Musical effects of the digital pressure-controlled valve
Tamara Smyth, Jonathan S. Abel, Julius O. Smith · The Journal of the Acoustical Society of America · 2004
In computer music, a digital simulation of the pressure-controlled valve is required to model many wind instruments and vocal systems. The method used for simulating the valve usually depends on how closely it corresponds to any of three simple configurations for valves in acoustic tubes. The classification of the valve is determined by whether an additional upstream or downstream pressure causes the valve to open or close further on the corresponding side. In this work, a configurable model of a pressure controlled valve is implemented, allowing the user to design a valve simply by changing the model parameters. The user may design three simple models: one that is blown closed (like woodwinds or reed-pipes), one that is blown open (as in simple lip-reeds, the human larynx, harmonicas and harmoniums) and the transverse model (as in the bird’s vocal organ, the syrinx). Using the computer model, the musical applications of different valve configurations and topologies (where valves are arranged in series and in parallel) will be examined. For several cases, observations will be made on how the valve couples differently with the tube-resonator and how this affects the produced sound.