Audio Visual Design Guidelines


10 views November 19, 2019 November 19, 2019 aetm 0


Term Definition
Decibel (dB) The decibel is a relative unit of measurement used widely in acoustics. It is a logarithmic unit describing the ratio between a measured level and a reference value. 

One common ratio to AV people is Sound Pressure Level (SPL). 

Weightings are applied to sound pressure scales to reflect the performance of the human ear under certain conditions. Most typically encountered are:

  • A-weighting: Covers the range 20Hz-20kHz at lower sound levels
  • C-weighting: Used for high level measurements
Acoustic Consultant Professional with specialist skills and experience in acoustics, usually commissioned to advise on the physical acoustics within a space/building and the noise and vibration issues associated with the construction process. 
Designer/AV Designer The professional or technical specialist with responsibility for designing the electronic and electroacoustic (PA) systems and coordinating with other members of the design team. May be employed by the organisation or an external consultant. 

AV designer may also have responsibility for leading electroacoustic scope, where briefed.

Intelligibility Speech intelligibility is a rating of how comprehensible speech is in a given environment.
Mix-Minus An electro-acoustic system that is zoned and routed in such a way to allow microphones from one user to be routed to the speakers of other users for local voice lift functionality
Reverberation Time (RT60) The reverberation time of an enclosure, for a sound of a given frequency or frequency band, is the time that would be required for the reverberantly decaying sound pressure level in the enclosure to decrease by 60 decibels
Signal to noise ratio The difference between the measured sound level and the noise floor (all other sources). Expressed in dB
STI The Speech Transmission Index (STI) is an objective metric ranging between 0 and 1 representing the transmission quality of speech with respect to intelligibility by a speech transmission channel

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