Computer analysis of the effects of valve actions on initial transients in organ flue pipes
Norman Kinnaugh, George R. Plitnik · The Journal of the Acoustical Society of America · 1979
Computer measurements have been made of the onset transients of a set of experimental “Principal” organ pipes. The pipes were played individually from a number of valves closely resembling the two most common types of pipe organ valve actions. One action (representative of many electro-pneumatic types) has a small circular valve directly beneath the pipe; the other action (tracker type) consists of a long rectangular valve which admits air into a chamber which feeds the pipe. The analysis was a time-tracking correlation of the fundamental frequency from the time of valve opening through to the steady state. Partials were treated as a quasiharmonic series and analyzed similarly. Steady-state spectra of the same pipe played on different valve actions shows results which are contrary to that reported by some previous researchers. (The pipes and experimental wind chest were donated by the M. P. Moller Co., Hagerstown, MD.)