Sound

The installation of a sound system in a venue must meet a number of requirements, including acoustic, electroacoustic, perceptual and aesthetic aspects. The various sections of the specifications to be examined in priority are :

a) the sound quality of the reproduction chain: this quality is largely determined by the "high-fidelity" performance of the retransmission chain. It necessarily includes consideration of the signal-to-noise ratio, respect for timbre, absence of distortion and control of feedback and coupling. If necessary, it must offer the possibility of introducing special effects: stereophonic, panning, filtering, phase shifting, delays, etc. ;

b) sound quality at listening points, which involves the study of two families of criteria:

• definition :

  • clarity, intelligibility and articulation for speech ;

  • clarity, transparency and precision of attack for music ;

• spectral balance and respect for timbre in both the direct and reverberant fields;

c) uniformity of overall sound level distribution on stage and in the hall throughout the dynamic range;

d) respect for the balance of sources at all points in the room: this balance includes the relative sound levels of each source as well as their spectral distribution (timbre, color and apparent pitch);

e) coherent localization, i.e. coincidence between "visual" and "auditory" positions of sources;

f) spatial impression adaptable to the nature of the work;

g) the search for optimum clarity on stage;

h) the search for minimum cost, involving :

• a good distribution of investments in room treatment, number of sources and their quality;

• an appropriate adjustment of the electroacoustic powers involved.