Glossary – P
Pad – 1) A device or circuit that attenuates an incoming signal, usually to prevent overload of an amplifier that follows along the signal path. (Also sometimes called “Attenuator pad.”) 2) A device with a surface that can be hit by a drum stick; hitting the pad produces an output signal pulse (or MIDI command) that causes a drum machine or synthesizer to sound a drum sound. 3) A type of synthesizer patch/program used to create sustained background or atmospheric sounds.
Pan (Panning) – The process of “placing” a particular sound within the stereo field. This is accomplished by controlling the balance of the signal between the left and right speakers so the ear hears the sound as coming from a particular point in the sonic space between left and right. This sonic space is sometimes called the “stereo panorama,” from which the word “panning” is derived. In surround sound, panning occurs in a 360° sound space, not just left-right.
Panpot (or Pan Pot) – Short for “Panoramic Potentiometer,” a panpot is a knob in the channel strip that controls the panning of the audio signal in the stereo (or surround) space by controlling how much of the signal is sent to each speaker or channel.
Parallel Jacks – Several jacks that are wired so that each connection is wired to the corresponding connection of other jacks.
Parallel Port – A connector that is able to transmit and receive digital data at the same time though different pins.
Parameter – Each characteristic of a sound, signal or device that is possible to change.
Parametric EQ – An equalizer in which all parameters of equalization can be adjusted to any amount, including the center frequency, the amount of boost or cut, and the bandwidth.
Partial – 1) Another word for overtone. 2) One of a number of sine waves that makes up a complex sound, helping to define the timbre. This concept is a key part of creating sounds in synthesizers: in additive synthesis, a number of partials are combined to create a certain tone.
Pass Band – The frequency range of signals that will be “passed” by a filter, rather than reduced.
Passive Device – A component that does not generate or control electrical current (as opposed to an “Active Device”). In audio applications, this usually refers to a piece of gear that does not include an amplifier as part of its design. For example, active speakers are self-powered, while passive speakers require an external amplifier in order to reproduce sound. (See also “Active Device.”)
Patch – 1) To route or reroute the signal in an audio system (such as a console) by using short cables with plugs inserted into jacks. 2) A sound setting or program on a synthesizer.
Patch Bay (or Patchbay, Patch Field, Patch Panel) – A panel or component containing a series of jacks with connections for most of the inputs and outputs of the console and components in the studio, used for the purpose of organizing, managing and regulating signal flow.
Patch Cord (or Patch Cable) – An insulated cable with plugs on each end used to route audio signals. Patch cords are typically thought of as short cables used to make connections in the patch bay (hence the name); however, patch cords facilitate almost any kind of audio connection between devices, can come in a wide range of lengths, and can include a number of different types of connectors.
Patch Field – See “Patch Bay.”
Patch Librarian – A computer program allowing for the storing of sound patches outside of a synthesizer via MIDI.
Patch Panel – See “Patch Bay.”
Path – Short for Signal Path, the way in which current does or may travel in a circuit or through a device.
PCM – See “Pulse Code Modulation.”
Peak Filter – An EQ circuit/filter that boosts or cuts the middle (center frequencies in an audio signal, as opposed to high-pass or low-pass filters. (NOT to be confused with amplitude peaks.)
Peak Meter – A meter which detects the absolute peak value of a waveform, as opposed to the RMS value. (See also “Peak Value,” “Root-Mean-Square,” “RMS Meter.”)
Peak-to-Peak Value – The measure of the total amplitude between positive and negative peaks in an audio signal. Equal to twice the peak value for a sine wave. (See also “Peak Value.”)
Peak Value (also called Peak Level) – The measure of the maximum positive or negative value (amplitude) of a waveform at any moment. In audio, this is visually depicted as the farthest point of the waveform above or below the zero axis.
Pedal Board – A board with several guitar pedals attached and inter-connected so that a guitar player can conveniently activate a number of different effects.
Phantom Power – A system used to supply DC voltage to condenser mics and other components through the audio cables, eliminating the need for external power supplies.
Phase – A measurement (expressed in degrees) of the time difference between two similar waveforms.
Phase Addition – The increased audio energy that happens when waveforms are in similar phase relationships, resulting in an increase in volume up to twice what it should be.
Phase Cancellation – The opposite of phase addition, this is the reduction of energy that occurs when two similar waveforms that are out of phase with one another and begin cancelling each other out, either greatly reducing or eliminating the volume. When two identical wave forms are completely out of phase (by 180 degrees), the result in theory is a total silencing or cancellation of the signal.
