| Term | Definition |
|---|---|
| AB Test | A test between two components. For example, a test between two different pre-amplifiers. For the test to be scientifically valid, the levels should be matched. |
| ABX Comparator | A device that randomly selects between two components being tested. The listener does not know which device is being listened to. |
| AC3 | See Dolby Digital. |
| Acoustic suspension | A sealed or closed box speaker enclosure. |
| AES/EBU | Balanced digital connection. For example, used to connect a CD transport to a DAC. The AES/EBU standard uses XLR type connectors. |
| Alignment | A class of enclosure parameters that provides optimum performance for a woofer with a given value of Q. |
| Alpha | Term used in sealed enclosure designs to mean the ratio of Vas to Vb, where Vb is the volume of the box you will build. |
| Alternating Current (AC) | An electrical current that periodically changes in magnitude and direction. |
| Ambience | The acoustic characteristics of a space with regard to reverberation. A room with a lot of reverb is said to be "live"; one without much reverb is "dead." |
| Ampere (A) | The unit of measurement for electrical current in coulombs per second. There is one ampere in a circuit that has one-ohm resistance when one volt is applied to the circuit. For more information, see Ohms Law. |
| Amplifier (Amp) | A device, which increases signal level. Many types of amplifiers are used in audio systems. Amplifiers typically increase voltage, current or both. |
| Amplifier classes | Audio power amplifiers are classified primarily by the design of the output stage. Classification is based on the amount of time the output devices operate during each cycle of signal swing. Also defined in terms of output bias current, (the amount of current flowing in... Read More |
| Analog | Before digital, the way all sound was reproduced. |
| Aperiodic | Refers to a type of bass-cabinet loading. An aperiodic enclosure type usually features a very restrictive, (damped), port. The purpose of this restrictive port is not to extend bass response, but lower the Q of the system and reduce the impedance peak at resonance... Read More |
| Attenuate | To reduce in level. |
| Audiophile | A person obsessed with the reproduction of music at the highest level of fidelity. Prone to irrational equipment changes based on subjective reviews of equipment with no relevance to their musical tastes and desires. |
| AWS | Adaptive Woofer System, trademark of ACI. An active woofer system with built in user adjustable equalization capabilities. |
| Baffle | A surface used to mount a loudspeaker. |
| Balanced | Referring to wiring: Audio signals require two wires. In an unbalanced line, the shield is one of those wires. In a balanced line, there are two wires plus the shield. For the system to be balanced requires balanced electronics and usually employs XLR connectors. Balanced lines... Read More |
| Balanced Armature | Usually used only in in-ear monitors such as Etymotic, Shure, Sensaphonics, and Ultimate Ears. They generally are limited at the extremes of the hearing spectrum (<16 kilohertz, >50 hertz) and require a seal more than other types of drivers to deliver their full... Read More |
| Band-pass Enclosure | A multi-chambered ported system. |
| Band-pass filter | An electric circuit designed to pass only middle frequencies. |
| Bandwidth | The total frequency range of any system. Usually specified as something like: 20-20,000Hz plus or minus three db. |
| Bass Blockers | Commercial name for auto-sound first order high pass crossovers (non-polarized capacitors), generally used on midbass or dash speakers to keep them from trying to reproduce deep bass. |
| Bass Reflex | A type of loudspeaker that uses a port or duct to augment the low-frequency response. Opinions vary widely over the "best" type of bass cabinet, but much has to do with how well a given design, such as a bass reflex is implemented. |
