B - Refer to Magnetic Flux Density
BI - Electro-magnetic force factor.
BL - Driver motor strength.
Back-up Battery - A separate battery added to the security system as an alternate power supply to serve as a back up in case the vehicles main battery is disabled by a thief. Back-up batteries are typically the lead0acid gel cell type and are most effective when hidden from detection.
Baffle - In car audio this is the surface a driver is mounted to that separates the front wave from the back wave of the driver. An infinite baffle is simply the mounting surface of the driver when in a free air application.
Balance - The relative volume level between two channels, usually the left and right channels. May also refer to the relative volume between front and rear channels of an audio system. To make the same or equal.
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 are less apt to pick up external noise. This is usually not a factor in home audio, but is a factor in professional audio requiring hundreds or even thousands of feet of cabling. Many higher quality home audio cables terminated with RCA jacks are balanced designs using two conductors and a shield instead of one conductor plus shield.
Ballast - An inductor is very common in line-frequency ballasts to provide the proper starting and operating electrical condition to power a fluorescent lamp, neon lamp, or high intensity discharge (HID) lamp. (Because of the use of the inductor, such ballasts are usually called magnetic ballasts.)
Ballast Wire - The name given to a special resistance wire used between the ignition switch and the engine’s high voltage coil. This wire is typically composed of a carbon compound instead of normal copper.
Bandpass Enclosure - An enclosure with dual chambers enclosing the entire subwoofer, the patent for a bandpass enclosure was issued to Andre d’Alton in 1934. Typically one chamber sealed and the other vented, while the vented enclosure acts as a high-frequency attenuator or low-pass filter controlling the dB per octave roll-off.
Bandpass Filter - A device which incorporates both high-pass and low-pass filters in order to limit and attenuate both ends of the frequency range.
Bandwidth - Refers to the “space” in the frequency response of a device through which audio and/or data signals can pass (between lower and upper frequency limits; in audio applications those points where the signal level has rolled off 3 dB).
Barium Ferrite - A type of magnetic material used widely in car audio speakers, subwoofers, and/or driver motor structures. The material is made from alloy with iron and barium for improved magnetic strength.
Basket - The “frame” or “carriage” that holds the components (Cone, Voice Coil, Motor Structure, etc.) of a subwoofer in place.
Bass - Is a word used to describe the low end frequencies played in music, normally considered to be between the 60 Hz to 250 Hz range. Most popular music uses bass to provide harmonic and rhythmic support (most modern music tracks bass signals are around 90-200Hz), usually playing the root or fifth of the chord and stressing the strong beats. Boosting the 250 Hz frequency can add a feeling of warmth to the bass without loss of definition.
Bass Blocker - Commercial name for auto-sound first order high pass crossovers (non-polarized capacitors), generally used on smaller speakers to attenuate low mid/low frequencies.
Bass Boost - Boost a given input signal feature, and is offered on some aftermarket source units and subwoofer amplifiers. Some amplifiers offer an externally mounted bass boost controller for convenience of lowering the bass level. The bass boost must be tuned into the audio system when turned to its peak volume, this way the user can back the volume down but not increase it.
Bass Reflex - A vented enclosure that allows control of rear radiated sound waves. The area and length of the opening(s) are critical to optimum low frequency performance.
Battery - An electrically connected group of cells, wired in series, that stores an electrical charge and supplies a direct current (DC).
BBE Processor - A signal processing circuit that provides improvements in imaging and spatial realism by altering the frequency and phase characteristics of portions of the input signal.
BCM - Refer to Body Control Module
Beaming - The tendency of a loudspeaker to concentrate the sound in a narrow path instead of spreading it.
Bessel Crossover - A type of crossover design characterized by having a linear or maximally flat phase response. Linear phase response results in constant time-delay (all frequencies within the passband are delayed the same amount). Consequently the value of linear phase is it reproduces a near-perfect step response with no overshoot or ringing. The downside of the Bessel is a slow roll-off rate. The same circuit complexity in a Butterworth response rolls off much faster (steeper).
Best Tuning Memory (BTM) - A feature in which the tuner selects radio stations by signal strength, and assigns them to presets in numerical order, according to their frequency value.
