introduction manual catt

CATT-Acoustic v8.0 with TUCT -Introduction Manual

1. Introduction 1

2. Installation 2

3. Mini-tutorial 3

Creating a new project and model 4

Map direct 10

Map measures 11

Predict SxR 11

Window | Pixel rendering 14

Window | Surface rendering 14

Window | Image Source Model 15

Window | Time trace 15

Round-up 16

4. Software overview 17

Hardware requirements 17

Hall geometry and absorption 17

Coordinate system 19

Frequency range 20

Source directivity 20

Data output 20

5. A background to CATT and CATT-Acoustic 21

Appendix 1: Demo limitations 23

Appendix 2: Short GEO, LOC input file syntax reminder 24

Common directives in GEO and LOC-files, placed anywhere 24

Geometry-files (.GEO) 25

Coordinate definition tools (for the CORNERS section) 26

Source-file (.LOC) 27

Receiver-file (.LOC) 27

CATT-Acoustic v8.0 with TUCT - Introduction Manual

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Copyright © CATT 2010


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1. Introduction

This manual gives a brief introduction to using for CATT-Acoustic v8 with TUCT for 32-bit Windows (XP or higher) for demo testers and new users. All versions include ahelp-file always covering the full version and purchased licenses also come with PDFand printed manuals.

TUCT will take over all prediction and auralization in CATT-Acoustic but during a tran-sition period the main program will stay essentially as it is to ease the transition for oldusers. Eventually it will be stripped down to handle mainly geometry modeling andchecking, libraries and other support functions and TUCT will perform the actualprediction and auralization, once that transition is complete it will be labeled CATT-Acoustic v9. New users are strongly recommended to use only TUCT for prediction, itis separate program but is considered a part of CATT-Acoustic.

This document contains parts of the help-file adapted for a standalone printeddocument. The contents are installation instructions, a mini-tutorial, a softwareoverview and a background to CATT and CATT-Acoustic.

Document conventions:

CATT-Acoustic v8 or CATT-A v8 indicates the main program CATT32.exe.

CATT-Acoustic or CATT-A indicates the CATT-Acoustic software in generalincluding TUCT.

File-names, folder-names, text to be entered and text-file contents are set inCOURIER like in C:\CATT

Menu selections are set in bold like in File | Preferences

Dialog names are set in italics bold as in General settings.

Dialog items are set in italics as in General settings/Input folder

Dialog groups are set in italics within brackets as in (Edit).

Programs and program modules are written with a colon like in Prediction: orExplorer:

Product, organization and company names are written in italics as in CATT-Acoustic

All products mentioned in this document are trademarks of their respective owners.


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2. Installation

CATT-Acoustic is installed by running a self-extracting installer. No CATT files areinstalled in the windows folder and no system files other than the Registry (for storingPreferences settings and associating file name extensions) are altered.

All CATT programs and other read-only related files are kept in a folder selected atinstallation, typically in a Program files sub-folder. This folder will hereafter be calledthe “CATT folder”.

All CATT data-libraries, and the DLL Directivity Interface are kept in a separate folder.This folder will hereafter be called the "CATTDATA-folder" and "CATTDATA-folderANECHOIC" means the ANECHOIC sub-folder. This folder is at initial installationsuggested to be:

XP : C:\Documents and Settings\[user]\Application Data\CATT *)

Vista, Win7 :C:\Users\[user]\AppData\Roaming\CATT *)

Where [user] is a place-holder for the logged on user.

If more than one logged-on user will be using the software, and want to share thelibrary data, it can be more practical to install in

XP: C:\Documents and Settings\All Users\Application Data\CATT *)

Vista, Win7 :C:\ProgramData\CATT *)

*) or corresponding name on a non-English Windows

The CATTDATA folder can be moved or copied to another location with read/writerights and the new location be selected in File | Preferences. It can also be placed ona network drive assuming that the network path has been mapped to a drive letter (e.g.Z:)

In the CATTDATA folder are placed sub-folders with library files and sample models:

⋅ ABSLIBS with surface properties library-files (*.DAT), which library to use isselected in CATT-A v8 File | Preferences;

⋅ SD with source directivity files (*.SD0, *.SD1, *.SD2, *.CF1, *.CF2);

⋅ SD2DATA with DLL Directivity Interface (DDI) modules and data;


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⋅ HRTFS with Head Related Transfer Function libraries;

⋅ HEADPHONES with headphone equalization filters;

⋅ ANECHOIC with anechoically recorded music and speech (and for full versionsome program material filters);

⋅ MODELS with sub-folders DEMO, EXAMPLE and TUTORIAL containing roommodels and prediction settings-files for the shoebox in this Introduction manualand for the help-file section 2 example and section 11 tutorial.

