The instrument’s popularity did not last far beyond the 18th century. Some claim this was due to strange rumors that using the instrument caused both musicians and their listeners to go mad. It is a matter of conjecture how pervasive that belief was; all the commonly cited examples of this rumor are German, if not confined to Vienna.

One example of fear from playing the glass harmonica was noted by a German musicologist Friedrich Rochlitz in the Allgemeine Musikalische Zeitung:

“The harmonica excessively stimulates the nerves, plunges the player into a nagging depression and hence into a dark and melancholy mood that is apt method for slow self-annihilation. If you are suffering from any nervous disorder, you should not play it; if you are not yet ill you should not play it; if you are feeling melancholy you should not play it.”^[14]

The somewhat disorienting quality of the ethereal sound is due in part to the way that humans perceive and locate ranges of sounds. Above 4,000 Hertz we primarily use the volume of the sound to differentiate between each ear (left and right) and thus triangulate, or locate, the source. Below 1,000 Hertz we use the ‘phase differences’ of sound waves arriving at our ears to identify left and right for location. The predominant timbre of the armonica is in the range of 1,000–4,000 hertz, which coincides with the sound range where the brain is ‘not quite sure’ and thus we have difficulty locating it in space (where it comes from), and referencing the source of the sound (the materials and techniques used to produce it).^[18]

LISTEN XX:

http://upload.wikimedia.org/wikipedia/commons/5/51/Stars-GlassArmonica.ogg