Phase Distortion – A change in the sound because of a phase shift in the signal. Sometimes used in synthesizers as a method of altering the wave shape or adding harmonics to the sound.
Phase Lock – Any of a number of processes used to help synchronize signals or devices by correcting phase differences. For example, in analog tape machines, phase locking helps to keep multiple machines synced together by sensing phase differences in the playback of pilot tunes by the two machines and adjusting the speed to eliminate the phase difference. In synthesizers, phase locking controls one tone generator so that it begins its waveform in phase with the signal from another tone generator. Phase-locked loops (PLL) are reference signals used in the clock functions of electronic devices.
Phase-Locked Loop (PLL) – See “Phase Lock.”
Phase Reversal – A change in a circuit to get the waveform to shift by 180 degrees.
Phase Shift – A delay introduced into an audio signal measured in degrees delayed.
Phasing – An effects sound created by varying the phase shift of an audio signal, then mixing it with the direct signal.
Phon – A unit of apparent loudness, numerically equal to the same number of dB as a tone playing at 1000 Hz. For example, a sound is said to be 60 phon if it is perceived to be as loud as a 1000-Hz tone playing at 60dB.
Phone Plug (Jack) – A plug (or its mating jack) with a diameter of 1/4 inch and a length of I 1/4 inches used for interconnecting audio.
Phono Plug – See “RCA Plug.”
Pickup – 1) A device on an electric guitar or other instrument that puts out an audio signal according to the string motion on the instrument. 2) See “Contact Microphone.”
Pickup Pattern – The shape of the area in front of or around the microphone from where it evenly picks up sound. Many use this term interchangeably with “polar pattern,” but a polar pattern gives more detail about microphone sensitivity. (See also “Polar Pattern.)
Pinch Roller – A rubber (or plastic) wheel on a tape recorder that pinches the tape between it and the capstan, allowing the capstan to pull the tape.
Ping-Ponging – See “Bouncing.”
Pink Noise – A noise signal similar to white noise, containing all audible frequencies, but with equal energy per octave as opposed to all frequency bands. Engineers frequently use pink noise as a tool to tune and calibrate audio equipment. (See also “White Noise.”)
Pitch – 1) The perception of frequency by the ear (a higher or lower tone of music). 2) A control on a tape transport which adjusts the speed slightly up or down, changing the pitch and time of the music.
Pitch Bend – A mechanism on a synth, keyboard or controller that can cause the pitch of the note to move up or down by a small amount.
Pitch-to-MIDI Converter – A device that detects pitch in an analog audio signal and translates it into MIDI information. (Also called “Audio-to-MIDI-Converter.”)
Pitch-to-Voltage Converter – A device that detects the frequency of an audio waveform and changes it into a control voltage, which is in turn fed to an oscillator that produces a pitch at the same frequency.
Plate Reverb – A device that produces artificial reverberation by sending vibrations across a metal plate via a transducer similar to a speaker driver. Physical plate reverbs today are considered a vintage form of artificial reverb; nowadays, most plate reverb effects are emulated digitally by plugins or reverb units.
Playback – 1) The reproduction of recorded audio. 2) In motion picture or video production, the reproduction of the music over loudspeakers so the performers/musicians can perform in time to the music for the camera.
Playback Head – A transducer that converts magnetic flux recorded on tape into an audio signal for playback.
Playback Mode – A configuration on a console that allows quick playback of the signal previously recorded on tape or via DAW via the monitor mixer.
Playlist – 1) See “Take.” 2) A user-defined selection of songs; a feature available on most streaming and digital media players.
Plug – A connector, usually on a cable, that mates with a jack.
Polar Pattern – 1) In microphones, a graphic display of the area around the microphone that is sensitive to sound waves, detailing the audio output levels in dB of sound arriving from different directions. Similar to “Pickup pattern,” but more specific. 2) In speakers, a graphic display of the speaker’s dispersion of sound.
Polarity – The direction of current flow or magnetizing force.
Polarizing Voltage – In condenser and electret microphones, the introduction of a small amount of electrical current to create the magnetism by which the capacitor converts audio signals to electrical current. In condenser microphones, polarizing voltage is provided externally (see also “Phantom Power”); in electret microphones, the polarizing voltage is permanently impressed on the condenser during manufacturing.
Pole Pieces – Iron or other magnetic material that conducts magnetic force for use in transducers like record heads, playback heads, microphones, speakers, etc.
