Reference

Glossary

Key terms used throughout this book, with page references to their principal discussions.

A
AAF (Advanced Authoring Format): A file interchange format for exchanging session data (audio, fades, automation, track layout) between Pro Tools and video editing software such as Premiere Pro, DaVinci Resolve, and Media Composer. Preferred over the older OMF format.
Absorption: The reduction of sound energy when sound waves strike a surface. Absorptive materials convert sound energy into heat, reducing reflections and reverberation.
Accent Micing: A microphone placement technique using a microphone placed close to a specific instrument within a larger ensemble to add clarity or presence to that instrument in the mix.
Acoustic Treatment: Materials and construction techniques used to control the sound characteristics of a room, including absorption panels, diffusers, and bass traps.
ADAT (Alesis Digital Audio Tape): A digital audio format and optical cable interface (ADAT Lightpipe) that carries up to eight channels of digital audio at 44.1 or 48 kHz over a single fiber optic cable.
ADC (Analog-to-Digital Converter): A device that converts continuous analog audio signals into discrete digital data (samples) for processing, recording, and storage in a DAW.
Additive Synthesis: A method of sound synthesis that builds complex tones by combining multiple sine wave harmonics at various frequencies and amplitudes.
ADM (Audio Definition Model): A metadata standard describing the bed-and-object layout of an immersive-audio master, carried in a Broadcast Wave file (ADM BWF) for Dolby Atmos and other object-based delivery.
ADR (Automated Dialogue Replacement): The process of re-recording dialogue in a studio after filming to obtain cleaner, more intelligible vocal tracks that sync with the original lip movements on screen.
ADSR Envelope: Attack, Decay, Sustain, Release: The four stages that shape how a synthesizer's amplitude, filter, or pitch changes over time from the moment a key is pressed to the moment it is released.
AES/EBU: A professional digital audio interface standard using XLR connectors, capable of carrying two channels of uncompressed digital audio. Named after the Audio Engineering Society and European Broadcasting Union.
AES67: An open interoperability standard for Audio over IP, allowing different AoIP protocols (Dante, Ravenna, Livewire) to communicate with each other.
Aliasing: A digital audio artifact that occurs when frequencies above the Nyquist limit fold back into the audible spectrum as false frequencies. Prevented by anti-aliasing filters in AD converters.
Ambient Micing: A microphone placement technique using microphones placed far from the source to capture the natural reverberance and spatial characteristics of a room.
Amplitude: The magnitude or strength of a sound wave, measured as the maximum displacement from the rest position. Perceived as loudness.
Analog Summing: The process of combining multiple audio signals using analog circuitry rather than digital math, often valued for its harmonic character and perceived warmth.
ARA2 (Audio Random Access): A plugin integration protocol that allows audio editors like iZotope RX to work directly on audio within the DAW timeline without rendering, enabling non-destructive spectral editing.
Atmos: See Dolby Atmos.
ATSC A/85: The Advanced Television Systems Committee standard for loudness in broadcast television in the United States, requiring dialogue to average approximately −24 LKFS. Enforced by the CALM Act.
Attack: The time it takes for a compressor or gate to begin acting once the signal crosses the threshold. Also the first stage of an ADSR envelope.
Automation: The ability to record and play back changes to mix parameters (volume, pan, mute, plugin settings) over time in a DAW.
Auxiliary (AUX) Send: A routing path that sends a copy of a track's signal to an auxiliary bus for parallel processing such as reverb or delay, without interrupting the main signal path.
B
Balanced Cable: An audio cable with three conductors (hot, cold, ground) that uses phase cancellation to reject noise and interference. Common balanced connectors include XLR and TRS.
Bass Trap: An acoustic treatment device designed to absorb low-frequency sound energy, typically placed in room corners to reduce standing waves and modal ringing.
Beat Detective: A Pro Tools feature that analyzes rhythmic audio, detects transients, and can conform audio to a tempo grid or extract tempo information from a performance.
Bit Depth: The number of bits used to represent each audio sample. Higher bit depth provides greater dynamic range and lower noise floor (e.g., 16-bit = 96 dB, 24-bit = 144 dB).
Blumlein Pair: A stereo microphone technique using two bidirectional (figure-8) microphones positioned coincidently at 90° to each other, producing a natural stereo image with excellent spatial accuracy.
Bounce to Disk: The process of rendering a Pro Tools mix (or selection) to a new audio file, combining all tracks, processing, and automation into a single stereo or multichannel file.
Broadcast Wave Format (BWF): An extension of the WAV format that includes metadata such as timecode position, used extensively in broadcast and post-production workflows.
Bus: A virtual audio pathway in a DAW used to route signals between tracks, sends, and outputs. Buses enable submixing, parallel processing, and complex signal routing.