⋅ Other files such as the hidden option text-file (not used with the demo version)

Each logged on user can have his own personal CATTDATA and settings as managedby CATT-A v8 File | Preferences.

After installation, the files and folders that should be present can be seen in the help-file section 1.1.

3. Mini-tutorial

Below are shown typical steps predicting the acoustics of a simple shoebox-shapedhall with one source and one receiver to give you a feeling of what it is all about. Thisexample is a "mini-tutorial" and is kept as clean as possible avoiding most of the moreadvanced features that are used in the Example hall in the help-file Section 2.3 and inthe dedicated Tutorial in Section 11. In addition to direct use of the flexible scriptinglanguage in the GEO-format, models can be created via an AutoCAD AutoLISPinterface (not included in demo version, see help-file section 10), via DXF import (seeFile | External CATT Tool | DXF2GEO) or via 3rd party SketchUp tools (seewww.catt.se/pred_mod.htm for available plugins). The procedure here uses onlythe GEO-format since even with a CAD export basic knowledge of the GEO options isessential.

Start CATT-Acoustic v8. The Prediction module window opens updirectly, note that TUCT only is checked so that only controls usedwith TUCT are enabled initially. The Plot-file viewer module is alsoopen and fills a large portion of the frame window

CATT-Acoustic v8 and TUCT are Multiple Document Interface (MDI)applications so that the menu-bar items may change when a differentmodule is activated. A list of available and open modules can befound on the Window menu and in CATT-A v8 all open modules areshown as toolbar icons (to the right of the standard New, Open andSave icons).


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Creating a new project and model

Create a new project by selecting Utilities | Create a NewProject. The appearing dialog expects you to select a folder forthe hall you are going to work with (sayC:\HALLS\THEATER1). The Browse folder button in the dialogalso allows you to create a new folder (if a non-existing folder is specified it will becreated).

When you click OK, all basic files are created automatically, ready to be used.

MASTER.GEO template master geometry-fileREC.LOC receiver positions (a generic position inserted)SRC.LOC source positions and data (a generic source inserted)GEO.PRD prediction settings-file prepared for geometry checkPROJECT.TXT a text-file for optional notes about the project

Select (Edit)Geo-file and MASTER.GEO and CATT-Edit loads with the file.

CATT-Edit is a separate application but communicates with the main program so thatfiles can only be edited in one instance of the editor, and if a file needed for predictionhas been changed but not saved, you will be prompted before the file is read.

We will now enter a simple shoebox shape structured as in Fig. 1.

A0

01

1

2

3

4

11

12

13

14

Fig. 1: Simple shoebox model for the mini-tutorial

Enter the geometry data as shown below (the files can also be found in theCATTDATA sub-folder MODELS\SHOEBOX). Data items in the geometry-file areconstants, surface properties and various other declarations, corner ids andcoordinates (x, y, z) and, finally, plane definitions. Comments are introduced by a


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semicolon ";" and blank lines are allowed. See help-file section 2.3 for full details andin this manual’s Appendix for a short syntax description.

;MASTER.GEO;constant declarationsLOCAL h = 8 ;hall height in mLOCAL w = 10 ;hall widthGLOBAL d = 24 ;hall depth

;absorption and scattering coefficients 125Hz to 4kHz [%], optional RGB-colorABS audience = <40 50 60 70 80 80> L <30 40 50 60 70 80> { 255 0 0 }ABS wood = <15 13 10 9 8 7> L <30 30 30 30 30 30> { 255 255 0 };Notes:;- if 8k and 16k values are known they can be given after; a colon as in <15 13 10 9 8 7 : 7 8 > otherwise they; are extrapolated from 2k and 4k values.;- RGB-color is optional, one will be auto generated if not given.;- scattering coefficients are optional (but strongly recommended); if not given the default values in General settings will be used

CORNERS;floor corners 1 -w/2 0 0 2 -w/2 d 0 3 w/2 d 0 4 w/2 0 0;ceiling corners11 -w/2 0 h12 -w/2 d h13 w/2 d h14 w/2 0 h

PLANES[1 floor / 4 3 2 1 / audience ][2 ceiling / 11 12 13 14 / wood ][3 stage wall / 1 11 14 4 / wood ][4 rear wall / 3 13 12 2 / wood ][5 left wall / 2 12 11 1 / wood ][6 right wall / 4 14 13 3 / wood ]

99999 planes can be used numbered from 1 to 99999 in any order. In addition to thebasics shown above the GEO-format offers e.g. automatic mirroring of symmetricalgeometries, interactive constant input, mathematical expressions, accurate surfacecreation tools, object rotation and copying, loops and many other tools, see help-fileSection 2.3.

