Hall Electro-Acoustics
Ó Tisseyre & Associés
IDDN FR 001 420 005 00 SP 1999 000 30500
Prediction of the electro acoustic quality of rooms
and halls of any size and purpose

Main functions
Using loudspeakers directivity - Sound coverage mapping
Calculation of the multisource time decay - Calcuation of the intelligibility
Control of the positioning of the sound image

PRESENTATION

Acoustics predicting software developed in the Windows environment by Tisseyre & Associés is the basis for computer models supporting the architectural acoustics design of works and operations carried out by Tisseyre & Associés. The latter guarantees results obtained through its modelling.

Faced with numerous demands from its clients and its partners, Tisseyre & Associés makes its acoustic prediction software available, which has evolved from experience acquired in the course of over twenty-five years of everyday confrontation to concrete acoustic problems. These acoustic predictions are validated for each operation by control measurements on acceptance of works, successfully for over twenty-five years.

The HALL ELECTROACOUSTICS software simulates the electro acoustic behaviour of a hall equipped with its sound system.

Adapted to volumes of any shape, it makes it possible to display and evaluate the electro acoustic quality, and therefore optimise the design of the hall under study.


MAIN FUNCTIONS

I - Geometric modelling

  • Creating the hall volume, taking furniture into account.

  • Displaying the volume; various views, zoom, checking the constitution of the surfaces (automatic verification algorithm).

  • Meshing the surfaces: the user chooses the meshing fineness as a function of the specific acoustic constraints on each surface.

  • Setting the acoustic absorption coefficients on each surface, using a database.

  • Selection of the loudspeakers according to their directivity, using a database.

  • Positioning and orienting loudspeakers.

II - Calculation of echograms and objective parameters

  • Sound pressure levels, reverberation time, EDT, clarity, definition, at any point in the volume, due to the sound system.

  • Calculation of the attenuation of sound with distance and Gmid, due to the sound system.

  • Calculation of the directivity of the intensity due to the electro acoustic sound system received at any point, cumulated or according to time with dynamic display on the computer’s screen.

  • Mapping of the energy level received on any surface due to the sound system.

  • Calculation of the front/back and lateral energy ratios, and of the lateral fraction (LF).

  • Calculation of the delays based on the echogram due to the sound system.

  • Mapping of the intelligibility.

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USING LOUDSPEAKERS DIRECTIVITY

The sound intensity coming from every direction in space and due to reflections and loudspeakers, is calculated at a selected receiving position. It shows the main oncoming directions of the acoustic intensity at this point. The dynamic directivity (evolution of this representation with time), on the other hand, shows the received energy as a function of time while making calculation of the lateral fraction (LF) possible. These functions help in the control of the sound plane.

HP (column)
HP (flare)

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SOUND COVERAGE MAPPING

Using the directivity and orientation of the loudspeakers, the acoustic illumination is calculated. This function allows the control of the homogeneity of the sound level repartition. The sound maps of the main sound system may be superimposed to noise maps due to the overall activity (model Intelligibility).


Model of the head platform hall, Gare de l’Est, Paris

Al Shura, The King’s Assembly room in Riyadh,
coverage due to the general sound system


Head platform hall, Gare de l’Est, Paris

Optimisation of the loudspeakers’ orientation in cinema theatres with their coverage and implantation.

Implantation

Optimal sound coverage

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CALCULATION OF THE MULTISOURCE TIME DECAY


HALL ELECTRO-ACOUSTICS calculates the echogram due to all the loudspeakers. This function provides the reverberation time increase due to the effect of multiple loudspeakers in the hall. This allows setting the delays.


Official Reception Banquet, Riyadh

Official Reception Banquet, Riyad
Echogram due to all the loudspeakers
compared to that of the hall alone

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CALCULATION OF THE INTELLIGIBILITY

The calculation is based on the time shapes and the signal-to-ambient noise ratio. The intelligibility percentages obtained are that measurable by the direct method (see publications).


Model of the head platform hall, Gare de l’Est, Paris


Grand hall – Palais de la Découverte, Paris


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CONTROL OF THE POSITIONING OF THE SOUND IMAGE

The calculation of propagation of the acoustic wave in the room is based on the finite elements (method of meshing). This makes it possible to see the direction and the relative importance of the acoustic reflections: visualisation by the directivity of reception. The calculation is based on the energy sent by the loudspeakers (directivity of emission) and the energies of re-emission of each finite element making the envelope of the room; this yields the static and dynamic (time decomposition) directivities of reception, which shows where the energy, stemming from the loudspeakers, comes from, and makes possible to control the positioning of sound objects.


Directivity of reception in large orchestra configuration.
Reception at the right-hand side of the conductor

Main modelizations carried out to this day
Congress halls : Porte Maillot Paris, Acropolis Nice, Kiev Ukraine, Berlaymont 2000 Belgique, Al Shura Riyadh, Official Reception Banquet Riyadh
Theatres : Neuilly, Périgueux, Toulouse, Nimes, Vincennes, Les Célestins in Lyon.
Halls : Gare de l'Est, Strasbourg tramway, Frankfurt Hilton, Dubai and Singapore airports, Grand Palais in Paris.
Amusement centers : Astérix Paris, Naturascope Loudun, Caldea Andorra.
Cinemas : Megarama Bordeaux, Gaumont (Paris, Toulouse, Montpellier), Pathé, Boulogne sur Seine, Arp in Clichy, Multisalles Beyrouth, cinemas in Cayenne, Nice…

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