C
Cadence: A chord movement that creates a sense of resolution or pause, punctuating the end of a musical phrase (for example, V–I).
CALM Act: The Commercial Advertisement Loudness Mitigation Act (2010), U.S. legislation requiring that commercial audio levels not exceed the average loudness of the program they accompany, enforcing ATSC A/85.
Cardioid: A heart-shaped polar pattern that picks up primarily from the front, partially from the sides, and rejects sound from the rear. The most common microphone pattern.
Channel Strip: The vertical section of a mixing console containing all the controls for a single input channel, typically including preamp gain, EQ, dynamics, auxiliary sends, pan, and fader.
Chord Progression: A succession of chords forming a song's harmonic backbone, usually described with Roman numerals relative to the key.
Chorus (Effect): A short-delay modulation effect (15–35 ms delay time with slight pitch detuning) that makes a single source sound like multiple voices or instruments playing together, adding width and thickness while keeping the sound upfront rather than pushed back in the mix. Distinct from reverb: chorus widens and fattens; reverb adds space and depth.
Circle of Fifths: A diagram arranging the twelve keys by ascending perfect fifths, showing key signatures and how closely related keys sit.
Click Track: A metronome track in a DAW that provides a steady tempo reference for musicians during recording or for syncing music to picture in film scoring.
Clip Effects: A Pro Tools feature that applies processing (such as EQ or gain) directly to individual audio clips before they reach the insert chain, enabling clip-level adjustments.
Clip Gain: A Pro Tools feature that adjusts the level of an individual audio clip before it reaches the channel's insert chain, essential for gain staging.
Close Micing: A microphone placement technique where the microphone is positioned within a few inches of the sound source to capture a direct, present signal with minimal room ambience.
Codec: Short for coder-decoder. A method of encoding and decoding digital audio or video. Examples include DNxHD, ProRes, H.264, AAC, and MP3.
Comb Filtering: A series of equally spaced peaks and notches in the frequency response caused by the interference of two copies of the same signal arriving at slightly different times. Produced by multi-microphone setups, room reflections off parallel surfaces, and monitor misalignment. Creates a hollow, filtered tone that EQ cannot correct; the solution is always physical—move the microphones or treat the room.
Comping: The editing process of assembling a final performance by selecting the best phrases, notes, or sections from multiple recorded takes into a single composite track. Most commonly applied to lead vocals and guitar solos. Pro Tools supports comping via playlist recording (multiple takes stored as separate playlists) and multitrack comping (takes on parallel tracks, muted except the chosen lines). The goal is to build the emotionally strongest performance, not the most technically perfect one.
Compression: A dynamics process that reduces the dynamic range of an audio signal by attenuating levels that exceed a set threshold, controlled by ratio, attack, release, and knee parameters.
Condenser Microphone: A microphone type that uses a thin diaphragm suspended near a fixed backplate to form a capacitor. Requires phantom power (typically 48V) and is known for detailed, accurate sound reproduction.
Count-off: A metronome count before recording begins in Pro Tools, giving the performer a tempo reference before the first beat. Configured in the Transport window.
Critical Band: A frequency range within which the cochlea processes sound as one unit; tones inside the same band mask and compete.
Crossfade: A transition between two audio clips where one fades out while the other simultaneously fades in, creating a smooth, seamless edit.
D
DAC (Digital-to-Analog Converter): A device that converts digital audio data back into a continuous analog signal for playback through speakers or headphones.
Dante: Digital Audio Network Through Ethernet. The dominant Audio over IP protocol, transmitting hundreds of channels of uncompressed audio over standard Ethernet with sub-millisecond latency. Developed by Audinate.
DAW (Digital Audio Workstation): Software used for recording, editing, mixing, and mastering audio. Examples include Pro Tools, Logic Pro, Ableton Live, and Studio One.
dB (Decibel): A logarithmic unit used to express the ratio of two values, commonly used to measure sound pressure level (SPL), signal level, and gain. An increase of approximately 10 dB is perceived as a doubling of loudness.
dBFS (Decibels relative to Full Scale): A unit of measurement for digital audio levels where 0 dBFS represents the maximum possible level before clipping.
dBTP (Decibels True Peak): A measurement of peak audio level that accounts for inter-sample peaks in the reconstructed analog waveform, not just the digital sample values. Critical for digital delivery.
dBu / dBV: Two related units for measuring the voltage of analog audio signals. dBu references 0.775 V RMS (the voltage across a 600 Ω load at 1 mW—the historic telephone-industry standard). dBV references 1 V RMS regardless of impedance. Professional equipment typically operates at +4 dBu nominal level; consumer equipment at −10 dBV. Neither scale is used for digital audio, where dBFS applies.
