations realistic.
Reflections and room modes color recordings. Treatment or careful mic placement reduces resonant peaks that can make a mix sound muddy or boomy — especially important when music will be used in clinical environments with variable playback systems.
Dynamic range is the difference between quiet and loud passages; signal‑to‑noise ratio compares desired audio to background noise. For therapeutic tracks keep useful dynamic range while ensuring important details remain audible on quiet hospital devices.
Metadata: ID3 & ISRC
Embedded metadata (artist, title, track number, ISRC codes) helps distribution, identification, and clinical cataloging. Include clear licensing and intended‑use notes when donating tracks for clinical use.
For clinical or bedside playback prefer moderate volumes and limited durations. Avoid fatiguing levels and highly compressed masters — provide softer preview masters and stems if clinicians need customization.
Waveform (visual)
Diagram: simple generated waveform image (in‑repo sample).
