A harmonic is a wave whose frequency bears a whole number relationship to the frequency of a reference signal. Complex sounds, such as the human voice or the sound of a stringed instrument always consist of a fundamental frequency and then a number of harmonics, which, depending on their amplitude, will make up the basic characteristic of that sound.

The result of passing audio through some electronic device. Since it is impossible to make a perfectly linear device (audio out exactly matches audio in) harmonic distortion is always a byproduct of signal processing.

A type of antenna formed by a coiled small-diameter spring, usually covered in plastic and somewhat flexible. Physically shorter than a standard 1/4-wavelength whip antenna, but also considerably less efficient.

High Pass Filter - A filter that attenuates frequencies below a certain cutoff point, while passing on frequencies above the cutoff unaffected. Sometimes referred to as low-cut filter.
(See Filter)

Used in reference to computer based recording systems. In the early days of computer recording, much of the processing work had to be done on additional hardware cards, while the computer merely provided visual feedback.

A type of audio connector often used for the microphone connections on wireless body-pack transmitters. The connector wiring is not standardized within the wireless industry. Also referred to as a Hirose Connector

A type of microphone pick-up pattern. Similar in shape to a cardioid pattern, except that the sides have the greatest amount of rejection, as opposed to a cardioid pattern where the rear of the microphone has the least sensitivity.

Integrated Drive Electronics is a standard electronic interface that is used as a data path for a computer's disc storage devices. IDE drives are cheaper and less expensive to implement when compared with SCSI drives.

A high-speed data exchange protocol, it provides a single plug-and-socket connection on which up to 63 devices can be hung. Additionally, the technology allows for hot-swapping devices, while data transfer allows for speeds of up to 400 Megabits per second. Common on personal computers these days, IEEE 1394 is implemented by Apple as FireWire, and by Sony as iLINK.
(See Firewire)

Abbreviation for input/output. In audio, the term refers to the physical inputs/outputs of a particular piece of equipment. Also used to describe any operation, program or device that transfers data to and from a computer.