De-esser: A dynamics processor designed to reduce excessive sibilance (harsh ‘s' and ‘sh' sounds) in vocal recordings by compressing a narrow frequency band (typically 4–10 kHz).
Delay: A time-based audio effect that records an input signal and plays it back after a set period of time, creating echoes and rhythmic repetitions.
Dialogue Editing: The process of cleaning, smoothing, and assembling recorded dialogue for film or television, including noise reduction, room tone fills, and ensuring intelligibility.
Diatonic: Belonging to the seven notes of a given major or minor scale; diatonic chords and melodies use only those notes, with no accidentals.
DI Box (Direct Injection): A device that connects a high-impedance, unbalanced instrument output (electric guitar, bass, keyboards) to a low-impedance, balanced microphone-level input, performing level matching, impedance bridging, and signal balancing to minimize noise, distortion, and ground loops. Passive DI boxes use a transformer; active DI boxes use electronic circuitry powered by phantom power or a battery. Also used for reamping—sending a recorded DI signal back through an amplifier.
Diffusion: The scattering of sound waves in multiple directions when they strike an irregular surface, helping to create a more even and natural-sounding acoustic space.
Digital Summing: The process of combining multiple audio signals using mathematical calculations in a DAW, operating at 32-bit or 64-bit floating-point resolution.
Distant Micing: A microphone placement technique where the microphone is positioned 3 feet or more from the source to capture more room ambience and a blended sound.
Dither: A small amount of random noise intentionally added during bit-depth reduction (e.g., 24-bit to 16-bit) to smooth quantization errors and preserve low-level detail.
DNxHD / DNxHR: Avid's professional intraframe video codecs optimized for editing. DNxHD handles HD resolutions; DNxHR extends support to 4K and beyond. Recommended for video in Pro Tools.
Dolby Atmos: An object-based immersive audio format that places sound in three-dimensional space, including height channels. Pro Tools Studio and Ultimate include an integrated Dolby Atmos renderer.
Drop Frame: A SMPTE timecode format (29.97 fps) that periodically skips frame numbers to keep the timecode count synchronized with real clock time for NTSC video.
Dynamic Microphone: A microphone type that generates an electrical signal through electromagnetic induction, using either a moving coil attached to a diaphragm or a ribbon element. Durable, no phantom power required.
Dynamic Range: The difference between the quietest and loudest levels a system can reproduce, measured in dB.
E
EBU R128: The European Broadcasting Union loudness recommendation targeting −23 LUFS for broadcast content, ensuring consistent loudness across programs.
Eclipsa Audio: A royalty-free, open-source 3D audio format developed by Samsung and Google, built on the IAMF specification. Designed as a free alternative to Dolby Atmos for spatial audio delivery.
Elastic Audio: A Pro Tools feature that allows real-time time-stretching and pitch-shifting of audio clips, useful for tempo conforming, fixing timing, and creative manipulation.
Equal Loudness Contours: See Fletcher-Munson curves.
Equalization (EQ): The process of adjusting the balance of frequency components in an audio signal using filters to boost or cut specific frequency ranges.
Expander: A dynamics processor that reduces the level of signals below a threshold, increasing dynamic range. Works opposite to a compressor; a noise gate is an extreme expander.
F
Fader: A sliding control on a mixing console or DAW mixer used to adjust the volume level of a channel or bus.
Feedback: In audio, the loop created when an output signal is fed back into an input, causing howling or oscillation. In delay/reverb, the control that determines how many times the signal repeats.
Field Recording: The practice of recording audio outside a studio environment using portable equipment such as Sound Devices MixPre or Zoom F-series recorders.
Film Scoring: The composition and production of original music written to accompany visual media, timed to sync with specific scenes to enhance dramatic and emotional impact.
Filter: A processor that removes or attenuates frequencies above (low-pass), below (high-pass), or around (notch/band-pass) a specified frequency.
Flanger: A time-based effect created by mixing two identical signals with a continuously varying short delay (typically 1–15 ms), producing a sweeping, jet-like sound through comb filtering.
Fletcher-Munson Curves: Equal loudness contour curves demonstrating that human hearing perceives different frequencies at different apparent loudness levels, particularly at low listening volumes where bass and treble appear quieter.
Flutter Echo: A rapid series of echoes caused by sound reflecting repeatedly between two parallel surfaces, creating a distinctive ringing or buzzing quality.
FM Synthesis: Frequency Modulation synthesis, where one oscillator (modulator) modulates the frequency of another (carrier) to produce complex, often metallic or bell-like timbres.
FMOD: A middleware audio engine by Firelight Technologies used for implementing interactive audio in video games.
FOH (Front of House): In live sound, the mixing position located in the audience area where the FOH engineer controls what the audience hears through the PA system.
Folder Track: A Pro Tools organizational feature that groups related tracks together visually and can sum their audio, helping manage large sessions.
