P

Pain Threshold
A sound intensity level sufficiently high to produce the sensation of pain in the human ear, usually about 120dB.

Particle Velocity
The velocity of an infinitely small part of a medium, say air, through which the sound wave travels.

Peak level
The maximum instantaneous level of an impulsive or transient sound, or the maximum level, in a specified time interval, of a sound of long duration.

Pink Noise
Noise signal obtained by feeding a white noise signal through a filter that decreases the spectrum level by 3 dB for each octave or doubling of frequency. The spectrum level of pink noise is constant as a function of frequency.

Pitch
A subjective term for the perceived frequency of a tone.

Pressure Zone
As sound waves strike a solid surface, the particle velocity is zero at the surface and the pressure is high, thus creating a high-pressure layer near the surface.