On the acoustics of organ reed pipes
Eric Cox, Thomas D. Rossing · The Journal of the Acoustical Society of America · 2001
In most lingual organ pipes, the reed vibrates against a fixed shallot and modulates the flow of air passing through the shallot into the resonator. In an earlier paper [T. D. Rossing, J. Angster, and A. Miklos, paper 2pMU6, 136th meeting, Acoustical Society, 1998] we described distinct regimes of oscillation observed in a Trompette pipe. Using a laser vibrometer, we have now observed similar phenomena in two pipes of quite different design: a Rankett and a Krummhorn. Without the resonator the reed frequency in each pipe varies smoothly with reed length, but the resonator lowers the frequency of the reed and also produces distinct regimes of sound, separated by discontinuities, as the system jumps from one regime to the next one. Changing the wind pressure has a modest effect on sound output but little effect on sounding frequency, within limits.