Foley: The art of creating and recording sound effects in sync with visual media, such as footsteps, clothing rustle, and object interactions, performed in a studio while watching the picture.
Frequency: The number of complete vibration cycles per second of a sound wave, measured in Hertz (Hz). Perceived as pitch.
Frequency Response: The range of frequencies a device (microphone, speaker, amplifier) can reproduce and the relative level at which each frequency is output.
G
Gain: The amount of amplification applied to a signal, measured in dB.
Gain Staging: The practice of setting optimal signal levels at each point in the audio chain to maximize signal-to-noise ratio while avoiding clipping and distortion.
General MIDI (GM): A standardized specification that defines a set of 128 instrument sounds mapped to specific program numbers, ensuring consistent playback across different MIDI devices.
Graphic EQ: An equalizer with fixed frequency bands, each controlled by its own slider, providing a visual representation of the frequency curve. Common configurations include 31-band.
Grid Mode: A Pro Tools edit mode that snaps clip boundaries and edits to the nearest grid line based on the selected time division.
H
H.264 / H.265: Interframe video compression codecs that achieve small file sizes by encoding differences between frames. More CPU-intensive than intraframe codecs; may cause sync issues in DAWs.
Haas Effect: A psychoacoustic phenomenon in which a short delay (1–30 ms, typically 15–25 ms) panned opposite to the dry signal is perceived by the brain as a single sound coming from the direction of the earlier arrival, while adding width and size. Named after Helmut Haas. Used in mixing to widen mono sources without reverb, by duplicating a signal, delaying the copy by 15–25 ms, and panning the two copies apart. Check in mono when using this technique—phase cancellation is a real risk.
Harmonic: A frequency component of a complex sound that is an integer multiple of the fundamental frequency.
Headroom: The margin between the nominal operating level and the maximum level before clipping. In mixing, leaving headroom (peaks at −3 to −6 dBFS) gives the mastering engineer room to work.
HEAT (Harmonically Enhanced Algorithm Technology): A Pro Tools feature that adds subtle analog-style harmonic saturation to each channel, emulating the warmth of analog console circuitry.
Hertz (Hz): The unit of measurement for frequency, equal to one cycle per second. Audio frequency range spans approximately 20 Hz to 20 kHz.
High-Pass Filter (HPF): A filter that allows frequencies above a specified cutoff frequency to pass while attenuating frequencies below it. Used to remove rumble, handling noise, and low-frequency buildup.
Hit Point: A specific moment in a video or film where a sound event must occur precisely (e.g., a gunshot, door slam, music cue entrance), marked using Memory Locations in Pro Tools.
I
IAMF: Immersive Audio Model and Formats. The technical specification underlying Eclipsa Audio, developed by the Alliance for Open Media.
Impedance: The total opposition to the flow of alternating current in a circuit, measured in ohms. Microphones are typically low impedance (150–600Ω); line-level equipment is higher.
Input Monitoring: A DAW feature that routes the live input signal directly to the monitors so the performer can hear themselves in real time during recording.
Insert: A point in the signal chain where a processor is placed directly in-line with the audio signal, processing 100% of the signal. Contrasted with sends, which create parallel copies.
Interframe Compression: A video compression method (H.264, H.265) that encodes only the differences between consecutive frames, achieving smaller file sizes but requiring more CPU for decoding.
Interval: The distance in pitch between two notes, named by the scale steps it spans and its quality (major, minor, perfect).
Intraframe Compression: A video compression method (DNxHD, ProRes) that encodes each frame independently, enabling smooth scrubbing and reliable sync in editing applications.
Inverse Square Law: In acoustics, the principle that sound intensity decreases proportionally to the square of the distance from the source. Doubling the distance reduces the level by approximately 6 dB.
ISRC (International Standard Recording Code): A twelve-character alphanumeric code (ISO 3901:2019) that permanently and uniquely identifies a specific sound recording—not the underlying composition, but the specific master. Used by streaming platforms, SoundExchange, and sync databases to credit streams and route royalties. Assigned by your distributor at no charge, or registered directly at usisrc.org for a one-time $95 fee that covers up to 100,000 codes per year. Must be embedded in the delivered WAV or MP3 file before distribution.
iZotope Ozone: An industry-standard mastering suite offering a complete processing chain including EQ, dynamics, exciter, imager, maximizer, Stem EQ, and comprehensive LUFS metering.
iZotope RX: The industry-standard audio repair suite for post-production, featuring spectral editing, Dialogue Isolate, De-noise, De-reverb, De-click, De-clip, De-hum, Repair Assistant, and ARA2 integration.
K
Knee: A compressor parameter that determines how gradually or abruptly compression engages as the signal approaches the threshold. A soft knee applies compression gradually; a hard knee engages abruptly.
