1337Chapter 35
Computer Aided Sound System
Design
by Dr. Wolfgang Ahnert, Stefan Feistel and Hans-Peter
Tennhardt
Introduction.............................................................................. 1339
35.1 Sound Design Basics for Acoustic Simulation................................................ 1339
35.1.1 Measurement and Planning Methodology with Physical Models of Large Auditoriums............. 1340
35.1.1.1 Fundamentals................................................................... 1340
35.1.1.2 Balance Investigations of Music Performances......................................... 1341
35.1.2 Building a Computer Model, Entering Room Data.......................................... 1342
35.1.3 Acoustic Sources and Loudspeaker Systems.............................................. 1343
35.1.3.1 Natural Sources................................................................. 1343
35.1.3.2 Loudspeaker Types.............................................................. 1344
35.1.3.2.1 Point Sources..................................................................... 1344
35.1.3.3 Loudspeaker Line, Sound Column and Line Arrays with In-Line Arrangement of Radiators..... 1350
35.1.4 Wall Materials...................................................................... 1354
35.1.4.1 Absorber Data.................................................................. 1354
35.1.4.2 Scattering Data................................................................. 1354
35.1.4.3 Diffraction, Low-Frequency Absorption.............................................. 1354
35.1.5 Receivers and Microphone Systems..................................................... 1355
35.1.5.1 Human Ears.................................................................... 1355
35.1.5.2 Microphones................................................................... 1355
35.2 Transducer Data for Acoustic Simulation.................................................... 1356
35.2.1 Simulation of Loudspeakers........................................................... 1356
35.2.1.1 Simulation of Point Sources....................................................... 1357
35.2.1.2 Simulation of Complex Loudspeakers............................................... 1360
35.2.1.2.1 Modeling by Means of a DLL Program Module.......................................... 1360
35.2.1.2.2 Modeling by Means of a GLL Data File................................................ 1362
35.2.1.3 Background of Simulation and Measurement.......................................... 1362
35.2.1.3.1 Resolving the Far-Field Problem...................................................... 1363
35.2.1.3.2 Acquisition and Interpolation of Complex Data.......................................... 1363
35.2.1.3.3 Configurable Loudspeakers.......................................................... 1365
35.2.1.3.4 Shadowing and Ray Tracing......................................................... 1367
35.2.1.3.5 Additional Notes.................................................................. 1367
35.2.2 Receiver Simulation................................................................. 1368
35.2.2.1 Simulation of the Human Head..................................................... 1369
35.2.2.2 Simulation of Microphones........................................................ 1369
35.3 Tools of Simulation..................................................................... 1370