Zinc is being used only rarely for organ pipes, since high quality material has not been available. The slightly harder metal makes manual processing of the pipes more complicated for the voicer. Nevertheless zinc is much more cost-efficient. Grillo Werke (Germany) has developed a “soft zinc strip” which is significantly better, as far as workability is concerned, than materials available in the past. This material has been tested to determine to what extent zinc modifies pipe wall vibrations, and how essential the impact of the material would be on the sound. Various pairs of pipes made of plain metal and of zinc have been voiced for the same sound, if possible, according to subjective assessment. The experiments prove that the wall vibration spectra of flue pipes made of various materials clearly show differences. Total velocity spectra recorded by means of 3D scanning Doppler laser vibrometry vary considerably. The results of analyzing the stationary sound spectra and the attack transient, however, allow the voicing of these pipes to the same sound. Recording by a microphone array system also proved that the wall vibration does not have any direct influence on the sound radiation of the pipe.