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p - rho) Density of air at STP 1.18 kg/m^3 |
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Pa - Acoustical power |
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Parallel Circuit - A circuit configuration in which the same voltage
is applied to all components, with current divided among the components
according to their respective resistances or impedances.
Example: All positive leads of two or more speakers
connected together and all negative leads connected together. |
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Parametric - A type of equalizer with adjustable parameters
such as center frequency and bandwidth (Q) as well as amplitude. |
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Passive Arming - The ability of some security systems to arm without requiring any direct action from the operator of the vehicle. |
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Pe - Electrical power |
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Peta (P) - A prefix meaning 1015 or 1,000,000,000,000,000 |
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Phase - The relative position of two sound waves with
respect to each other. |
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Phase Shift - Frequency interaction in the crossover region of passive crossovers which can cause some frequencies to be delayed with respect to other frequencies. |
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Photo Detector (photo diode) - A semiconductor device which
provides variations in current as a function of light intensity. |
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Piezo Electric Tweeter - A very efficient, highly directional tweeter
which operates without a crossover or magnet. Driver creates sound when a
quartz crystal receives electrical energy. |
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Pink Noise - Sound with all frequencies perceptible to the human
ear reduced to an equal energy level. |
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Pink Noise Generator - A device used to generate pink noise that
usually includes a calibrated microphone. |
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Pinswitch - A simple spring-loaded mechanical switch used in many different vehicles designed to turn on interior lights when doors are opened. Pinswitches are also used in the installation of most security systems in the hood or trunk/hatch as a means of triggering the system should these points be opened |
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Pit - One of the depressions that represents data in a compact disc.
May also be referred to as bumps, this is what the pick up sees. |
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Plate Speaker - A speaker that has two drivers mounted side by side on a flat surface. |
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Polarity - The electrical quality of having two opposite poles, one positive and
one negative. Polarity determines the direction in which a current tends to flow. |
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Pole Mount - A common automotive speaker design with the high frequency
driver mounted on a center pole. Newer designs mount the high frequency driver in the
same location above the lower frequency driver with a bridge. This prevents problems
such as dust and dirt from entering at the base of the pole. |
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Potentiometer - A variable resistor made with either carbon or wire wound material which attenuates a signal. |
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Power Handling Capability - The maximum amount of power that can be
safely accommodated without damage in a speaker system. This will vary depending
on frequency and length of time the signal is applied. |
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Pre-amp Fader - A circuit that allows effective level control of two amplifiers,
built in and external without loss of power. |
| • |
Pre-amplifier (pre-amp) - The circuit which takes a small signal and amplifies it to be
fed into the power amplifier for further amplification. Contains controls for volume,
regulating tone, and channel balance. |
