**Parameter** an attribute with a value - for example, weighting.

On the other hand an object, like a cricket ball experiences acceleration, velocity and displacement literally so the general acceleration, displacement and velocity terms are more apt.

**Particle Velocity** the particles of a medium are displaced from their random motion in the presence of a sound wave. The velocity of a particle during this displacement is called the particle velocity, units m/s.

**Particle velocity** is the speed of the particle and should not to be confused with the speed of sound.

**Particle Velocity** is related to the Particle Displacement and Particle Acceleration - as described above.

**Particle Velocity** multiplied by the Sound Pressure =
Sound Intensity.

● Note 1 : unless otherwise specified, the reference velocity is 1 nm/s.

● Note 2 : unless otherwise specified, the velocities are understood to be expressed in root-mean-square values.

**Particle Velocity Level : Lv** = 20 lg (v/vo) dB re 5 x 10^{-8} m/s and is also known as **Sound Velocity Level : SVL**

**Reference Particle Velocity : vo** = 5·10^{-8} m/s ≡ 0 dB

If measurements are made in 3-axis then the resultant PPV (Peak Particle Velocity) is the vector sum i.e. the square root of the summed squares of the maximum velocities, regardless of when in the time history those occur. See also : Peak Particle Velocity instrumentation

See also : Volume Velocity and the **IEC Definition** of Level

1 Pa = 1 N/m^{2} = 1 J/m^{3} = 10^{-5} bar : kg·m^{-1}·s^{-2}

1 μPa = 1 micropascal = 10^{-6} Pa

Peak Frequency-weighted Sound Pressure Level

If measurements are made in 3-axis then the resultant PPV is the vector sum = the square root of the summed squares of the maximum velocities, regardless of when in the time history those occur.

See also PPV measurements.

● Note : if frequency weighting is not specified, the A-frequency weighting is understood.

See also the Noy

● Note 1 : the adjustment is described in ISO 3891-1978; it may vary from 0 dB to 6.7 dB.

● Note 2 : the adjustment purports to account for the extra subjective noisiness caused by pronounced audible tones such as may be generated by propeller, compressors, turbines or fans.

Permanent Threshold Shift : PTS

Personal Sound Exposure Meter : PSEM

See also : Sones

**pico : p** a SI prefix = 10^{-12} see other SI Units

**Picocoulomb : pC** 1 pC = 10^{-12} Coulomb

**Picofarad : pF** a million millionth of a Farad, 10^{-12} farad

**Picowatt : pW** a million millionth of a Watt; 10^{-12} farad

**Piezotron ®** trade name for IEPE - Integrated Electronics PiezoElectric.

This is useful when using sound analysers with constant percentage bandwidth octave or third-octave filters, the net result is a flat spectrum

Related Terms :
Broadband Noise •
Narrowband Noise •
Random Noise •
White Noise

See also :
Constant Bandwidth •
Constant Percentage Bandwidths •
Octave Bands •
FFT- Fast Fourier Transform.

See also : Tone

Some Planning Policy Guidance is available for downloading

PNC : Preferred Noise Criterion

PNLmax : Perceived Maximum Noise Level

PNR : Predicted Noise Level Reduction

See also : Line Source

Potential Sound Energy Density.

See also : Sound Power and Related Parameters.

Power Density

Power Level

Power Reference Levels

See also other types of averaging

PPG : Planning Policy Guidance 24

Frequency | Octave | 1/3 octave | Frequency | Octave | 1/3 octave | Frequency | Octave | 1/3 octave | ||
---|---|---|---|---|---|---|---|---|---|---|

16 Hz | x | x | ||||||||

20 Hz | x | 200 Hz | x | 2000 Hz | x | x | ||||

25 Hz | x | 250 Hz | x | x | 2500 Hz | x | ||||

3.15 Hz | x | x | 315 Hz | x | 3150 Hz | x | ||||

40 Hz | x | 400 Hz | x | 4000 Hz | x | x | ||||

50 Hz | x | 500 Hz | x | x | 5000 Hz | x | ||||

63 Hz | x | x | 630 Hz | x | 6300 Hz | x | ||||

80 Hz | x | 800 Hz | x | 8000 Hz | x | x | ||||

100 Hz | x | 1000 Hz | x | x | 10000 Hz | x | ||||

125 Hz | x | x | 1250 Hz | x | 12500 Hz | x | ||||

160 Hz | x | 1600 Hz | x | 16000 Hz | x | x |

Preferred Speech Interference Level : PSIL

See also : Atmospheric Pressure • Static Pressure • Sound Pressure and Related Parameters

Pressure Index

Pressure Intensity Index

See also : Free-field Microphones • Random Incidence Microphones

Pressure Residual Intensity Index

**Propagation** see Sound Propagation

PSEM, Personal Sound Exposure Meter

PSIL : Preferred Speech Interference Level

PTS : Permanent Threshold Shift