The surface property data can either be entered directly in a geometry-file, as with theABS directive above, or already be defined in the library managed by the Surfaceproperties module, see help-file Section 3.

Save MASTER.GEO.

Select (Edit) Receiver-file and REC.LOC and enter the receiver data (one receiver perline, in any order): receiver ids and the corresponding positions (x, y, z).


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;REC.LOCRECEIVERS 1 -3 d-4 1.3

Note that global constants defined in a GEO-file, in this case d, can be used in source-and receiver-files. 100 receivers can be used numbered from 0 to 99.

Save REC.LOC.

Select (Edit) Source-file and SRC.LOC and enter the source data, each sourceoccupies a number of lines. Source data items are source ids, source positions (x, y,z), source directivities, source aim points (x, y, z) or as a function aim(H,V) specifyinghorizontal and vertical aiming angles, SPL values for the six octave-bands at 1 mdistance from the acoustic center on the axis. Optionally source roll angles, 8k and 16k1 m SPL values can be given, see Help. This simple example uses the pre-definednatural omni-directional source OMNI and if an electro-acoustic source, such as aloudspeaker is used, the source syntax is slightly more complex adding a Lp1m_ea orGain_a line and a Delay_e line, see help-file section 2.3 (CATT-Edit has a Templatemen to insert common constructs).

;SRC.LOCLOCAL src_z = 1.7SOURCEDEFS;id --pos x y z-- directivity -- aim point (has no effect with omni) -- A0 1.0 1.7 src_z OMNI 1.0 3.7 src_z Lp1m_a = <70 73 76 79 82 95> ; SPL at 1m on the source axis 125 Hz to 4 kHz

260 sources can be used numbered A0, A1, A2, … , B0, B1, … Z8, Z9. Sourcedirectivities are handled in the Directivity module, see help-file Section 4. Note how alocal constant, src_z, is used to ensure that the source is aimed in the horizontalplane (takes no effect in this case since the source is omni-directional).

Save SRC.LOC.

The Create a New Project utility also created a basic prediction settings-file GEO.PRDautomatically loaded when the project was created. Select General settings andbrowse through the various items. In the geometry file specific scattering coefficientswere given but for surfaces with no given coefficients the Surface default will be used.Diffuse reflection can affect the results very significantly, see help-file Calculationrecommendations (section 2.5).

Bauphysik

Hervorheben

Bauphysik

Hervorheben


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Click OK and select Geometry view/check and browse through the various items. ClickOK and check the created geometry by clicking Save and Run on the main dialog thatwill create basic geometry plot-files and a plot-file list.

The current settings-file is also saved so the next time you run it will contain the samesettings. Settings-files can be used later on for sequence (batch) processing, see help-file Section 8 (CATT-A v8 prediction only). If an input-file has been edited and changedwithout having been saved afterwards, the editor containing the file is moved to thefront and a prompt is displayed asking if the file should be saved before continuing(unless you have made a change by mistake, the answer should be Yes).

The Prediction module reads the created geometry-file, source- and receiver-files inthe project folder (i.e. the Input folder in the General settings dialog) and creates filesin the Output folder. Typically, each test case for a project should be directed to a newOutput folder created as a sub-folder to the Input folder. One created file, namedPLT_GEO.TXT, contains all created geometry plot-file names and the Plot-file viewermodule uses it to automatically show files created (when predictions are made the list-file will be called e.g. PLT_GEO_FULL.TXT if both a geo check and a Full detailedcalculation is made, CATT-A v8 prediction only).

Such plot-file lists can be reloaded after calculation and also be customized with theview module or a text editor to show an assembly of results for presentations also withauto-playing WAV-files attached to plots.

The VIEW4.PLT file is shown in Fig. 2. Next/Previous file can be selected on the Plot-file control floating dialog, from the toolbar or by pressing the PgDn/PgUp keys. Thegraphics can be printed out, copy/pasted into other applications or exported in variousformats. For 3D plot-files, the mouse can be click-dragged directly in the window torotate the model or the camera and for 2D formats clicking in the window zooms to theclicked fourth. The View module is described in the help-file Section 5.

Instead of using actual foldernames, “.” can be used as ashortcut for the folder where thesettings-file (.PRD) is located,typically the project Input folder.The folder entries can then simplybe e.g.:

Input folder : .Output folder : .\OUT

This is especially useful if a projectis moved to another location.


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5m

Y

Z

X

Y

X

Z

A0

01

Audience:240m² Volume:1921m³ (approx.)

Fig. 2: Sample 2D plot-file VIEW4.PLT

Pay special attention to the PLINFO.PLT plot-file shown in Fig. 3 where each planeand plane sub-division is a sub-frame, it also indicates in which GEO-file the plane isdefined in and on which line.

