Glossary

A

AES/EBU: Audio Engineering Society/European Broadcast Union. A professional transmission protocol that specifies two channels of data through an XLR cable as the standard for digital audio.

Audio region: A visual representation of a Pro Tools audio file. Regions can be whole audio files or segments of audio files and are usually displayed during editing as audio waveforms.

Audio signal flow: The path that audio takes through a mixer. In Pro Tools, this path is generally fixed, moving from top to bottom through audio track, auxiliary input, and master fader channel strips.

Audio track: In Pro Tools, a channel that holds and controls recorded or imported audio files.

AudioSuite plug-ins: Digidesign’s nonreal-time plug-ins. They process audio directly to disk, creating a new audio file that includes the effected signal.

Automation pass: In Pro Tools, automation recorded during the playback of a session.

Automation playlist: In Pro Tools, a visual representation of a track’s automation parameters (such as volume, mute, and pan). Pro Tools creates a separate automation playlist for each parameter that you write.

Auxiliary input: In Pro Tools, an input that lets you add mono or stereo effects to bussed signals. It’s also useful for submixes and other audio-routing tasks.

B

Balanced line: A cable with two conductors and a ground connection surrounded by a shield. Balanced lines are less prone to interference than unbalanced lines; thus, they help keep recordings free of noise.

Binaural auditory system: The two-ear auditory system that lets us locate sounds in space.

Bit depth: The number of bits used to describe each sample taken during recording. For example, if you’re recording at 24-bit resolution and a sample rate of 44.1 kHz, there will be 44,100 individual 24-bit representations of the sound recorded each second. Also known as bit resolution.

BNC/word clock: The coaxial cable (resembling video cable) that connects devices that run in sync.

Breakpoints: Breakpoints indicate changes in the value of an automation parameter. They’re displayed along a graphic curve, which you can grab and move when performing edits.

Bus: An audio bus carries audio signals from different tracks and delivers them to other destinations within a mixer. In Pro Tools, busses are used mainly to send audio signals from one or more audio tracks to a single auxiliary input, where a DSP effect is added.

C

Cardioid mic: A heart-shaped mic pick-up pattern that accepts sounds from the front (on-axis) and attenuates signals that are 180 degrees off-axis.

Channel: The physical inputs and outputs of the Pro Tools system.

Channel strip: Each track in a Pro Tools session is displayed in the Mix window as a channel strip. Channel strips let you control the mix functions of a track, such as level, mute, pan, and sends. The five types of channel strips are audio tracks, auxiliary inputs, instrument tracks, master faders, and MIDI tracks.

Click track: An absolute time reference that can help you produce takes with a steadier feel. It can also help you properly align tracks when you’re overdubbing, editing, and mixing.

Clipping: Digital distortion that occurs when you record a signal at levels that overload your system’s inputs. When a signal clips, it distorts, and the peaks of its waveform are literally clipped off.

Condenser mic: More sensitive, accurate, and expensive than dynamic mics, condenser mics are used frequently in recording studios.

Conductor ruler: In Pro Tools, a ruler that indicates important track locations within a session.

Controller: Any device that’s used to send MIDI without necessarily making a sound on its own.

Crossfade: An overlapping fade-out and fade-in placed between two adjoining audio regions. Crossfades let you smooth transitions between separate audio regions on a track.

D

Delay time: The length of time it takes for a sound to return to its source. The delay time tells you how big a space is.

Destructive editing: Editing functions in Pro Tools that permanently alter the parent audio file on disk.

Dither: A form of randomly generated noise that helps smooth out fade-ins or fade-outs from silence. Dither can also help smooth crossfades between low-level audio regions.

DSP: Digital signal processing. In Pro Tools, DSP refers to the manipulation or processing of digital audio. In Pro Tools LE systems, all DSP tasks are handled by the host computer’s CPU. The system’s total DSP power thus depends on the processing power of the host computer.

DSP plug-in: Software that lets you add effects such as reverb, compression, and EQ to audio signals within the Pro Tools environment.

Dynamic effects: Dynamic effects act upon an audio signal’s volume level. Examples of dynamic effects are compressors, limiters, expanders, and gates. Each of these effects alters the volume level of an audio signal above or below a specified volume threshold.

