(category) – Technical

Sound Pressure Levels Our ears respond to fluctuations in the steady atmospheric pressure, so when measuring sound, that is what we usually measure. Sound pressure levels (or Sound Levels for short) are specified in Decibels, relative to a reference pressure of 20 micropascals. This reference pressure of 20 micropascals is nominally equal to the threshold…

Talkback originated in radio studios, where staff in the control cubicle who could hear the presenters and performers on their monitor loudspeaker were able to communicate with them using a dedicated microphone/loudspeaker system, “talking back” to the studio. This system was extended by the introduction of “reverse talkback” which provided the presenter with an additional…

Stereo, short for Stereophonic, is a system of sound recording and reproduction which uses two synchronised channels, usually referred to as A (left) and B (right). There are several conventions for colour-coding analogue signals; the BBC adopted the nautical convention of Red for Port (Left) and Green for Starboard (Right), which can be confusing when…

Panpot is an abbreviation of Panoramic Potentiometer, a device used in Stereo mixers to vary the signal levels sent to the outputs from a Mono input, and thus apparently move the sound across the “sound stage” between left and right.

The human ear does not react to changes in sound in a simple, linear way. To double the loudness of a sound, say by turning up the volume control on an audio amplifier, most people find that they need to increase the power produced by the loudspeaker by about ten times. If we were to…

Pressure Zone Microphone is a registered trade mark of Crown International, and describes a method of mounting a microphone close to a flat surface to minimise room acoustics. Other variants are described as Boundary Microphones. See http://www.uneeda-audio.com/pzm/

An Interference Tube is simply a long metal tube with a series of circumferential slots cut into it, fitted onto a directional Microphone. These slots produce interference patterns in sound waves from the sides, resulting in partial cancellation of off-axis sounds and a resultant apparent increase in the gain of sounds from directly in front.

Broadcast Wave Format was developed by an EBU Project Group (see The Broadcast Wave Format – an Introduction) to provide a product-independent means of exchanging programme material between workstations from different manufacturers. It is based on the Microsoft WAVE audio file format (file extension .wav), which is one of a number of file types specified…

Super Audio CD (SACD) launched by Sony in 1999 and intended to supersede the original Sony/Philips CD.

Direct Stream Digital (DSD) uses a sampling rate of 2.8224 MHz to directly record a 1-bit signal. Used for recording SACD, launched by Sony in 1999.