without accompaniment

In his letter to Zelter, Beethoven says that one of the numbers of the Mass was without accompaniment.

Miss Amory played beautifully, with extraordinary feeling and execution, both with and without accompaniment on the piano.

There was always sameness of sound, it was always chanted without accompaniment in unison.

It ended with a Lutheran hymn, sung sweetly without accompaniment, by five or six young girls.

He played without accompaniment a little tune that seemed to twitch the heart.