Ultrasonic

Having frequencies above the range of human hearing, commonly considered to be 20 kHz. Not to be confused with "supersonic", which means faster than the speed of sound. Ultrasonic frequencies in the signal path can sometimes cause harmonic distortion in audio components that are in the human hearing range and quite audible.

Ultrasonic Sensor

A form of spatial sensor that is designed to detect an intrusion into a vehicle by monitoring the space within the vehicle with ultrasonic energy.

Unfused Wire

Any section of wire between the power supply and a load that does not include the protection of a fuse or circuit breaker.

UniPlane

Flat drive technology utilized by JBL. This technology inverts the cone to permit for shallower mounting depth than conventional drivers.

Unison

In music, unison is used to describe an identity of pitch. When two or more tones are sounding at the same frequency or pitch, they are said to be in unison with one another.

Unity Gain

A device or setting which does not change signal level, neither amplifying nor attenuating the signal, is said to be at "unity gain". Many processors are set up for unity gain; that is, they can be plugged into a system without changing its overall levels. In practice, unity gain is often a desired setting for maintaining gain staging, and for optimizing operating levels and signal to noise ratios.

Universal Interface

A JBL innovation that allows amplifiers and other outboard electronics to operate from any type of input from a factory car stereo. The Universal Interface will create a pre-amp quality signal from high power, standard power, or balanced outputs.

Uni Block

A heat sink technology used by JBL to shield the amplifier circuitry from radiated noise found in most vehicle's electrical systems.

Unloading

The digital subcode information that identifies a disc, indication the number of tracks, the starting and ending points of these tracks and the total running time of the disc. When include, CD Text information is stored in the TOC.