(Ger.: ‘vocal in-building’).
A term used for a device often found in Bach's music (and, less often, in that of his contemporaries) whereby the opening ritornello, or part of it, is repeated during the course of an aria while the singer incorporates new material into it. When the technique is employed in a chorus – as, for example, in bars 98–114 of the opening chorus of Bach's Cantata no.72 – it is usually referred to as ‘Choreinbau’. An analogous procedure is also found in arias and choruses by Classical and pre-Classical composers in which a secondary theme, presented in the tonic as part of the opening ritornello, returns in the dominant or relative key as accompaniment to new material for the singers.