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Indoor noise prediction

CadnaR is a powerful software program for predicting indoor acoustics. CadnaR enables users to carry out on-site acoustic simulations, making it the ideal tool for noise issues in the workplace and for room acoustics optimization as well. It is based on exactly the same software interface as CadnaA, the noise prediction software for outdoor use.

Features

Main characteristics

  • modeling of rooms with complex geometry
  • modeling of the geometry of noise sources (points, lines, areas, parallelepipeds)
  • definition of noise levels generated by machinery
  • definition of directivity of occasional sources
  • assistance in selecting absorbent products, based on a materials data library
  • specific assessments of the effectiveness of solutions
  • analysis of the impact of alternative solution scenarios, in particular through the calculation of noise level distribution on a mesh, in 2D and 3D modes
  • comparative calculations between scenarios (grid arithmetics)
  • voxel grid: volumetric mesh with projection of levels in the x, y and z planes
  • assessment of acoustics quality criteria (psychoacoustics)

Description of rooms

In simple cases, rooms are modeled using cubic shapes. Rooms with a more complex shape can be defined through the use of screens. The effect of noise control solutions can then be analyzed by applying absorbent materials with various acoustic characteristics, either on entire walls or partial surfaces.

The software makes it easy to model obstacles such as machines, desks and other furniture. These items are taken into account when considering phenomena such as screening, diffraction, reflection, and diffusion.

The absorption level of objects in a room (walls and obstacles) can be selected from a library of absorption coefficients, which is provided as standard. The library contains more than 700 absorption coefficient spectra, according to ISO 354 (in octave or third-octave bands). Users can add to the library if desired.

Calculation methods

The calculation methods offered by CadnaR include:

  • mirror images: using this method, reflections occurring on a room’s surfaces, on obstacles and on reflective noise sources, are modeled using ray diagrams. The trajectory of each ray is plotted individually, taking into account reflections on all types of obstacle, up to the specified reflection magnitude
  • particle model: using the particle model method, a large number of “particles” is transmitted at random in all directions from each noise source in the room. This method takes into account the reflective properties of the obstacles and surfaces in the room, up to the specified reflection magnitude
  • VDI 3760: this method, for which the protocol is defined in the German standard DVI 3760, is based on the method of mirror images. It takes into account the application of diffraction and attenuation, according to Kuttruff and Jovicic
  • diffuse field: this option allows the sound pressure level to be calculated according to Sabine’s statistical theory of reverberation in rooms.

Data import and export

  • data editing in the library (spectral data: sound power level and absorption coefficients)
  • import/export directivity data from occasional sources
  • import coordinates of receiver points
  • import bitmap file to represent the background of the room studied
  • export object geometry and calculation mesh in DXF format
  • extensive printing options (printing protocol, printed report, printed graphics using Plot-Designer).

Applications

  • noise level assessment in workplaces and workshops
  • calculation of noise distribution in lecture halls and conference rooms
  • optimization of acoustics in catering establishments, recreation rooms, game rooms, sports halls, etc.
  • calculation of the benefits of acoustic walls or panels, with different levels of absorption depending on location
  • verification of the compliance of industrial premises with health and safety directives and legislation
  • assessment of parameters describing the quality of room acoustics and other psychoacoustic parameters related to music and / or speech performances
  • planning of different audio setups in multi – purpose halls according to uses (concerts, conferences, etc.) in just one file with different variants.

Audio

The new option “audio” enables the user of CadnaR to determine parameters describing the quality of room acoustics and other psychoacoustic parameters. These room parameters are important, for instance, in the fields of music performances or speech transmission and intelligibility:

  • reverberation time (T30, T20, T10)
  • early decay time (EDT),
  • definition and clarity (D50, C50, C80)
  • speech transmission index (STI, STIPA)
  • articulation loss (Alcons%).

Demo version

Get an idea about the handling of CadnaR!

Results are diverted and the following functions are deactivated at this point in time:

  • option audio (calculation of psychoacoustic parameters)
  • various functionalities of option VIS (visualization)
  • all functions which require saving a file
  • printing
  • export
  • calibration of Bitmaps
  • library manager
  • protocol

To download CadnaR demo version please click here.

Downloads

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2018-12-03T15:11:07+00:00