L
Large Diaphragm Condenser: A condenser microphone with a diaphragm typically 1 inch or larger, valued for its warm, full sound on vocals, acoustic instruments, and voiceover.
Latency: The delay between an audio input and its output, caused by digital processing and buffer settings. Low latency is essential for real-time monitoring during recording.
Leader / Follower: The synchronization relationship between devices where the leader generates the master clock or timecode and all follower devices lock to it.
Limiter: A compressor with a very high ratio (typically 10:1 or higher, often ∞:1) designed to prevent audio from exceeding a set ceiling. Used in mastering to maximize loudness while preventing clipping.
LKFS (Loudness K-weighted relative to Full Scale): A unit of loudness measurement equivalent to LUFS, used in the ATSC A/85 broadcast standard.
Loop Recording: A Pro Tools recording mode that repeatedly records over a selected range, storing each pass as a clip in the Clip List for easy comparison and selection of the best take.
Low-Pass Filter (LPF): A filter that allows frequencies below a specified cutoff frequency to pass while attenuating frequencies above it.
LUFS (Loudness Units relative to Full Scale): A standardized loudness measurement based on ITU-R BS.1770, accounting for how the human ear perceives loudness across frequencies. Used by streaming platforms: Spotify targets approximately −14 LUFS, Apple Music approximately −16 LUFS, YouTube approximately −14 LUFS.
M
M&E Mix (Music and Effects): A mix containing all music and sound effects but no dialogue, required for international film distribution to allow foreign language dubbing.
Mantissa and Exponent: The two parts of a floating-point number: the exponent scales the magnitude (roughly, how loud) while the mantissa carries the precision (the fine detail). Splitting the bits this way is what gives 32-bit float its enormous dynamic range.
Marker: See Memory Location.
Mastering: The final step in audio production where the stereo or surround mix is processed for consistency, tonal balance, loudness, and format preparation for distribution.
Memory Location: A saved position in a Pro Tools session (also called a marker) used to navigate to specific points, mark hit points, store zoom settings, or identify song sections.
Mid/Side (M/S) Processing: A technique that separates a stereo signal into a Mid channel (mono information identical in both speakers) and a Side channel (difference information), enabling independent processing of center vs. stereo content.
MIDI (Musical Instrument Digital Interface): A technical standard for communication between electronic musical instruments, computers, and related devices. Transmits performance data (note, velocity, CC) rather than audio.
MIDI 2.0: The 2020 update to the MIDI protocol, offering 16-bit velocity and 32-bit Control Change resolution, per-note controllers, bidirectional communication, and backward compatibility with MIDI 1.0.
MIDI Timecode (MTC): A protocol that translates SMPTE timecode into MIDI format, allowing MIDI devices to synchronize with video and other timecoded media.
Missing Fundamental: The pitch the brain reconstructs from a tone's harmonic series when the fundamental frequency itself is absent.
Mixing: The process of combining, balancing, and processing multiple recorded tracks into a cohesive stereo or multichannel output using volume, panning, EQ, dynamics, and effects.
Modal Ringing: A sustained resonance that occurs when a room's resonant frequency causes the room itself to vibrate sympathetically, creating audible coloration at specific frequencies.
Mode: A scale derived by starting on a different degree of the major scale (Dorian, Phrygian, Mixolydian), each with its own color.
Mono Compatibility: The quality of a stereo mix that allows it to sum to a single channel without significant loss of elements, level, or intelligibility. Tested by engaging a mono switch on the monitor controller or master fader metering plugin. Phase cancellation in hard-panned stereo effects (chorus doublers, wide reverbs, stereo FX) is the most common cause of mono collapse. XY coincident mic techniques offer superior mono compatibility compared to spaced pairs. A mix must pass the mono check before delivery.
Moving Coil Microphone: A type of dynamic microphone where a coil of wire attached to the diaphragm moves within a magnetic field to generate an electrical signal.
Multiband Compression: A dynamics process that splits the audio into separate frequency bands and applies independent compression to each, allowing targeted dynamic control without affecting other frequencies.
N
Noise Floor: The level of residual background noise in a recording system when no signal is present, determined by the quality of equipment and the bit depth of the digital system.
Noise Gate: A dynamics processor that silences an audio signal when it falls below a set threshold, used to eliminate noise, bleed, and unwanted sound during quiet passages.
Non-Drop Frame: A SMPTE timecode format (29.97 fps) that counts every frame sequentially without skipping. Easier for calculations but gradually drifts from real clock time.
Notch Filter: A narrow-band EQ filter that sharply attenuates a specific frequency, used to remove resonances, hum, or feedback at a precise point.
Nyquist Theorem: The principle stating that the sample rate must be at least twice the highest frequency to be captured. For the full audible range (20 kHz), a minimum sample rate of 40 kHz is required (CD standard: 44.1 kHz).