Dynamic mic: The least expensive type of mic. It can handle lots of volume and is durable enough to survive most live settings. It tends to accentuate mid-range and can sometimes make tracks sound boxy.

Dynamic range: The difference between the softest and the loudest volume produced by a sound source.

E

Edit playlist: In Pro Tools, a visual representation of a track’s current arrangement of regions. An edit playlist can contain a single region or multiple regions.

Edit selection: In Pro Tools, the actual audio region and/or track space that’s highlighted when you make a selection. Edit selections can include a single region or multiple regions and can include the space before, after, and in between regions.

Effects loop: An effects loop lets you add an effect to multiple tracks simultaneously. Also known as a send-and-return submix.

EQ: Equalization. The process of cutting or boosting the volume level of specific frequencies of an audio signal. EQ is used to open up frequency ranges and thus enhance the clarity, spaciousness, and blending of sounds in a mix.

F

Fade: A volume curve that controls the rate of increase (fade-in) or decrease (fade-out) of a region’s volume. Fades let you smooth the entrance and exit of audio during a mix. Fade-ins are placed at the start of regions; fade-outs are placed at the end.

Feedback loop: Created when an active microphone picks up its own signal from a loudspeaker and amplifies that signal again in a self-perpetuating cycle.

Figure-8 mic: A figure-8 mic picks up sound from both the front and back. Also known as a bidirectional mic.

G

Gain stage: Any point in an audio signal path where the audio signal is amplified (boosted) or attenuated (cut). The volume knob on your stereo, for instance, is a gain stage. Likewise, every amp, pre-amp, fader, and effect in your Pro Tools system is a gain stage.

Gain staging: The process of setting all gain stages in a system to their optimal values.

H

Handle value: In Pro Tools, a preserved segment of the original audio file before and after each region. It can be useful for fine-tuning the boundaries of a region.

I

Input selectors: Controls that let you assign audio input from external sources (via the Pro Tools interface) or from internal busses.

Inserts: Controls that let you add effects on channel strips. You can assign internal software effects and external hardware effects to inserts.

Interleaved stereo files: Single-file stereo files.

I/O: Input/output. The direction of an audio signal with respect to an audio device. Input is where audio signal enters the device; output is where audio signal leaves the device.

K

Keyboard workstation: A keyboard that includes an onboard synthesizer, sequencer, effects, and often, a sampler. Originally conceived as “one-stop shopping” for full audio production, keyboard workstations are more often used today as hot-rod controllers and for onstage performance.

L

Latency: The lag time between audio entering and leaving your recording system. Pro Tools LE systems are susceptible to latency because of the heavy processing load placed on the host computer’s CPU.

Line insert: In Pro Tools, a line insert applies its effect only to the track on which it’s inserted.

Line-level: A nominal preamplified signal between +4 dB (pro) and +10 dBV (consumer) that’s used to connect certain studio hardware devices such as keyboards, preamps, and mixers.

M

Main paths: In Pro Tools, logical groupings of inputs, outputs, inserts, or busses, such as a stereo (two-channel) output.

Master controller: A device, usually a keyboard or synthesizer, that’s used to play back all of the other MIDI equipment in the studio.

Master fader: In Pro Tools, a master fader controls the level of a session’s main outputs. Master fader inserts let you add effects post-fader to the main mix.

Mastering: The process of preparing mixes for duplication. It involves optimizing dynamics and tonal balance, matching the volume levels of all of the songs, and sequencing tracks.

Memory locations: Settings in Pro Tools that store information about specific edit points and selected track ranges.

Metadata: Metadata refers to general data that describes the attributes of a file, such as file name, creation date, file size, and so on. DigiBase collects metadata about audio files and other Pro Tools session-related files during the indexing process and stores this information in an associated database file.

MIDI: Musical Instrument Digital Interface. A communication protocol originally designed to allow synthesizers created by different manufacturers to communicate with each other.

MIDI cable: A cable that uses a five-pin connection standard to transmit MIDI information between MIDI devices such as sequencers, controllers, sound modules, keyboards, and effects.

