P

Parametric EQ
Equalization with three adjustable parameters: center frequency, gain (±dB), Q (bandwidth). Most precise EQ type. Essential in DSP tuning. Example: -6 dB at 60 Hz, Q=3.0 to notch cabin resonance. → See also: Q Factor, EQ
Chapter 4.5

Passive Crossover
Inductor/capacitor network dividing frequency bands after amplification. Included with component speakers. Simple but inferior to active crossovers: insertion loss, limited adjustability, component tolerance issues. → See also: Active Crossover
Chapter 1.2

Phase
Time relationship between two signals. In-phase: peaks align. Out-of-phase (180°): peaks and troughs swapped, cancellation occurs. Critical at crossover frequencies. Subwoofer phase: 0° or 180° switch on amplifier. → See also: Polarity
Chapter 4.3

Polarity
Electrical connection direction. Positive to positive, negative to negative = correct polarity. Reversed polarity = phase inverted 180°. Test with 9V battery: cone should move outward. → See also: Phase
Chapter 4.3

Ported (Bass Reflex) Enclosure
Subwoofer enclosure with port (tube or slot). Port resonates at tuning frequency (Fb), increasing efficiency 3-6 dB at Fb. Requires larger box than sealed for same driver. Needs subsonic filter. → See also: Fb, Subsonic
Chapter 10.3

Preamp Output
Low-level RCA output from head unit to amplifiers. Voltage: 2V (adequate), 4V (good), 5-6V (excellent). Higher voltage = better signal-to-noise ratio. → See also: RCA, Gain Staging
Chapter 5.1