ARTSIM - Acoustic Real- Time Simulation Package A European Collaboration based on the Open Source Concept ADSLib – Acoustic Duct Simulation LibraryASPack – Acoustic Simulation Package ARTSPAC – Acoustic Real-Time Simulation Package EMAS – European Musical Acoustics Simulation Library EADS.Lib – European Acoustic Duct Simulation Library ADSS – Acoustic Duct Simulation Software

Goal of the project Simulation package for arbitrary topologies of acoustical ducts with realistic termination conditions.

Applications Computer Optimization of Wind Instruments Computer Optimization of Wind Instruments Interactive Design of Wind Instruments Interactive Design of Wind Instruments Accurate Modeling of arbitrary topologies (e.g. ventilation duct systems, exhaust systems) Accurate Modeling of arbitrary topologies (e.g. ventilation duct systems, exhaust systems) Bore reconstruction Bore reconstruction Surface condition related loss reconstruction Surface condition related loss reconstruction Determination of true termination impedance Determination of true termination impedance

Final Stage Single Mode, Multi Mode, 2D+3D CFD Single Mode, Multi Mode, 2D+3D CFD Frequency Domain, Time Domain Frequency Domain, Time Domain Basic building blocks Basic building blocks straight and bent tubes and cones straight and bent tubes and cones various kinds of side holes, bells various kinds of side holes, bells various realistic (measured) termination conditions various realistic (measured) termination conditions loss coefficients related to certain surface conditions loss coefficients related to certain surface conditions Easy interactive I/O, numerical & semi-graphical Easy interactive I/O, numerical & semi-graphical

Primary Concepts Efficiency – never calculate something twice Efficiency – never calculate something twice Flexibility – allow any shape with shunt impedances (tone holes) Flexibility – allow any shape with shunt impedances (tone holes) Extendibility – add new models at any time without invalidating application software Extendibility – add new models at any time without invalidating application software Generality – don’t restrict future models in any way, allow mixed mode simulation Generality – don’t restrict future models in any way, allow mixed mode simulation Portability – generate code from abstract descriptions, don’t rely on specific compiler/OS Portability – generate code from abstract descriptions, don’t rely on specific compiler/OS Team Development – strict interfaces Team Development – strict interfaces

Efficiency Hierarchical representation with pre-calculated propagation matrices of whole sections which are rarely modified. Hierarchical representation with pre-calculated propagation matrices of whole sections which are rarely modified. Impedance cache for each section to avoid recalculation in case of constant upstream conditions. Impedance cache for each section to avoid recalculation in case of constant upstream conditions. Notification mechanism invalidates only those cache entries which are affected by the change of a geometric or acoustical property value. Notification mechanism invalidates only those cache entries which are affected by the change of a geometric or acoustical property value.

Example: Pressing a key Input Impedance known by CFD (e.g. Lattice-Boltzmann) Z Bell Z Open Key up/down switches termination conditions Z Term = const ! Z Up A 1 A 2 Z In A 3

Example: Pressing a key Input Impedance known by CFD (e.g. Lattice-Boltzmann) Z Bell Z Open Key up/down switches termination conditions Z Term = const ! Z Down A 1 A 2 Z In A 3

Extendibility, Generality Object oriented approach (inheritance of functionality, partial overload, new properties) Object oriented approach (inheritance of functionality, partial overload, new properties) Generic application interface Generic application interface Enumeration of model capabilities Enumeration of model capabilities Model communicates its properties by name, type and description Model communicates its properties by name, type and description Application can register any property for subsequent modifications Application can register any property for subsequent modifications Generic model and wave datatypes Generic model and wave datatypes

Portability ANSI C++ ANSI C++ No OS dependent libraries No OS dependent libraries Generic graphical output Generic graphical output Simple application interface compatible with VB, C++, Java, Delphi… Simple application interface compatible with VB, C++, Java, Delphi… Open Source policy allows everybody to create its own applications from tested and proven technologies. Open Source policy allows everybody to create its own applications from tested and proven technologies.

Team Development UML Design UML Design Abstract description of class dependencies enforces interface discipline Abstract description of class dependencies enforces interface discipline Documentation already on abstract level Documentation already on abstract level Skeleton code generation for C++ includes all comments Skeleton code generation for C++ includes all comments Version control system Version control system

UML Representation

0,0mm Real-Time Simulation

0,2mm Real-Time Simulation