Experiments Connected with End Corrections for Organ Pipes

Abstract

This study was carried out with rectangular wooden pipes in which the fundamental natural frequency was found by resonance. In most cases the pipes employed were not organ pipes. The pipe to be examined was excited by a telephone receiver set into one side of the pipe, and the sound was picked up through a small bore brass listening tube screwed into another side of the pipe and connected by rubber tubing to the observer's ear. The telephone receiver was fed from an audiofrequency oscillator, the frequency of which was varied to obtain the maximum resonant response. The resonant frequency was examined (a) with plates extending at different angles from one edge of one end of the pipe, (b) with one end of the pipe closed except for slits of different sizes, (c) with one end closed except for a slit of chosen width at different distances from an edge of one end, (d) with circular holes of different sizes near the middle of one wall of the pipe. In addition the fundamental natural frequency of each of a number of organ pipes from several organ builders was compared with the frequency obtained by blowing the pipe.