125 500 2k 8k

100%

50%

0%

A0

01

3

13

12

2

Plane 4 : rear wall, S=80,00m²

MASTER:36

WOOD .......... <15 13 10 9 8 7 : 6 5> L <30 30 30 30 30 30 : 30 30>

Fig. 3: PLINFO.PLT 3D plot-file for model checking

Next/Previous frame can be selected on the Plot-file control (or the toolbar, or by click-dragging on the yellow window title, or by left and right arrow keys if the control dialogis closed). By pressing F a frame can be selected by the left mouse button, pressing Fagain allows rotation of the model, via Options | Select Frame a list of all planes willbe shown. All planes can be stepped through and should have the front (reflecting)side colored and the back black. If they do not, the plane corner entering order has tobe reversed. This can either be done by reversing the sequence of corner ids or bysimply changing / to \ in the plane definition concerned. Plane corners have to beentered either as seen clockwise from the backside or from the front side of a surfacebut the entering order has to be consistent. The default is clockwise from the backside(i.e. from the non-reflecting side of a surface typically as seen the from outside of theroom). If the reverse order is preferred the directive FROMFRONT must be inserted atthe top of the GEO-file (before CORNERS).

The file COLORED.PLT is a colored 3D representation and the file SHADED.PLT is ashaded 3D representation of the model where surfaces are shaded in an angle-


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dependent manner if the reflecting side is visible. This makes it simple to spot e.g.holes or reversed surfaces in the model and complements the PLINFO.PLT file forchecking the model.

In addition to the PLT-files a file called SHADED.OGL was created in the output folder.This file is used by the OpenGL-based stand-alone CATT 3D-viewer and has manyviewing options, lighting, viewpoints etc. The viewer is documented by its own help-fileand is simple to use.

If the geometry needs to be adjusted edit the geometry-file MASTER.GEO again by(Edit) Geo-file and repeat Save and Run.

For a bit of experimenting change the line

LOCAL h = 8 ;hall height in m

in MASTER.GEO to

GETLOCAL h = 8 ;hall height in m

and you will be able to enter the height at a screen prompt while the file is being readafter Save and Run has been clicked (GETLOCAL has further options for checking, seehelp).

Let us assume that the geometry now looks OK. It is then time for some predictions ofthe acoustics. CATT-A v8 offers many prediction tools but in “TUCT-only mode” onlyone, Interactive RT estimate, is available since it is often applied in an early stage of aproject, it gives classical Sabine and Eyring estimates and material statistics andoptionally can perform a fast global T-30 estimation using ray-tracing. For moredetailed predictions and auralization TUCT is used and will be exemplified with theshoebox model.

First select in CATT-A v8 (TUCT) Audience area mapping… and select the plane id ofthe audience plane (enter 1 in only the first or in both edit boxes and press the Addbutton, leave the Map step and Map height as they are for this test) and OK, then click(TUCT) Save CAG and Run and a file will be created in the output folder with thename taken from the General settings Project and with an extension .CAG and TUCTwill be run (each time a new file is created using the same project name it willincrement a number added to the name). TUCT has its own help-file and manual witha more thorough introduction so only the basics will be covered here.

TUCT offers three main prediction methods asselected via the Main:Actions dialog:

Predict SxR: full detailed echograms and impulse responses, using basic to advancedprediction algorithms that all can directly be used for auralization and parameterestimation.


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Map direct sound: color mapping of direct sound and source delays over selectedaudience planes.

Map measures: color mapping of parameters over selected audience planes –mapping uses a slightly modified version of algorithm 1 in Predict SxR;

TUCT also offer several tools that can be used independently ofthe main methods as selected via the Window menu:

Pixel renderingSurface renderingImage Source ModelTime trace

Let us do a quick tests of the above.

Map direct

Click Map direct (on the Main:Actions window) and click Run (notmany options necessary for just direct sound and one source)and the direct sound over the audience area will be shown in theMain:Show 3D window, see Fig 4.

Fig. 4: Sample direct sound mapping

Use the (Audience mapping) Max and Range +/- to select a suitable scale but for anomni source it is not a very exciting display. This function should not use a very smallmap step since it has to be compatible with Map measures that typically has a 0.5 to 1m map step, the Window menu offers more detailed direct sound Pixel and Surfacerendering.


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Map measures

Click Map measures (on the Main:Actions window) and checkAuto select for both No of rays/cones and (Echogram) Length,and then click Run and after some processing time roomacoustics an sound system measures over the audience areawill be shown in the Main:Show 3D window, see Fig 5 for anexample with C-80.

Demo note: the actual number of rays used will be limited.