Polyphonic – Able to play more than one pitch or “voice” at the same time. A term commonly used to describe synths and keyboards. (See also “Voice.”)
Ponging – See “Bouncing.”
Pop Filter – A device that is placed over a microphone or between the microphone and vocalist to prevent loud “pop” sounds created by the vocalist’s breath directed toward the microphone.
Port – 1) A connection point in computer or electronic device for transmitting and receiving digital data, similarly to how a jack receives and transmits audio signals. 2) An opening or vent in a speaker case that resonates with air movement in the speaker, used in bass reflex speakers and woofers to enhance low frequencies.
Portamento – A pitch change that smoothly glides from one pitch to another. Also refers to the synthesizer mode or MIDI command that allows or causes this to happen.
Post – Short for either “Post Production” or “Post-Fader.” (See both entries.)
Post-Fader – Refers to an aux send position or setting that places the send after the channel fader within the signal path. Sending a signal post-fader means the fader itself affects the level of the send signal, as opposed to pre-fader. (See also Pre-Fader.)
Post-Production – Refers to the work of adding tracks, editing and other fine tuning after primary recording or filming has taken place. Post-production in recording includes such things as additional overdubs, editing, mixing and mastering. Post-production in film includes a wide range of additional audio and visual effects. NOTE: We mention film in this context because film post-production includes a lot of audio work (e.g., voiceovers, foley, audio mixing and editing) to the point that many audio engineers are involved in film post-production as a full-time career.
Post-Roll – A segment of blank tape (or track silence, on a DAW) that runs past the end of the recording. (See also “Pre-Roll.”)
Pot – See “Potentiometer.”
Potentiometer – (Abbreviated “Pot“) Often thought of as a fancy word for “knob,” a potentiometer is basically any mechanism that controls input or output voltage by varying amounts (for example, panning a signal left/right, volume control, or the amount of signal sent to an aux send or bus. Potentiometers can be knobs or faders, meaning that almost every control on a console that isn’t a button or switch is a potentiometer. However, many engineers commonly refer to faders as “faders” and knobs as “pots.”
Power Amplifier – (abbreviated “Power Amp”) A device that amplifies a line level signal to drive a speaker or set of speakers. (See also “Line Level.”)
Preamplifier or Preamp – A low-noise amplifier designed to take a low-level signal (for example, from a microphone) and bring it up to normal line level before sending it into the mixing console.
Pre/Post Switch – A switch on the input module that determines whether the send control comes before or after the main channel fader in the signal path (See also “Pre-Fader,” “Post-Fader.”)
Precedence Effect – See “Haas Effect.”
Pre-Delay – A parameter on a reverb unit or plugin that determines the amount of time (delay) between the original dry sound and the early reflections of reverberation. This feature is often used to simulate the natural acoustic properties of a room, but can also be used to create interesting unnatural effects.
Pre-Echo – (Also called “Forward Echo”) A compression artifact that often occurs in digital audio in which an “echo” of a sound (or part of a sound) is heard ahead of the sound itself, often due to the data inconsistencies in certain compressed digital formats. A type of pre-echo can also sometimes occur in the end product of a recording, occurring on tape as a result of low-level leakage caused by print-through, and also on vinyl records due to physical differences and/or deformities in the grooves between silence and a loud transient. In digital formats, pre-echo is generally an unwanted problem that requires additional signal processing to resolve—but in some cases it can also be used on purpose as a sound effect (not to be confused with “Reverse Echo”).
Pre Emphasis –A boosting of high frequencies during the recording process to keep the audible signal above the noise floor.
Pre Fader – Refers to an aux send position or setting that places the send before the channel fader within the signal path. Sending a signal pre-fader means the fader does not affect the level of the send signal, as opposed to pre-fader.
Pre-Fade Listen (PFL) – A function on the channel strip of a mixer or DAW that allows a channel signal to be heard and often metered before the channel fader.
Premix –1) The process of mixing a set of tracks as group, then managing the mixed group in the context of the other tracks by routing them to an auxiliary channel. Consolidating tracks by bouncing is a form of premixing, but a premix is not necessarily pre-recorded. (See also “Bouncing.”) 2) An important part of film post-production in which the process of mixing a section of audio for combination with the others. Dialogue, Foley, SFX and music may all be premixed before being combined together under the video.
Presence – 1) In amplification and mixing, the boosting of upper-mid frequencies to cause a sound or instrument to cut through, creating the impression that the sound source is more “present,” right next to the listener. 2) See “Room Tone.”
