Analysis of information sources in references of the Wikipedia article "Vertical viola" in English language version.
Vertical viola. A variation on the viola designed by Carleen Hutchins as part of the new violin family. The vertical viola is 2.5 inches longer than a standard viola and is held vertically to be played like a cello. Also called an alto violin...
Carleen Hutchins, the American physicist and violin maker, has designed a viola whose principal body resonances are in the same relative positions as those of the violin, but even this instrument has a body length of 510 mm, rather long to hold on the arm.
As to the Bartok Concerto, Ma's decision to use a vertical viola, or alto violin (a large viola fitted with a long endpin and held like a cello) stems from his apparent dissatisfaction with the registral displacement: of the authorized cello version (recorded by Janos Starker on RCA, 3/92).
