Geophone (musical instrument) Geophone (musical instrument) The geophone is a percussion instrument, invented by the French composer Olivier Messiaen for use in his large composition for piano and orchestra entitled "Des canyons aux étoiles…" ("From the canyons to the stars…"). It consists of a drum filled with thousands of small lead pellets, and is played by swirling it around slowly so that the noise of the pellets resembles the sound of dry shifting earth. Messiaen commissioned a Parisian instrument maker to construct one to his design, and he carried this instrument worldwide to early performances of the piece (which was given its first
Recorder (musical instrument) In recorders, like in all woodwind instruments, the air column inside the instrument behaves like a vibrating string, to use a musical analogy, and has multiple modes of vibration. These waves produced inside the instrument are not longitudinal waves, like those the ear perceives as sound, but rather stationary standing waves consisting of areas of high pressure and low pressure inside the tube, called nodes. The perceived pitch is the lowest, and typically loudest, mode of vibration in the air column. The other pitches are "harmonics", or "overtones". Players typically describe recorder pitches by the number of nodes in the