Bezel – The trim piece that often covers the exterior edges of a car stereo and other dash components. Typically made of plastic and attached to the dashboard as a factory dress piece.
Bi-Amping - Is the process of using two amplifiers, one on either side of crossover frequency ranges, i. e. one amplifier for lows and the other for highs. This setup may also be utilized to separate tweeters from speakers in an active crossover application, where the speakers are on one amp and the tweeters are powered by another. By-Amping is not entirely possible when using a passive crossover setup.
Bias - Known as an unbalanced sound level. An unbalanced sound level, often used in the term “side biased” where the left and right channels are not equally perceived by the listener, usually because they sit closer to one side or the other in the car.
Binary Digit (BIT) - The smallest unit of data in a digital signal represented by either a one or zero.
Binary Code - Information that is presented as a numeric bitstream of ones and zero's. The language of digital media.
BL - The magnetic strength of the motor structure. Expressed in Tesla meters, this is a measurement of the motor strength of a speaker. Think of this as how good a weightlifter the transducer is. A measured mass is applied to the cone forcing it back while the current required for the motor to force the mass back is measured. The formula is mass in grams divided by the current in amperes. A high BL figure indicates a very strong transducer that moves the cone with authority.
Bluetooth - A short-range protocol that allows wireless connections in the 2.4GHz spectrum between compatible devices with range of 30 feet. While it’s often associated with hands-free mobile phone usage, depending on the Bluetooth profiles of two devices, the applications can extend to virtually any kind of data or command exchanges wirelessly.
Bluetooth Profile - The specific operational characteristic intended to provide the scope of how a Bluetooth device behaves. Two Bluetooth devices must support compatible profiles to be able to connect, or “pair.”
Body Control Module (BCM) - Is a generic term for an electronic control unit responsible for monitoring and controlling various electronic accessories in a vehicle's body. Typically in a car the BCM controls the power windows, power mirrors, air conditioning, immobilizer system, central locking, etc. The BCM communicates with other on-board computers via the car's vehicle bus, and its main application is controlling load drivers – actuating relays that in turn perform actions in the vehicle such as locking the doors or dimming the salon overhead lamp.
Bojo Tools - A brand name of fiberglass reinforced plastic (FRP) pry tools that are “non marring” to sensitive vehicle panels and surfaces.
Boomy - Usually refers to excessive bass response, or peak in the bass response of a recording, playback, or sound reinforcement system.
Bottom End - Also known as Bass response, refers to the sound qualities of the lowest frequency ranges of a speaker or audio system.
Box Rise - The sum of the subwoofer(s) impedance and the additional acoustic impedance added by the enclosure and the vehicle.
Brain - Also known as the Control Unit, the common term used to refer to the main control unit of a security system.
Bridge-tied Load (BTL) - Is an output wiring configuration for amplifiers, a form of impedance bridging also known as bridged transformerless and bridged mono. The two channels of a stereo amplifier are fed from a common signal path, with one channel’s polarity reversed, often in used with subwoofers. This may double the voltage swing at the load as compared to using the same amplifier without BTL.
Bridging - Bridging combines left and right channels of an amplifier into a single, more powerful L+R mono channel. Bridging is common when using a multi-channel amplifier for a subwoofer application.
Brilliance - The range of audio frequencies between 6 kHz and 20 kHz that when boosted, can increase the sense of air and is responsible for sparkle, its composed entirely of harmonics.
Business Ethics - The study of proper business policies and practices regarding potentially controversial issues such as corporate governance, insider trading, bribery, discrimination, corporate social responsibility and fiduciary responsibilities.
Butterworth Filter - A filter with a pass-band with no ripple but usually sacrifices some steepness in attenuation.
Butyl - Is a synthetic rubber, copolymer of isobutylene with isoprene, produced by polymerization of about 98% of isobutylene with about 2% of isoprene. Butyl rubber has excellent impermeability, and the long polyisobutylene segments of its polymer chains give it great flex properties. This is typically used in driver excursion surrounds, sound deadening materials, and some sealants and caulks.
Buying Group - Consortium of businesses that buys in large quantities at discount prices.
Byte - Eight bits. It takes one byte to represent one letter of the alphabet.