MartinLogan Montis Manuel De L'utilisateur page 41

Passive crossover. Uses no active components (transistors, IC's,
tubes) and needs no power supply (AC, DC, battery) to operate.
The crossover in a typical loudspeaker is of the passive variety.
Passive crossovers consist of capacitors, inductors and resistors.
Phase. The amount by which one sine wave leads or lags a sec-
ond wave of the same frequency. The difference is described by
the term phase angle. Sine waves in phase reinforce each other;
those out of phase cancel.
Pink noise. A random noise used in measurements, as it has the
same amount of energy in each octave.
Polarity. The condition of being positive or negative with respect
to some reference point or object.
RMS. Abbreviation for root mean square. The effective value of a
given waveform is its RMS value. Acoustic power is proportional
to the square of the RMS sound pressure.
Resistance. That property of a conductor by which it opposes the
flow of electric current, resulting in the generation of heat in the
conducting material, usually expressed in ohms.
Resistor. A device used in a circuit to provide resistance.
Resonance. The effect produced when the natural vibration fre-
quency of a body is greatly amplified by reinforcing vibrations at
the same or nearly the same frequency from another body.
Sensitivity. The volume of sound delivered for a given electrical
input.
Stator. The fixed part forming the reference for the moving dia-
phragm in a planar speaker.
THD. The abbreviation for total harmonic distortion. (See
Distortion)
TIM. The abbreviation for transient intermodulation distortion.
Transducer. Any of various devices that transmit energy from one
system to another, sometimes one that converts the energy in
form. Loudspeaker transducers convert electrical energy into
mechanical motion.
Transient. Applies to that which lasts or stays but a short time. A
change from one steady-state condition to another.
Tweeter. A small drive unit designed to reproduce only
high frequencies.
Wavelength. The distance measured in the direction of progres-
sion of a wave, from any given point characterized by the same
phase.
White noise. A random noise used in measurements, as it has the
same amount of energy at each frequency.
Woofer. A drive unit operating in the bass frequencies only. Drive
units in two-way systems are not true woofers but are more
accurately described as being mid/bass drivers.
Glossary of Audio Terms 41