Nine choirs from around the world and many more from around Israel - 750 voices in all - get together starting this Monday for the 21st Zimriya choir convention, continuing through August 9. The almost daily concerts and workshops taking place at Atzmaut Hall at the Mt. Scopus campus of the Hebrew University are all free, starting with the opening concert there Monday night at 9. The choirs from abroad include the Mixed LIRA Choir of Croatia, which sings Jewish-themed songs as well as Croatian folk; the all-girls Ulmer Spatzen youth Choir, singing jazz, pop, folk and Baroque tunes; the 30-member mixed Kinor Ladino Choir from Canada; the mixed 25-member Ensemble Vocal Zamir of France; the 35-man Baruch Brothers Choir of Serbia; the 28 young men of the Saint Stephen of Dechanl of Serbia, singing church music of different epochs, folk, and contemporary; the 50-strong Girls Choir Skowronki from Poland, singing a contemporary, Baroque and Romantic repertoire; and the Soul Boys of Chicago, belting out gospel. On Thursday at 6 p.m. the Kinor Ladino Choir and the Ulmer Spatzen Youth Choir will sing at the Bell Cave in Beit Guvrin in a free concert as part of the Bible Festival.