Parameter
A user-adjustable quantity that governs some aspect of a device's performance. Normally, the settings for all of the parameters that make up a synthesizer patch can be changed by the user and stored in memory, but the parameters themselves are defined by the operating system and cannot be altered.

Parametric Equalizer
A type of equalizer that provides control over each filter's frequency and the amount of cut or boost of each filter. Typically, parametric equalizer's provide three to four filters that work in parallel, each one filtering a different frequency of the spectrum (i.e. low, mid, high). While parametric equalizers generally have fewer filters than a graphic equalizer, they are more flexible and provide finer control, due to the adjustability of the filtered frequencies.

Partial
One of the sine-wave components (the fundamental, an overtone, or a tone at some other frequency) of a complex tone; see overtone.

Patch
Refers to an instrument sound, program or voice on a synthesizer or sampler. This term comes from the roots of hardware synthesis, where physical cables where used to connect and route signals in a matrix to create a unique sound (same concept as phone operators "patching" a call through, back in the day).

PCM
Pulse Code Modulation. An uncompressed encoding method for digital audio, which is the way audio is stored on music CDs.

percentage quantization
A method of quantization in which notes recorded into a sequencer with uneven rhythms are not shifted all the way to their theoretically perfect timings but instead are shifted part of the way, with the amount of shift being dependent on the user-selected percentage (quantization strength). > quantization.

Phase
Also called "phase position" or "phase angle"; specified in 0 to 360. It describes an attribute of an oscillation that is especially significant when signals overlap.

physical modeling synthesis
A type of sound synthesis performed by computer models of instruments. These models are sets of complex equations that describe the physical properties of an instrument (such as the shape of the bell and the density of the material) and the way a musician interacts with it (blow, pluck, or hit, for example).

pitch-bend
A shift in a note's pitch, usually in small increments, caused by the movement of a pitch-bend wheel or lever; also, the MIDI data used to create such a shift. See bend.

pitch-shift
To change the pitch of a sound without changing its duration, as opposed to pitch-transpose, which changes both. Some people use the two terms interchangeably.

Playlist
A listing of songs quequed up to be played in order. A playlist can also be configured or/and saved for reuse.

Plug-in
Modular expansion software that enhance the capabilities of another program.
The "client program" is used to expand the functionality of a "host program", such as a sequencer or digital audio editor. The host provides the plug-in with some type of input data such as digital audio samples, which is then processed to generate new output, such as effected digital audio. The Winamp player uses plug-ins to add special audio or visual effects. Two popular plug-in formats used in computer music and audio are DirectX and VST digital audio plug-ins.

Pole
A portion of a filter circuit. The more poles a filter has, the more abrupt its cutoff slope will be. Each pole causes a slope of 6 dB per octave; typical filter configurations are two-pole (12 dB/oct) and four-pole (24 dB/oct). > rolloff.

poly mode
A MIDI reception mode in which a module responds to note messages on only one channel, and plays as many of these notes at a time (polyphonically) as it can.

Polyphonic
More than one note of an instrument sound may be played at the same time. Hardware and software synthesizers usually range from 1 to 128 notes polyphony. The number specifies exactly how many notes may be played at once before cutting-off previously played notes. An instrument that can play only one is said to be Monophonic.

poly pressure
Polyphonic pressure. (Also called key pressure.) A type of MIDI channel message in which each key senses and transmits pressure data independently. Compare with channel pressure.

Polytimbral
More than one instrument sound (timbre) may be played at the same time. Multitimbral is the more commonly used term for this functionality.

Potentiometer (Pot)
A variable resistor (rotary or linear) used to control volume, tone, or other function of an electronic device.

PPQN
Short for "Pulses Per Quarter Note" - Determines how many increments a quarter note is divided into; essential for sequencer timing, among others.

Program crash
Unfortunately, not a mystery to any computer user.