Fig. 5: Sample mapping of C80

Use the (Audience mapping) Max and Range +/- to select a suitable scale and(Audience mapping) Type to select one of the many measures. Some measures likeSTI pops up dialogs with additional options. Note that in an artificial non-mixing roomlike this more rays are required to give a less random variation from map point to mappoint.

Predict SxR

Click Predict SxR (on the Main:Actions window) and check Autofor both No of rays and (Echogram) Length, and then click Runand after some processing time echogram and impulseresponse results are available in the Main:Show 2D window foranalysis and direct convolving/playing. The following figures willshow a few examples of the results created. Note the two curvesshown for most cases, that are from using pressure additiongiving an impulse response (blue) and energy addition giving anenergy echogram (red) and the differences at low frequenciesindicates the uncertainty, for more details see TUCT help “2.TUCT algorithms”


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Demo note: the actual number of rays used will be limited.

Fig. 6: One of many room acoustic Measures, here C-80

Fig. 7: One of many Echogram-like displays, here theSchröder curves with EDT and T-30 line regressionsshown.

Fig. 8: One of many Impulse response based displays,here a binaural IR. For more IR details see Window |Main: Impulse Response Detail


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Fig. 9: A very special Impulse response based displayusing a rotating microphone including the patent-pendingSector micTM. Note the direction of the microphone as inMain:Show 3D window.

Auralization

As soon as a Predict SxR calculation is finished direct IR playing and convolving isavailable via Play/Convolve. In File | Preferences a number of Alias for anechoicWAV-files or filters can be selected and can be selected for convolution, also HRTFsand headphone eq can be selected. The controls below Play/Convolve allows for WAVcreation (not in limited versions) and relative calibration. Holding down Ctrl whileclicking Play/Convolve will play the anechoic WAV.

Demo and Prediction license note: for playing only one anechoic WAV can be used,binaural IRs using simplified HRTFS and Headphone eq and in the demo the IR issomewhat truncated before convolving (the demo allows too few rays to give goodauralization of the late part), for more information see TUCT help “4.1 Licenselimitations”.


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Window | Pixel rendering

Displays SPL color maps on all visible model surfaces and/or visible audiencesurfaces of either incident or directly reflected sound.

Fig. 10: Pixel rendering of direct sound (all visible pixels)

Window | Surface rendering

Similar to pixel rendering but renders all surfaces at a selected absolute resolutionallowing rotation of the model and rescaling results without a recalculation;

Fig. 11: Surface rendering of direct sound, model can befreely rotated.


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Window | Image Source Model

Detailed early specular reflections for qualitative reflection path studies.

Fig. 12: Image Source Model results, many displayoptions and mouse selection of reflections.

Window | Time trace

A wavefront-like specular ray display that can be stepped through in time.

Fig. 13: Time trace, display options such as coloringafter order or sound level.


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Round-up

These were the basic steps running CATT-Acoustic v8 with TUCT in its most genericforms. The help-file example in Section 2 and the Tutorial in Section 11 give morerealistic model examples. Note that the Tutorial can first be run through directly in thehelp-file since many of the plots created are included and illustrates also multiplesource addition, binaural post-processing and auralization (using CATT-A v8 functionsnot required with TUCT).

For the first project it might not seem worth while to use the advanced possibilities ofcreating a structured geometry and use named constants and expressions to definecorner/node coordinates etc. This is certainly true if one gets everything correct thefirst time and if the hall design never has to be changed or fine-tuned. Most projects,however, require a lot of fine-tuning of the design. Often some of these changes canbe anticipated and be allowed for by using named constants (e.g. reflector heights orangles). The extra time spent planning in the first part of the project will almostcertainly pay off in the later part. If only numbers are used it is very easy to paintoneself into a corner and it is also very difficult to understand the model construction afew weeks after it was created or if it was created by someone else.


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4. Software overview

CATT-Acoustic is a room acoustic prediction program that includes many predictionmethods and tools. Each methods has its special benefits and drawbacks and can beselected depending on case.

Hardware requirements

CATT-Acoustic requires an IBM PC compatible equipped with a Pentium processor orhigher and Windows XP or higher.

Hall geometry and absorption

The hall geometry can have any reasonable shape as long as it can be approximatedby a maximum of 99999 planes (plane surfaces). This limit is arbitrary and can beincreased in the future, if required, but generally better results are not created by avery detailed model, rather the opposite.

As the geometry input is made by using a text editor, the input-file format has beenmade very forgiving allowing for blank lines and comments and no need to place thedata in fixed columns.

Powerful facilities such as symbolic constants, expressions (even with calls to mathfunctions), IF-statements, tracing statements, interactive input, and hierarchicfiles for the geometry are incorporated. Rather then just read by the main program thegeometry-files are interpreted.

