Božič's music was strongly influenced by jazz and a keen sense of musical drama. His early concertos for trumpet, trombone and saxophone and his Sonatas in cool show clearly the jazz influence, and his use of extended tonality and traditional forms. From 1963 he adopted new methods, including a form of serial working and free rhythmic coordination, but with no loss of melodic interest. His frequent use of speakers is well illustrated by the collage tape work Trije dnevi Ane Frank, Polineikes and, above all, Jago, a musico-dramatic characterization derived from Shakespeare. Even in chamber works such as Kriki and Collage sonore, speakers are included in the ensemble. Although Božič made only modest use of electronic sounds, he frequently used collage rather than musique concrete tape techniques, as in the bitterly ironical but magnificent reinterpretation of the funeral rite in his Requiem of 1969.
Works (selective list)
Dramatic: Mali prodajalci, 1957; Baletska jednočinka, 1957; Humoreske, 1958; Spoštovanja vredna vlačuga, 1960; Gluha okna, 1967; Jago, 8 performers, tape, 1967-8; Ares-Eros, 1970; Lizistrata, 1975 Orchestral: Pf Conc., 1956; A Sax Conc., 1958; Humoreska, hn, orch, 1959; Trombone Conc., 1960; Tpt Conc., 1961; Improvizacije, 6 groups, 1963; Sym., 1964-5; Audiografika, cl, trombones, pf, perc, str, 1970; Audiospectrum, 1972; Audiostructurae, pf, orch, 1973 Vocal: Ciganske pesme , cantata, reciter, solo vv, chorus, ens, 1962; Sedmina, 4 reciters, orch, 1966; Šesta pesma iz ciklusa Blaznost , reciter, b cl, tpt, str qnt, 1965; Collage sonore, 2 speakers, cl, tpt, str qnt, 1966; Kriki , speakers, brass qnt, tape, 1966; Polineikes, 5 reciters, orch, tape, 1966; Slovenske pesmi, cantata, 2 speakers, Mez, orch, 1973, rev. 1975 Chamber: Conc. grosso, ens, 1960; Sonata in cool no.1, fl, pf, 1961; Sonata in cool no.2, cl, pf, 1962; 5 Sketches, tpt, pf, db, 1963; Sonata in cool no.3, fl, b cl, harp, 1965; Elongacije, pf, ens, 1967; Polyrhytmia, wind qnt, 1968; Pop art I, pic, str qt, 2 metronomes, watch, 1969; Pop art II, str qt, tape, 1971; 3 D, tpt, hn, trombones, 1972; ABA 72, cl, pf, 1972; Pop art III, str qt, 1973; Audiogem I-IV, str, qt, 1974 Tape: Trije dnevi Ane Frank , reciter,6 insts, elec, all on tape, 1963; Requiem spominu umorjenega vojaka – mojega očeta , 5 reciters, chorus, ens, all on tape, 1969 Principal publishers: Društvo slovenskih skladateljev, Gerig