"Glenn Gould usually hummed while he played, and his recording engineers varied in how successfully they were able to exclude his voice from recordings. Gould claimed that his singing was subconscious and increased proportionately with the inability of the piano in question to realize the music as he intended.
Gould was renowned for his
peculiar body movements while playing, (circular swaying, conducting, or
grasping at the air as if to reach for notes as he did in the taping of
Beethoven's Tempest Sonata) and for his insistence on absolute control
over every aspect of his playing environment.
The temperature of the recording studio had to be exactly regulated. He invariably insisted that it be extremely warm. According to Friedrich, the air conditioning engineer had to work just as hard as the recording engineers. The piano had to be set at a certain height and would be raised on wooden blocks if necessary. A small rug would sometimes be required for his feet underneath the piano. He had to sit fourteen inches above the floor and would only play concerts while sitting on the old chair his father had made. He continued to use this chair even when the seat was completely worn through. His chair is so closely identified with him that it is shown in a place of honor in a glass case at the National Library of Canada."
Gould lived a private life. Yehudi Menuhin said of him, "No supreme pianist has ever given of his heart and mind so overwhelmingly while showing himself so sparingly."