O
Object-Based Audio: An immersive audio approach where individual sounds are treated as objects with position metadata, allowing a renderer to adapt playback to any speaker configuration. Used by Dolby Atmos and Sony 360 Reality Audio.
Octave: The interval between a note and one at double or half its frequency; the two share the same letter name.
Off-Axis: Sound arriving at a microphone from any angle other than the primary pickup direction (on-axis). Off-axis response varies by polar pattern.
OMF (Open Media Framework): An older file interchange format for exchanging session data between DAWs and video editors. Largely replaced by AAF.
On-Axis: Sound arriving at a microphone directly from the front, along its primary pickup direction, where frequency response is most accurate.
ORTF: A stereo microphone technique using two cardioid microphones spaced 17 cm apart and angled at 110°, developed by the Office de Radiodiffusion-Télévision Française. Produces a natural, wide stereo image.
Oscillator: A circuit or algorithm in a synthesizer that generates a periodic waveform (sine, square, sawtooth, triangle) as the raw sound source.
Oversampling: Processing audio at a higher sample rate than the session rate to improve the accuracy of digital processing (especially limiting and saturation), then converting back. FabFilter Pro-L offers up to 32x oversampling.
P
Pan / Panning: The distribution of an audio signal between the left and right channels of a stereo field, creating the perception of spatial positioning.
Parallel Compression: A mixing technique where a heavily compressed copy of a signal is blended with the dry (uncompressed) signal, preserving transients and dynamics while adding sustain and body.
Parametric EQ: An equalizer offering continuous control over frequency, gain, and bandwidth (Q) for each band, allowing precise surgical or broad tonal adjustments.
Passaggio: In singing, the transition zone between vocal registers (chest voice and head voice) where the voice must change gears; a melody that sits right on a singer's passaggio is harder to perform cleanly, which is why it factors into choosing a song's key.
Patchbay: A panel of connectors that provides a central routing point for studio equipment. The top row typically carries outputs and the bottom row carries inputs in a normalized configuration.
Pentatonic Scale: A five-note scale (major or minor) that omits the most dissonant steps, widely used in rock, blues, pop, and folk.
Phantom Power (+48V): A DC voltage supplied through a microphone cable (typically via XLR) to power condenser microphones and active DI boxes. Standard voltage is 48 volts.
Phase: The position of a point in a waveform's cycle at a given time, measured in degrees (0°–360°). When two identical signals are in phase they reinforce; out of phase they cancel.
Phaser: A time-based effect that splits a signal, shifts the phase of one copy through a series of all-pass filters, and recombines it with the original, creating a sweeping, spatial sound.
Pitch Correction: The use of software to adjust the intonation of a recorded performance, ranging from transparent tuning (invisible repair of slightly flat or sharp notes) to the hard-tuned robotic effect popularized by Cher's “Believe” (1998) and T-Pain. Primary tools: Melodyne (via ARA2 integration in Pro Tools—best for transparent, note-by-note correction) and Auto-Tune (real-time correction; Auto-Tune Pro for Graph Mode precision). Setting Retune Speed to zero produces the deliberate stepped effect.
Playlist: In Pro Tools, a collection of clips on a track that can be swapped for alternative takes. Playlist recording stores each pass as a separate playlist for easy comping.
Podcast: A series of spoken-word audio episodes distributed via RSS for on-demand listening. Podcast production involves recording, editing, and mastering voice-focused content, typically targeting −16 LUFS loudness.
Polar Pattern: A graph showing a microphone's sensitivity to sound arriving from different directions. Main types: cardioid, figure-8 (bidirectional), and omnidirectional.
Pre-delay: The time between the original (dry) sound and the onset of the first reverb reflections. Increasing pre-delay separates the dry signal from the reverb, improving clarity.
Pre-roll: A configurable amount of time that Pro Tools plays back before the punch-in point, giving the performer context before recording begins.
Print Master: The final mixed audio deliverable for a film or broadcast program, accompanying the finished picture for distribution.
PRO (Performing Rights Organization): An organization that licenses the public-performance right in a song and collects performance royalties for its songwriter and publisher members. The four U.S. PROs are ASCAP and BMI (open to all songwriters) and the invitation-only SESAC and GMR.
ProRes: Apple's family of intraframe video codecs (Proxy, LT, 422, HQ, 4444) widely used in post-production. Smooth playback and reliable sync in DAWs.
Proximity Effect: The increase in bass response that occurs when a directional microphone is placed very close to a sound source.
Punch In / Punch Out: A recording technique where recording is activated (punch in) and deactivated (punch out) at specific points, allowing re-recording of a section while preserving the rest of the take.
