Glossary
AC. Abbreviation for alternating current.
Active crossover. Uses active devices (transistors, IC’s, tubes) and some form of power supply to operate.
Amplitude. The extreme range of a signal. Usually measured from the average to the extreme.
Arc. The visible sparks generated by an electrical discharge.
Bass. The lowest frequencies of sound.
Capacitance. That property of a capacitor which determines how much charge can be stored in it for a given potential difference between its terminals, measured in farads, by the ratio of the charge stored to the potential difference.
Capacitor. A device consisting of two or more conducting plates separated from one another by an insulating material and used for storing an electrical charge. Sometimes called a condenser.
Clipping. Distortion of a signal by its being chopped off. An overload problem caused by pushing an amplifier beyond its capabilities. The
Crossover. An electrical circuit that divides a full bandwidth signal into the desired frequency bands for the loudspeaker components.
dB (decibel). A numerical expres- sion of the relative loudness of a sound. The difference in decibels between two sounds is ten times the common logarithm of the ratio of their power levels.
DC. Abbreviation for direct current.
Diffraction. The breaking up of a sound wave caused by some type of mechanical interference such as a cabinet edge, grill frame, or other similar object.
Diaphragm. A thin flexible mem- brane or cone that vibrates in response to electrical signals to produce sound waves.
Distortion. Usually referred to in terms of total harmonic distortion (THD) which is the percentage of unwanted harmonics of the drive signal present with the wanted signal. Generally used to mean any unwanted change introduced by the device under question.
Driver. See transducer.
Dynamic Range. The range between the quietest and the loudest sounds a device can handle (often quoted in dB).
Efficiency. The acoustic power delivered for a given electrical input. Often expressed as decibels/watt/meter (dB/w/m).
ESL. Abbreviation for electrostatic loudspeaker.
Headroom. The difference, in decibels, between the peak and RMS levels in program material.
Hybrid. A product created by the marriage of two different tech- nologies. Meant here as the combination of a dynamic woofer with an electrostatic transducer.
Hz (Hertz). Unit of frequency equivalent to the number of cycles per second.
Imaging. To make a representation or imitation of the original sonic event.
Impedance. The total opposition offered by an electric circuit to the flow of an alternating current of a single frequency. It is a combina- tion of resistance and reactance and is measured in ohms. Remember that a speaker’s impedance changes with frequency, it is not a constant value.
Inductance. The property of an electric circuit by which a varying current in it produces a varying magnetic field that introduces voltages in the same circuit or in a nearby circuit. It is measured in henrys.
Inductor. A device designed prima- rily to introduce inductance into an electric circuit. Sometimes called a choke or coil.
Linearity. The extent to which any signal handling process is accomplished without amplitude distortion.
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