Overview of the geometry description:

· number of corners/nodes in the model (in practice) only limited by availablememory

· hierarchic geometry-file organization enabling structuring of the geometry (usingthe INCLUDE directive):

main hallbalconiesreflectors

extra reflectorsaudience

· geometry-files can be scaled e.g. to compensate for erroneous drawings or toconvert from imperial to metric units (the SCALE directive)


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· a geometry-file can be defined as an object and then be translated and/orrotated (typically for reflectors) and also be made to duplicate its contents with anew set of translation/rotation values (the OBJECT, ROTATE, TRANSLATE andCOPY directives)

· mirroring of symmetrical (or nearly symmetrical) halls (the MIRROR directive)

· symbolic constants and expressions with calls to math functions can be used tospecify coordinates, translations, rotations and several other values (the GLOBAL,GETGLOBAL, LOCAL and GETLOCAL directives + SIN, COS, TAN, ARCTAN, SQRT,EXP, LOG functions)

· functions are provided for creating model corners that are automatically locked toplanes, and for creating corners as intersections between lines and planes(lock() and cut() functions), and a loop() function.

· tools are provided for maintaining a structured model, such as declaring e.g. thex-value of a corner to be the same as the x-value of another corner, or the use oflocal corner and plane numbers in each file (x(), y(), and z() functions).

· planes can be sub-divided in any number of sub-planes each with differentabsorbing/ diffusing properties. By dividing a plane consisting of several differentabsorbing/diffusing parts into sub-divisions instead of making one plane definitionfor each part, the calculation time will decrease and the model easier to interpret.

· planes and plane sub-divisions can be concave (i.e. have re-entrant angles) orconvex with number of corners and number of sub-divisions (in practice) onlylimited by available memory

· plane corners can either be entered ordered clockwise as seen from the back sideor from the front side of reflecting planes (user choice but must be consistent ineach GEO-file; FROMFRONT and FROMBACK directives).

· libraries of named absorbing/diffusing surface properties. Number of entriesonly limited by available memory.

· absorbing/diffusing properties can be specified in several ways:

· as a named library entry (very common materials as entered in the Surfaceproperties module)

· as a named entry in a geometry-file (common materials in a certain hall, theABS directive)

· directly in % (not so common materials that perhaps need no names)


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· a plane or a plane sub-division can be assigned an automatic frequencydependent edge diffusion to emulate the diffusing effects of diffraction

· a frequency dependent semi transparency can be specified.

· a frequency dependent default diffusion can be specified.

· marker elements or loaded marker-files for non-acoustical visual elements.

Coordinate system

In principle any right-handed coordinate system could have been used, but to usemirroring of symmetrical parts and for view angles for perspective plots, aiming anglesfor a source, reflection incidence angles and head-direction Stage to be understood,the system has to be as follows, see Fig. 7.

z

y

y

x

stage

side view

top view

Fig. 7 Hall coordinate system

Imagine standing on the stage of the hall looking towards the audience:

· The x-axis should run from left to right

· The y-axis should run towards the audience

· The z-axis should run upwards.

The origin can be placed anywhere but it is recommended to place it along a hallsymmetry line (to utilize the mirror function), at the stage wall, the stage front, or at theproscenium. If the hall has no typical stage, model the longest hall dimension as ysince many plots are optimized for a longer y dimension.

SI units are used but since the input data-files can use scale-factors for thecoordinates of the hall model, it is possible to enter everything in any decimal unit. The


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output, however, always uses SI units. With the AutoCAD interface (not included in thedemo bt can be requested) or DXF2GEO (see File | External CATT Tools) alsoimperial units can be used. Decimal numbers transferred to the CATT GEO-file formatwill be the same as inside AutoCAD since scale-factors are used to convert to meterwhen the files are read. In addition to these tools 3rd party SketchUp plugins areavailable.

Frequency range

All calculations are, or can be, made for eight octave-bands: 125 to 16k Hz.

Where it is relevant calculation is also made for the power sum of these six or eightoctave-bands and A-weighted.

If no data is available for 8k and 16k Hz extrapolation is made based on the values at2k and 4k Hz.

Note: the underlying theory is geometrical acoustics and in most halls thelowest two octaves will not be well predicted. For small rooms such ascontrol rooms and studios typically only the upper octaves 1, 2, and 4k Hzwill be well predicted (8k and 16k Hz may suffer from lack of proper inputdata) but qualitative analysis is useful also for the lower octaves. TheInteractive RT estimate dialog gives an estimate of a reasonable frequencyrange for a given room.

Source directivity

Source directivity is handled by the Directivity module and patterns are modeled eitherby entering or importing horizontal and vertical polar values for every 15°, by importingmeasured data in a 10° full space format, the CLF (www.clfgroup.org) or via theDirectivity DLL Interface (DDI) e.g. for array modeling. Text import/export.

