Octave

A musical interval between two tones formed when the ratio between the frequencies of the tone is 2:1.

OEL

Organic Electro Luminescent displays were introduced to the world by Pioneer in 1999, and headunits have never looked the same since.OEL displays, featured in select Premier and Pioneer models, have some intensely great advantages over normal displays namely :

Ohm

Electrical resistance equal to the resistance of a circuit in which an electromotive force of one volt maintains a current of one ampere.

Ohms Law

The basic relationship between current, voltage, and resistance. Ohm's law states that voltage = current x resistance, current = voltage/resistance, and resistance = voltage/current.

Omnidirectional

Literally, from all directions. In audio, microphones are said to be omnidirectional if they can detect sound with equal sensitivity from all directions. Speakers are omnidirectional if they produce sound pressure level that is the same without regard to the position of the listener vis a vis the axis of the driver or port; this tends to be the case with subwoofers and low frequency drivers. Low frequencies, in general, tend to be omni-directional, unlike high frequencies, where directionality increases with frequency.

Open

To pull apart, referring to contacts in a relay or switch. When the circuit is opened, the contacts are no longer touching, and no current flows.

Open Circuit

A circuit containing a switch, filament, voice coil, etc., which is not intact and current cannot flow through.

OSHA

Occupational Safety and Health Administration - The government agency which regulates workplace safety and health.

Output-Audio

The high level (speaker) or line level (RCA) signals sent from one system component to another, or the high level signal from an amplifier to the system speakers.

Output Stage

The final section of amplification before the speaker terminal

Oversampling

A digital filter which calculates additional samples between those taken from the disc, providing a closer representation the original analog signal and therefore better sound quality.

Overtones

Overtones are sounds produced by an instrument (or sound source) that are higher in frequency than the fundamental frequency. They may or may not coincide with the frequencies of a harmonic series (harmonics), although they usually do. Harmonics are always musically related to a fundamental in that they are integer multiples of it. Overtones of a sound are often identical to its harmonics except the first overtone is considered the second harmonic because the first harmonic is the fundamental. Overtones are also sometimes called partials.