MIDI interface: A hardware device that connects to a computer to send and receive MIDI.

MIDI keyboard: A device with piano- or organ-style keys that sends MIDI information when played.

MIDI region: A visual representation of a segment of MIDI data. MIDI Regions can be arranged in tracks in the same way as audio regions.

MIDI track: In Pro Tools, a channel that holds and controls MIDI note, instrument, and controller data.

Mixdown: The process of combining all tracks, edits, effects, and automation events into a final two-track master.

Modulation: A parameter of many delay effects that lets you adjust changes in delay time over time. Effects such as phase shifting, flanging, and chorus use short delay times with modulation.

N

Non-destructive editing: In Pro Tools, editing functions that let you change audio regions without altering their parent audio files.

The Nyquest Theorem: A basic rule of digital audio. It states that the sample rate must be twice the value of a sound’s highest frequency for that sound to be accurately reproduced. For example, CD audio is sampled at 44.1 kHz, whereas the human hearing range extends to only 20 kHz.

O

Omni-directional mic: A mic that captures sounds from all directions.

Optical connectors: Fiber-optic cables that transmit digital audio signals. They were originally developed to link Alesis ADATs to compatible gear. Also known as lightpipe.

Output selectors: Controls that let you route audio output to internal busses or external destinations (via the Pro Tools interface).

P

Parametric EQ: A tonal control (equalizer) that lets you target specific frequency ranges.

Performance volume: A performance volume is a storage volume that has been designated as suitable for recording and/or playback of media in a Pro Tools session.

Phantom power: A low-level electric current sent from the mic preamp to a condenser mic.

Phase cancellation: A type of audio interference that occurs when sound waves overlap and cancel each other out. This can cause frequencies to lose clarity or drop out.

Playlist: In Pro Tools, an arrangement of regions on an audio, MIDI or instrument track. A playlist can include a single region or multiple regions.

Precedence effect: The process by which humans locate sounds in a three-dimensional space: The ear that first hears a sound perceives it as significantly louder than the other ear does. Our two-ear auditory system uses this difference in perceived loudness to automatically triangulate the location of the sound source.

Punch recording: In Pro Tools, pressing (punching) the Record button in or out of Record mode at precise track locations. Used frequently during recording to redo unsatisfactory vocal or instrumental segments.

Q

Q: An adjustable parameter that determines the range of frequencies selected by a parametric EQ. The Q represents the number of octaves that the applied EQ affects.

Quantization distortion: Noise that occurs as a result of errors introduced when low-level audio signals are sampled or when digital audio is converted from higher to lower bit depths (such as when converting 24-bit audio to 16-bit for CD mastering).

Quantizing: The process of automatically changing the timing of a group of MIDI notes.

R

RCA plug: Unbalanced connectors used in most home stereo and video equipment. The tip is audio signal and the surrounding shield is ground. Also called phono plug.

Region: In Pro Tools, a visual representation—usually a waveform—of a parent audio file stored on disk. A region can be any length—from an entire audio file to a single verse, hook, bar, or note.

Region groups: Pro Tools lets you select multiple regions and place them together in a single region group. Region groups can help you keep your regions organized and speed up editing tasks.

Regions list: A list found in the Edit window that lets you manage the flow of audio and MIDI regions in and out of a Pro Tools session. When you record, import, or create a new region, it appears in the Regions list.

Reverb: A natural property of any enclosed room that occurs when sound waves bounce off walls, ceilings, and floors. Its three basic sound components are direct sound, early reflections, and reverberations.

Ribbon mic: An expensive and fragile mic that can produce a unique silky tone—the result of a slight roll-off that tends to occur in the high end. Ribbon mics were popular from the 1930s to the 1960s, but were pretty much replaced in the studio by condenser mics.

RTAS plug-ins: Digidesign’s Real-Time AudioSuite plug-ins use your computer’s CPU to process audio non-destructively in real time. They don’t change the original audio file saved on disk; effects are applied only during playback or when bouncing to disk.

S

Sample rate: The number of times per second that sound wave information is gathered, or sampled, during the digital audio recording process. Measured in kilohertz (kHz). Sample rate determines a recording’s frequency range and thus, its accuracy. Higher sample rates generally produce more accurate audio recordings.