Data output

Data output can be requested for any combination of up to 260 sources (A0 to Z9)and up to 100 receivers (00 to 99) and any combination of octave-bands plus thepower sum of the octaves where relevant.


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5. A background to CATT and CATT-Acoustic

A short presentation of me - Bengt-Inge Dalenbäck, the program developer - and thecompany CATT.

I acquired an M.Sc. in electrical engineering 1980 with a thesis in semiconductortechnology, working on a gas sensitive Field Effect Transistor (FET).

I have been involved in acoustics since 1981, the years up to 1989-90 mostly as apart-time teacher at Applied Acoustics, Chalmers University of Technology,Gothenburg, Sweden.

1986 I started an independent company CATT (Computer Aided Theatre Technique)originally developing theater lighting and decor design CAD software and was until1996 half-time occupied at the department and half-time at the company. Since 1988CATT has concentrated on software for room acoustics.

1990, I joined the Chalmers Room Acoustics Group for half-time Ph.D. studies. Seethe CATT www page for a list of publications.

1995, December, I received a Ph.D. on room acoustic prediction and auralization atChalmers.

A list of main programming projects within CATT:

· 1987, CATT-Lighting: 3D CAD-program for theater lighting design (built on ray-tracing).

· 1987, CATT-Decor: 3D CAD-program for decor design on theater stages aimed tosupport CATT-Lighting. With an object library and with hidden line removal.

· 1988, CATT-Acoustic: Room acoustic simulation using the image source model.

The first three projects were implemented on a Commodore Amiga.

· 1989, CATT-Acoustic MS-DOS. The lighting and decor design programs aredropped and the work concentrates on room acoustics and PC-software.

· 1990, Binaural post-processing of the results from CATT-Acoustic creating binauralimpulse responses to use for audible simulations (so-called auralization). Forconvolution a Lake FDP-1 convolution processor was required.

· 1990-1994, Various enhancements and upgrades of CATT-Acoustic.

· 1994, Software convolution enabling auralization using only a PC sound-card.Specialized hardware is now optional.


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· 1996, June, release of CATT-Acoustic v6 for Windows 3.1.

· 1996, July, goes from a 50% to a 10% position at Chalmers fully concentrating onCATT.

· 1996, August, release of CATT-VRoom designed for full frequency-range studio andvirtual reality reverb together with a Lake DSP Huron or CP4 convolution processor.

· 1997, March, release of CATT-Acoustic v6.1 for Windows 3.1.

· 1998, February, release of v7.0 for 32-bit Windows introducing the RTC.

· 1998, October, v7.1 introducing the DLL Directivity Interface (DDI) and arraymodeling.

· 1999, October, v7.2 introducing RTC-II and the OpenGL-based CATT 3D-Viewer.

· 2000, The FIReverb Suite, for natural music FIR reverb and multi-channelconvolution (CATT-VRoom is enhanced, renamed to PureVerb and supplementedby the MultiVolver).

· 2001, The FIReverb Suite 2nd Ed., 24- and 32-bit processing, Ambisonic decoder.

· 2002, February, CATT-Acoustic v8.0 with 8k and 16k Hz processing, materialcolors, visual markers, walkthrough convolution, 5-channel post-processing.

· 2005, CATT-WalkerTM for real time walkthrough auralization.

· 2000-2008, continuous enhancements of v8 and extensive work on the CLF project(www.clfgroup.org)

⋅ 2010, March, release of TUCT that will replace all prediction and auralization inCATT-Acoustic

CATT can be reached at:

CATTMariagatan 16ASE-41471 GothenburgSWEDENPhone/fax: +46 31 145154e-mail: [email protected]: http://www.catt.se

For an up to date list of CATT-Acoustic distributors, see the CATT www home page orcontact CATT directly.


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Appendix 1: Demo limitations

General demo limitations:

⋅ AutoCAD interface files are not included, but the documentation can be seen inthe help-file Section 10 and the files can be provided after request (the DXFconverter is included, see CATT-A v8 File | External CATT Tools)

⋅ certified loudspeaker data (such as the CLF format or protected SD0 or SD1)cannot be used (CLF can be viewed but not used in prediction).

⋅ The DLL Directivity Interface for array modeling cannot be used (theCATT_Generic ARRAY0 model can be used with max two elements)

General demo limitations in TUCT are mainly:

⋅ the number of rays is limited in Predict SxR and Map measures.

⋅ The Image Source Model max 3 orders.

⋅ Time trace max 3 orders and 5000 rays.

