In both an instrument and a voice, the range in pitch from lowest to highest possible note is finite, and music has provided terms like bass, tenor and soprano to categorize the various ranges. Countertenor is the uncommonly used term for the male singing voice whose range is quite extreme, from the low tenor notes to the middle notes of the highest soprano voices. Musical compositions specific to this expansive range were not uncommon in pre-Classical eras for an all-boy church choir or a castrato whose pubescent voice change had been arrested. Most modern countertenors employ the singing techniques called falsetto voice to reach the high notes, and chest voice to reach the lowest.
For men, the tenor voice is the most common one to sustain the melody of a piece. The origin of the countertenor was a second voice to provide harmonic unison an octave above the lead tenor, or melodic counterpoint within the same tenor range. With the popular introduction of four-part music, the term came to refer to the vocal part which overlaps the top end of a tenor’s range, also called the alto voice. The countertenor part was most popular in the mid to late 1600s when the Roman Catholic Church prohibited women from singing in churches.
One of the consequences of that era was the need for men who could sing in the soprano range. This part fell to castrati — boys who were castrated prior to adolescence in order to retain the clear, high pitch of their youthful voices. Even after this drastic surgical intervention became morally and legally unacceptable, music continued to be written for the countertenor’s vocal range in mind. In such cases, an operatic role for example might be taken by a soprano woman in a man’s costume. Occasionally, modern vocal compositions are encountered, in part because it has such a dramatic range which showcases a singer’s technical skills.
A male countertenor is roughly the equivalent of a female mezzo-soprano, or perhaps contralto. He may be capable of hitting the A note as high as two octaves above middle C on the standard musical scale. This is physically impossible in the normal, or modal, voice of a normally developed human male. He must constrict his throat’s vocal cords to create a higher pitched, falsetto voice. It is typically characterized by a less dynamic, almost electronic, tonal quality.
Countertenors can usually hit notes lower than an average female contralto, perhaps as low as the E note below middle C. This presents a dynamic assertion that the performing singer is, indeed, a man. If a vocalist is unable to reach the lower notes, he can relax his diaphragm muscles and instead simulate strong air flow with an exaggerated vibrato of his vocal cords in a technique called chest voice. The biggest technical difficulty of a good countertenor is seamlessly and imperceptibly switching from modal voice, to either falsetto or chest voice, as the musical score dictates.