Sampler: A sound generator that plays back individual sounds, or samples, when triggered by a MIDI note.

Scrub: A term borrowed from analog recording, scrubbing refers to running the tape manually back and forth over the playback head. It’s useful for locating edit points that might be difficult to find visually.

Sends: Channel strip controls that let you route audio to an internal bus or external output for effects processing or submixing.

Separation: The technique of using left/right panning to spread tracks out across the stereo image. Separation lets you hear tracks with more clarity and introduces the perception of width in the stereo image.

Sequencer: Hardware devices or computer programs that are used to record, edit, and play back MIDI data. Sequencers can work with not only MIDI notes, but controller and sysex data as well.

Session: A Pro Tools session is analogous to a session in a real-world recording studio: It contains all the elements you need to record, edit, process, mix, master, and store audio recordings.

Session file: When you start a new Pro Tools project, you create a new session file. A session file maps all the elements in a session, including audio files, MIDI data, edits, and mix information.

Side-chain processing: Audio signal routing that involves an effect on a track being triggered by audio from a different track.

Signal path: The way that audio is routed in, out, and through a Pro Tools session.

Sound module: A MIDI synthesizer without a keyboard.

S/PDIF: Sony/Phillips Digital Interface. A transmission format for digital audio devices. It’s commonly used in consumer devices. S/PDIF inputs and outputs generally have unbalanced RCA connectors.

Splice point: In Pro Tools, the location where two cross-faded regions join.

Stereo image: A simulation or image of a three-dimensional acoustic space that’s constructed during the creation of a stereo mix. Techniques such as left/right panning, spatial effects (reverb, delay, chorus, and flange), and EQ shaping help trick our two-ear auditory system into perceiving sound in the three dimensions of width, depth, and height.

Sub-paths: In Pro Tools, these are signal paths within the main path. For example, a main path stereo output has two mono sub-paths.

Submix: Created by merging multiple tracks of audio into a single track.

Synthesizer: An electronic instrument used to make sounds. There are many different kinds of synthesizers and different methods for synthesizing sounds, including analog, sample playback, wavetable, granular, physical modeling, and virtual analog synthesis.

Sysex data: System-exclusive data. Specialized MIDI data that manufacturers can use to define MIDI events and messages that work only with their MIDI devices.

T

Timeline ruler: In Pro Tools, a ruler that provides a timing reference for track material.

Timeline selection: In Pro Tools, a selection of a range of time in a Timebase ruler. Timeline selections automatically apply across all tracks in a session.

Track: A designated space in a recording system that’s assigned to carry a single audio signal. In Pro Tools, tracks let you direct the flow of audio into your system, through DSP effects, and then back out to your ears and/or mixdown machine.

Transfer volume: Transfer volumes are storage volumes that cannot be used by Pro Tools for recording or playback, such as a CD-ROM or network storage volume.

Transient: A sound that occurs for a brief time period, such as a drum hit, a piano note, or a guitar strum.

Transient peak: The instance of strongest attack in a transient. For example, a snare drum hit consists of a strong initial attack—a transient peak—followed by a period of decay.

TRS: Tip-ring-sleeve. A 1/4-inch stereo (two-channel) connector commonly found on headphones. The tip is left channel, the ring is right channel, and the sleeve is ground. TRS connectors can be used for balanced inputs and outputs. Sometimes called phone plugs.

TS: Tip-sleeve. A 1/4-inch unbalanced mono connector. The tip is audio signal and the sleeve is ground. It’s commonly used for electric guitars, keyboards, and other unbalanced line-level connections.

U

Unbalanced line: A cable with one conductor and a surrounding shield at ground potential. Unbalanced lines are more prone to pick up interference. As a result, they can add noise to a recording.

W

Waveform: A graph of an audio signal’s sound pressure level (in decibels) versus time.

X

XLR: A three-pin connection usually found on balanced microphone cables. It’s used for analog and digital (AES/EBU standard) audio signals. Also called a Canon connector.

Z

Zero crossing: In Pro Tools, the point at which a waveform crosses its center line, and the waveform’s amplitude is zero.