Q
Q (Quality Factor): A parameter of a parametric EQ that controls the bandwidth of the filter. A high Q value creates a narrow, surgical band; a low Q creates a wide, gentle curve.
Quantization: The process of aligning MIDI notes or audio transients to the nearest grid division, correcting timing inaccuracies in a performance.
R
Ratio: A compressor parameter expressed as X:1 that determines how much the signal above the threshold is reduced. At 4:1, a signal 4 dB above threshold is reduced to 1 dB above. At ∞:1, the compressor becomes a limiter.
Reference Track: A commercially released track used during mixing or mastering for A/B comparison to calibrate ears and ensure tonal balance, loudness, and frequency response are competitive.
Reflection: Sound that bounces off a surface and returns to the listener. Early reflections arrive within the first 5–100 ms; late reflections make up the reverb tail.
Release: The time it takes for a compressor or gate to stop acting once the signal drops below the threshold. Also the final stage of an ADSR envelope.
Reverb (Reverberation): The persistence of sound in a space after the direct sound has stopped, created by many overlapping reflections from room surfaces. Can be natural or simulated with processors.
Ribbon Microphone: A type of dynamic microphone that uses a thin metal ribbon suspended in a magnetic field. Known for a smooth, natural sound with gentle high-frequency rolloff. Typically bidirectional; fragile, avoid phantom power on vintage models.
RMS (Root Mean Square): A method of calculating average signal level over time, providing a more meaningful measure of perceived loudness than peak levels. Largely supplemented by LUFS in modern workflows.
Room Tone: The ambient background sound of a recording location (HVAC, outdoor atmosphere, room reflections). Recorded on set and used to fill gaps in dialogue editing for seamless, natural edits.
S
S/PDIF: Sony/Philips Digital Interface Format, a consumer/prosumer digital audio connection using coaxial (RCA) or optical (TOSLINK) cables, carrying two channels of digital audio.
Sample Library: A collection of pre-recorded audio samples organized by instrument, genre, or sound type, used in samplers and virtual instruments for music production.
Sample Rate: The number of times per second an analog audio signal is measured (sampled) during analog-to-digital conversion, measured in Hz. CD standard: 44,100 Hz (44.1 kHz); professional standard: 48 kHz or 96 kHz.
Sample Rate Conversion (SRC): The process of changing the sample rate of a digital audio file (e.g., 96 kHz to 44.1 kHz). High-quality SRC algorithms preserve audio fidelity; poor SRC introduces artifacts.
Sampler: A device or software instrument that plays back recorded audio samples, triggered by MIDI input. Samples can be looped, layered, and manipulated for realistic or creative playback.
Saturation: The introduction of harmonic distortion to an audio signal, emulating the warmth and character of analog tape or tube equipment. Common mastering tools include Soundtoys Decapitator and Waves Kramer Master Tape.
Send: A routing path that creates a copy of a track's signal at a specified level and routes it to a bus for parallel processing (e.g., reverb, delay), without interrupting the main signal.
Shelf EQ: An equalizer filter that boosts or cuts all frequencies above (high shelf) or below (low shelf) a specified frequency by a uniform amount.
Shuffle Mode: A Pro Tools edit mode where moving or trimming a clip automatically shifts adjacent clips to fill gaps or make room, maintaining the relative order of clips.
Side-chain Compression: A technique where the compressor's detection circuit is triggered by an external signal (the side-chain input) rather than the signal being compressed. Classic example: using a kick drum to trigger compression on a bass track.
Signal-to-Noise Ratio (SNR): The ratio between the desired signal level and the background noise level, measured in dB. Higher SNR indicates cleaner audio.
Slip Mode: A Pro Tools edit mode that allows clips to be moved freely without affecting other clips on the track.
Small Diaphragm Condenser: A condenser microphone with a diaphragm smaller than 1 inch, valued for its accurate transient response and extended high-frequency detail. Common for overheads, acoustic instruments, and stereo techniques.
SMPTE Timecode: A standard timecode developed by the Society of Motion Picture and Television Engineers that assigns a unique address (hours:minutes: seconds:frames) to each frame of audio/video for synchronization.
Sound Design: The process of creating, acquiring, manipulating, and generating audio elements for media including effects, ambience, Foley, and dialogue treatment.
Source-Connect: An industry-standard software tool for transmitting real-time, broadcast-quality audio between studios over the internet, commonly used for remote ADR, voiceover, and music overdub sessions.
Spaced Pair (A/B): A stereo microphone technique using two microphones spaced apart (typically 3–10 feet), creating stereo through time-of-arrival differences.
Spectral Editing: A technique for visualizing and manipulating audio in the frequency domain using a spectrogram display. Allows surgical removal of unwanted sounds. iZotope RX is the industry-standard spectral editor.
Spot Mode: A Pro Tools edit mode that prompts for an exact timecode location when placing or moving clips, essential for synchronizing audio to specific video frames in post-production.
