CATT acoustic

technical details 

Actual version: 8.0f

-Acoustic is a software for room acoustics simulation, that allows prediction in high fidelity.  It allows the simulation of variable surfaces and sound sources.The scattering coefficient can be included which is of great importance for realistic auralisation A specifications of the software is certainly the interface for dynamic loud speaker values, this allowes Line-Arrays simulation (2d2-format). Furthermore it´s specific algorithm creates a fairly realistic auralisation.
The actual version can calculate within the frequency range of 125 Hz to 16 kHz in 8 octave-bands, while a higher resolution is in preperation.

Development & Support

CATT is programmed in Goeteborg (Sweden) by Bengt-Inge Dalenbaeck who also takes care of the support. We had good experience with his support, the everage response takes a couple of hours, for urgent projects, bugfixes and special software extensions were worked on within a day
. In close cooperation with CATT-Acoustic Rahe-Kraft invented new features for loudspeaker simulations. For more information go to   www.catt.se.

Data Entry

Before starting a simulation, the space to be calculate needs to be virtually constructed. We doing that with the 3D Software SketchUp Pro 5 und 6 and the inhouse written
Export Plugin SU2CATT.
The import of EASE and Autocad files are possible. The room models are put up under strikt rules, in order to avoid a later error in the succeeding calculations. For a simple analisis on the reflection behaviour of arrays, templates are already programmed. In the case of a pure qualitive analisis for any kind of project, the creation of an ordinary room model serves for valid predictions.
Open models are also possible as no static parameters of the room´s volume have to be taken into account.

You find a full function demo version of SU2CATT for download here.

Sound Sources

Usually polar data in 10 degree resolution is being processed. This necessary data of most of the big manufactures (Meyer, d&b, L-Acoustics and many more) we have at hand. In addition to this data a dll interface for dynamic data stands by to permits almost any frequency (upto 1/16 octave) an polar (upto 1 degree) resolution. Even Line-Arrays and other specifications can be simulated; At this moment the data of L-Acoustics, Duran Audio and Nexo are at hand.
Up to 260 sound sources that are placed in the model can be simulated. The adjustment of the sources is very simple, so that verifications and modifications can be rapidly achived.

Algorithms

Depending on the desired results CATT-Acoustics uses different algorithms.
In the case of a so called Audience Area Mapping, ordinary Ray-Tracing is being practised. This allows good predictions about sound level pressure distribution and speech intelligibility in a relatively short time. A special option permits an extremly fast prediction about the pure direct sound distribution, so that a sound system design can be developed in almost no time.
Results are presented as coloured plots or diagramms.
A image source - algorithm allows the qualitative analysis of possible reflections and reflection paths. Should rooms be acousticly desinged and modified, this function allows to avoid reflections or even optimising of specific surfaces.
The core piece of the software however, is the so called "Randomized Tail-Corrected Cone Tracing" that combines the advantages of the ordinary methods in one single algorithm that calculates the early reflections and the late statistic reverberation. That´s how complex echograms can be calculated to allow realistic auralization.

Auralization

The auralization module, demonstrates the performance of a sound source at any position of the room. To achieve this, the previoly calculated impulse responses are implemented into the different reciever modules either mono (spherical), stereo (binaural or x/y) , 5-chanel surround or B-format(for Ambisonic). The source combination module allows the combination differnt sources without recalculation.
Individual parameter of the HRTFs (Head Related Transfer Functions) can be included. Any audio file, recorded free from reverberation can be used in the auralisazion.
In addition to to the static auralization, simulated head movements at various speed are possible or even " Morphing", which means interpolation between different positions of the recipient in the room, for virtual acoustic walk abouts.
Naturally the calculated sound files can be calibrated among each other. By an apropriate software even background noise can be added, e.g. a realistc impression of being in a stadium. See for yourself.

Room Acoustic Criteria

Calculable parameters: EDT, SPL, SPL Max, Strength (G-10), RASTI, STISTISpeech Transmission Index…

(click to read more)

, Clarity, LF, LFC, Ts, RT, ab V8.0 IACC, and many more.

Output Format

All mappings are shown in the CATT viewer, which can also be send to the customer. Scaling can also be adjusted at a later time.
A variaty of plots can be handed out. Conversion into Bitmaps or EPS is.
Statistics are exported as text file for continuing work with exel, for instance.
The 3D models can be looked at by the CATT viewer. Virtual walkabouts can be linked up by the walkthrough convolver to the auralization. -Link-
The models of 3 D spaces are exportable to VRLM.


New in the current version v8.0d released Mai 05:
- support for the The Common Loudspeaker file Format CLF , see www.clfgroup.org
- export of geometry to CLF cabinet format (useful for CLF authors)
- balloon plot All option (plots balloons for all bands in one plot-file)
- receiver OVERRIDE option
- negative increments allowed in plane loops
- improved multi-tasking
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Continuative Links:

» Planning - how we work » Auralization - sound examples