Martin Logan Illusion ESL C54A Mode D'emploi page 59

Inductor. A device designed primarily to introduce induc-
tance into an electrical circuit. Sometimes called a choke or
coil.
Linearity. The extent to which any signal handling process is
accomplished without amplitude distortion.
Midrange. The middle frequencies where the ear is the most
sensitive.
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 pas-
sive variety. Passive crossovers consist of capacitors, inductors
and resistors.
Phase. The amount by which one sine wave leads or lags
a second wave of the same frequency. The difference is
described by the term phase angle. Sine waves in phase rein-
force 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 pro-
portional 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 electri-
cal input.
Stator. The fixed part forming the reference for the moving
diaphragm 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 ener-
gy 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 pro-
gression 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.
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