Standing Wave: A resonance pattern that occurs when sound reflects between parallel surfaces at a wavelength related to the distance between them, creating areas of reinforcement and cancellation.
Stem: A bounced audio file representing one group of related tracks—all drums summed to one file, all guitars to another, lead vocal alone—giving the mix or mastering engineer a clean, plugin-free signal to process.
Stereo Imaging: Processing that adjusts the perceived width, depth, and spatial characteristics of a stereo mix. Can operate in frequency bands for independent control of bass vs. treble width.
Strip Silence: A Pro Tools feature that automatically removes or separates silent portions of audio clips based on configurable threshold, duration, and padding parameters.
Subtractive Synthesis: The most common synthesis method, starting with a harmonically rich waveform from an oscillator and using filters to remove (subtract) unwanted frequencies to shape the sound.
Surround Sound: A multichannel audio format using more than two speakers to create an immersive listening experience. Common formats include 5.1 (six speakers) and 7.1 (eight speakers).
T
Tempo: The speed of music, measured in beats per minute (BPM).
Tempo Map: A series of tempo changes programmed into a DAW session, used in film scoring to ensure music hits sync precisely with on-screen action at varying tempos.
Threshold: The signal level at which a dynamics processor (compressor, limiter, gate, expander) begins to act.
Time Signature: A notation such as 4/4 or 3/4 showing how many beats are in each measure and which note value gets the beat.
Time Stretching: The process of changing the duration of an audio signal without affecting its pitch, or vice versa. Implemented in Pro Tools through Elastic Audio.
Timecode: See SMPTE Timecode.
Transducer: A device that converts energy from one form to another. Microphones convert acoustic energy to electrical; speakers convert electrical to acoustic.
Transient: The brief, high-amplitude attack at the onset of a sound—the initial spike before the sustained body of the note. The click of a kick drum beater, the crack of a snare, the pluck of a guitar string. Transients carry most of the perceived punch and attack in a mix. Compressor attack and release settings determine how much of the transient passes through before the compressor engages; slower attack preserves the transient (more punch) while faster attack clamps it (more control).
Triad: A three-note chord built in stacked thirds (root, third, fifth); major and minor triads are harmony's building blocks.
TRS (Tip-Ring-Sleeve): A 1/4-inch audio connector with three contact points, used for balanced mono connections or unbalanced stereo connections (headphones, insert cables).
True Peak: The actual peak level of a reconstructed analog waveform, which can exceed the digital sample values due to inter-sample peaks. Mastering engineers use true-peak limiters set to −1.0 dBTP or lower.
TS (Tip-Sleeve): A 1/4-inch audio connector with two contact points, used for unbalanced mono connections such as guitar cables and some patch cables.
Tumbao: The syncopated, repeating bass (and conga) pattern that drives Afro-Cuban, salsa, and related Latin styles, locking to the clave.
U
Unbalanced Cable: An audio cable with two conductors (signal and ground), more susceptible to noise and interference than balanced cables. Common unbalanced connectors include TS and RCA.
V
VCA Fader (Voltage Controlled Amplifier): A Pro Tools feature that provides a master fader controlling the relative levels of grouped tracks without altering their individual routing, inserts, or sends.
Velocity: In MIDI, a value (0–127) representing how hard a note is played, typically controlling volume, timbre, or both in the receiving instrument.
VocAlign Ultra: An ARA2-integrated vocal alignment tool that automatically matches the timing of a replacement vocal to the original, widely used in ADR and vocal production.
Voice Leading: The craft of moving smoothly from one chord to the next by minimizing the motion of each individual note or voice.
W
Waveform: A visual representation of a sound wave showing amplitude over time.
Wavelength: The physical distance between two consecutive identical points on a wave (e.g., peak to peak), inversely proportional to frequency.
Wavetable Synthesis: A method of synthesis that stores short, single-cycle waveforms in a table and morphs between them to create evolving, complex timbres.
WNS (Waves Noise Suppressor): A Waves real-time noise reduction plugin with six adjustable frequency bands and a Suggest feature, designed for cleaning dialogue and broadcast audio.
Word Clock: A dedicated synchronization signal (transmitted over 75-ohm BNC cable) that ensures multiple digital audio devices sample at precisely the same rate, preventing clicks, pops, and distortion from sample slips.
Wwise: A middleware audio engine by Audiokinetic used for implementing interactive and adaptive audio in video games.
X
XLR: A professional audio connector with three pins (or more) providing a secure, balanced connection. Standard for microphones, AES/EBU digital audio, and professional equipment.
XY Technique: A coincident stereo microphone technique using two identical cardioid microphones positioned with capsules as close together as possible, angled 90°–110° apart, producing a mono-compatible stereo image.