⋅ Playing/convolving only of single source, binaural IRs with sphere HRTFs, ageneric headphone eq, and a fixed anechoic WAV-file;

⋅ The auralization in TUCT has other types of limitations but are also based onthe sphere HRTFs and the generic filter.

⋅ Playing/Convolving is limited to use IRs around 25% of the predictedreverberation time, for a realistic late reverb more rays than allowed in the demoversion have to be used.

⋅ no IR, Walker or HeadScape export.

Nevertheless, the demo enables a thorough evaluation of CATT-Acoustic includingTUCT and any models created can be used with the full version.

CATT-A v8 has similar demo limitations not listed here since as indicated theprediction and auralization parts will be phased out to be handled only by TUCT.


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Appendix 2: Short GEO, LOC input file syntax reminder

Common directives in GEO and LOC-files, placed anywhere

IF expr1 condition expr2 THEN (condition: <, <=, =, >= , > ,#)statements

ELSE (optional)statements

ENDIF

IF expr THEN (IFs cannot be nested)statements

ELSE (optional)statements

ENDIF

SAY message displays message on the screen and waits for OK to be pressed.

SAY constant displays the constant value and waits for OK to be pressed.

RETURN forces end-of-file (can be used for debugging purposes).

BREAK message forces abort of the processing with message shown on screen.

Comments are introduced by a semicolon (;) blank lines are allowed.


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Geometry-files (.GEO)

INCLUDE filename (multiple, #I short form, includes after file)SCALE sc_x sc_y sc_zOBJECT TRANSLATE t_x t_y t_z (SHIFT alternative form) ROTATE r_x r_y r_z ORIGIN o_x o_y o_z (seldom used)OFFSETPL numberOFFSETCO numberFROMFRONT|FROMBACK (FROMBACK default)MIRROR co+ pl+ [EXCLUDE pl_id ...]COPY co+ pl+ o_x o_y o_z t_x t_y t_z r_x r_y r_z (mult., #C short form)GLOBAL name = expr | string (multiple, #G short form)LOCAL name = expr | string (multiple, #L short form)GETGLOBAL name = expr | string [options] (multiple)GETLOCAL name = expr | string [options] (multiple)ABS absname = <α125 ... α4k : α8k α16k >

ABS absname = < α125 ... α4k : α8k α16k > L <s125 ... s4k : S8k s16k>

ABS absname = < α125 ... α4k : α8k α16k > L < estimate(size) >

ABS absname1 = absname2ABS absname1 = absname2 L <s125 ... s4k : s8k s16k>

(all ABS variants multiple, values in % (unless ABS1 is used), values in italics areoptional)

For details and some further less often used directives and how to apply semi-transparency in ABS, see help-file.


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CORNERSc_id c_x c_y c_z... (more corners, can also use loops, see below)

PLANES[ pl_id pl_name / c ... / abs ]or a sub-divided plane[ pl_id pl_name / c ... / ( sub_name / c ... / abs ) ... ]... (more planes, can also use loops, see help-file)

MARKERS (optional section for non-acoustical visual elements, see help-file)...

(markers of type POLY, LINE, DASH, RULE, CIRC, DISC, TEXT and LOAD)

Coordinate definition tools (for the CORNERS section)

lock(id1 id2 id3) locks the x, y, or z-value to the plane definedby corners id1, id2 and id3.

cut(lid1 lid2 pid1 pid2 pid3) calculates a coordinate as the intersection ofthe line lid1 to lid2 and the plane definedby pid1, pid2 and pid3.

x(id), y(id), z(id) returns the x, y, or z-value of corner with id.

loop(id_start,i,i_start,i_stop,i_step,x_expr,y_expr,z_expr)see help-file

expressions: cos(), sin() etc. see help-file


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Source-file (.LOC)

SCALE sc_x sc_y sc_zLOCAL name = expr | string (multiple, #L short form)GETLOCAL name = expr | string [options] (multiple)

SOURCEDEFS (items in italics are optional)s_id s_x s_y s_z srcname a_x a_y a_z rollLp1m_a = <L125 ... L4k : L8k L16k >... (more sources, for electro-acoustical sources and many options see help-file)

Receiver-file (.LOC)

SCALE sc_x sc_y sc_zGLOBAL name = expr (multiple, #G short form)LOCAL name = expr (multiple, #L short form)GETGLOBAL name = expr|string [options] (multiple)GETLOCAL name = expr|string [options] (multiple)

RECEIVERSr_id r_x r_y r_z [h_x h_y h_z] (h_… optional individual head direction)... (more receivers)

Receivers can also be created by loop functions: recloop(),recloop2() andrecwalk(), see help-file.

introduction manual catt

Documents

plid plname

dll directivity

coordinate

file viewer

main program

general settings

abs

view module