The timbre of musical instruments is principally controlled by the balance and tuning of their sounding modes. In brass instruments like the trumpet, french horn and trombone, the geometry of the instrument is the principal factor determining the mode frequencies. OSCILOS_brass provides an easy-to-use platform for determining the resonant modes of a given bore geometry. OSCILOS_brass is based on OSCILOS_long, the open-source combustion instability low-order simulator (longditudinal), an open source code for simulating combustion instability. It is written in MATLAB, is highly modular, and is straightforward to run and edit. It represents an instrument bore as a sequence of connected cylindrical finite elements. The acoustic waves are modeled as 1-D plane waves. A variety of inlet and exit acoustic boundary conditions are available, including open, closed, Levine-Schwinger and user-defined boundary conditions. The mean flow is calculated simply by assuming 1-D flow conditions, with changes only across element interfaces. This current version is for longitudinal modes only.
For guidelines on contributing and reporting issues see CONTRIBUTING.md.
OSCILOS is freely available under an open source license.