Presence Frequencies – The range of audio frequencies between 4 kHz and 6 kHz that when boosted, can increase the sense of presence, especially on voices.
Preset – A factory programmed set of parameters on a synth, signal processor, plug-in or other electronic device.
Pressure-Gradient Microphone – (Also called “Velocity Microphone“) A microphone whose diaphragm is exposed front and back, with diaphragm movement being caused by the pressure difference between its front and back. This creates a bi-directional or “figure-8” pickup pattern (See also “Bi-Directional Pattern.”)
Pressure Microphone (Also called “pressure operative microphone”) – A microphone whose diaphragm responds to incoming sound wave pressure as it works against the normal or controlled air pressure inside the microphone case. This design makes the diaphragm sensitive to pressure regardless of direction, giving it an omnidirectional pickup pattern. (See also “Omnidirectional Pattern.”)
Pressure Sensitivity – See “Aftertouch.”
Pressure Zone Microphone – See “Boundary Microphone.”
Print Through – The unwanted transfer of magnetic flux from one layer of analog tape to another.
Processing – See “Signal Processor.”
Processor – See “CPU.”
Producer – In music, the producer is the director of an audio recording project; the person responsible for getting a final product of desired quality within a budget.
Production – 1) The collective actions that go into producing music. 2) Describing the quality of a recording—the end result of production decisions during the recording and mixing process.
Production Studio – Broadly speaking, any space dedicated to production within the arts, for example, film/video, animation or post production. In the context of audio, a production studio is effectively a recording studio that specializes in the assembly and mixing of commercials and radio programs from pre recorded music and effects with newly recorded dialogue.
Program Change – A MIDI message that tells the receiving device to change presets.
Programmable – Able to have the parameters changed by the user, especially in a computer controlled device.
Prompt – A set of instructions for the user to follow, which appears on a computer screen.
Protocol – In digital and information technology, a set of rules governing the structuring and transmitting of data in a standardized format so all related devices can properly interpret the data.
Pro Tools – Avid’s trade name for its digital audio workstation (DAW) that has become an industry standard in professional recording studios.
Proximity Effect – The natural boost in the microphone’s output for bass frequencies as the mic is placed closer to the sound source.
Psychoacoustics – The study of how humans perceive and respond to sound, not just in the context of interpreting the physical sound waves, but also taking psychological and emotional factors into account. This branch of science is helpful to audio engineers in understanding how the brain interprets various sounds and frequencies.
Puck – Any circular piece of metal, fiber, rubber, etc., which drives something from a rotating power source. A common example in the recording studio is the puck in a rotating Leslie speaker.
Pulse – 1) The steady beat in music based on its tempo, whether audible or perceived. 2) A type of sound wave commonly created and manipulated by synthesizers whose waveform is characterized by sharp rises and drops in amplitude like a square wave, but whose peaks are shorter than its troughs, giving the wave a pulse-like feel. Also called “Pulse Wave.”
Pulse Code Modulation (PCM) – A process by which analog signals are translated to digital code. This is done by taking samples of the amplitude of the analog signal at regular rapid intervals, then translating it into binary numbers as a digital representation of the original signal. The faster the sample rate, the better the digital reproduction. PCM is the most common form of A/D conversion in digital audio.
Pulse-Width Modulation (PWM) – In synthesized music, the process of using a control voltage to vary the width of a pulse wave form, essentially switching between square waves and pulse waves. This has the effect of creating richer timbres, giving sounds a thicker, more lush feel, or of giving a digital sound more analog properties.
Pumping and Breathing – In studio jargon, an effect created when a compressor is rapidly compressing and releasing the sound, creating audible changes in the signal level. “Pumping” generally refers to the audible increase of sound levels after compression has taken place; “breathing” refers to a similar effect with vocals, raising the signal volume just as the vocalist is inhaling. Pumping and breathing is a sign of cheap compression or over-compression, and is usually undesirable, although some engineers and musicians use it on purpose occasionally to create a particular effect.
Punch In/Punch Out Recording – The process of activating and/or deactivating the record function on tape or DAW during playback of a passage, usually as the performer plays/sings along. This can be used either as a method of doing quick overdubs, or as a way of getting a better take on a certain passage without having to start the track from the beginning.
Pure Tone – A tone consisting of only the fundamental frequency with no overtones or harmonics, graphically represented as a simple sine wave.
PZM – Abbreviation for Crown Audio’s Pressure Zone Microphone. (See also “Boundary Microphone.”)