IASCA - International Auto Sound Challenge Association

I.C.E. (In Car Experts) - A national buying group comprised of elite independent mobile electronic retailers.ICE only allows one retailer in a given area. If you are an ICE retailer you are part of an exclusive group of the best independent mobile electronic retailers in America.

Image Rejection - Sometimes a radio station can be picked up at more than on spot on the tuner dial (Ghosting). Image Rejection (expressed in decibels) is a process that filters out every radio signal but the appropriate one.

Imaging - Imaging describes the ability of an audio system to reproduce the directional cues that enable the listener to locate the instruments and vocalists as they were positioned during recording and mixing. Good imaging creates a soundstage that seems natural and lifelike.

Impedance - Measured in ohms. The opposition to the flow of alternating current (AC) in a circuit.

Inductance (or electric inductance) - The measure (in Henries) of the amount of magnetic flux produced for a given electric current .

Inductive Coupling - Radiated noise that is transmitted through a magnetic field to nearby signal paths. This frequently occurs where power and signal cables are in too close of proximity. This is a frequent source of noise and interference.

Inductor - Rated in Henries. Also referred to as coils. A transformer or an electrical component in which impedance increases as the frequency of the AC decreases. Commonly used in lowpass passive crossovers.

Infinite Baffle - A baffle between two areas that prevents waveforms generated out of the front of a speaker from interacting with waveforms produced out the back. Also refers to a sealed enclosure where the internal volume is greater than the Vas of the driver. For more enclosure types see Woofer Enclosure Designs.

Input Sensitivity Control - Also called a Gain Control. Adjusts the amount of input signal being fed to the amplifier stage, not to be mistaken for a volume control which regulates the output signal of an amp. If the Input Sensitivity is set too high, it may add distortion (hiss) to the input signal.

Insertion Loss - The loss of voltage (a ratio measured in dB) caused by a network (like a passive crossover) or component placed between a power source (amp) and its load impedance (speaker).

Insulation (or Insulator) - A non-conductive protective covering for electrically active parts and wire that prevents short circuits and other unwanted interference.

Interface - A device or protocol which facilitates the linking of any two devices or systems.

Intermodulation Distortion - Distortion that results when one set of frequencies is affected by another to produce a third frequency not present in the original signal of either set.

Isobaric - An enclosure loading design in which two or more woofers are coupled together by a sealed air mass to operate as a single driver. Done correctly, impressive results can be obtained from an unusually small box. The downside is that it does require at least twice the amplifier power as needed for a sealed enclosure to produce the same volume level. For more enclosure types see Woofer Enclosure Designs.

ISO-DIN Mounting - A method of mounting the headunit behind the dash panel with side brackets and employing factory installed trim panels.

Isolation - To electrically or acoustically separate to prevent the spread of noise and prevent unwanted elements produced by internal or external devices to effect the signal.