tremulant

Through the use of a tremulant or two pipes tuned slightly apart this stop produced a slightly undulating tone — an indication that some sort of oscillation was expected in singing.

Organ: The widespread impression amongst a section of the musical public that a unit organ consists of about a dozen vox humanas and a powerful tremulant is based upon observation of the performances of the injudicious.

Several days afterwards I went to the church for the special purpose of experiment; I seated myself at the organ and commenced to improvise on the swell organ with flute, viol d'amour, and tremulant stops out.

Regina, open the organ, and play something soft and holy, with the Tremulant.

She stood by the bench, one hand resting on it; she stood all in the tremulant shadow.