Imagine you are at a study day being run by Friends of the Earth. They mount a play in which a group of angels who somehow got left out of the Book of Genesis fall to a completely barren earth, look around, and start reconstructing, re-enacting its life and death. They plant, grow, overgrow, eat, overeat; they tell themselves the earth will always be fruitful, but they’re mistaken. In the end two of the angels become Adam and Eve and walk off hand in hand into a ruined landscape lit by the rising sun. Then Luke Bedford sets it all to music.

This week we’ve some pioneering, trailblazing Mahler with a dramatic twist, courtesy of a conductor who mentored Leonard Bernstein. Elsewhere, there are some disconcerting, dark sounds from a youthful German composer, and a supremely entertaining disc of highly theatrical vocal works courtesy of Paul Hillier’s immaculately drilled Theatre of Voices. Turn on, tune in and drop out while listening to Cathy Berberian’s cartoon-inspired Stripsody, and consider the very question of what constitutes music.

In a week in which the nation has debated the relevance of classical music, it was left to the LSO’s Eclectica concert series to have the final word. Incorporating world and electronic music alongside traditional chamber works and contemporary programmes, Eclectica’s concerts offer dressed-down, laid-back forays down the roads less travelled of the classical repertoire. With one of the 20th century’s musical greats as a grandfather and a growing reputation for his work as a producer, DJ and composer, incorporating classical music into a club idiom and setting, who better than Gabriel Prokofiev to weigh in on the debate?

Contemporary music and 11 new productions are at the heart of a strong ENO 2011-12 season announced today.

Sometimes you can leave a concert feeling slightly shortchanged: a perceived weakness in the programming; an unprepared, lacklustre conductor; a phoned-in performance. No danger of any of the above at the marathon session three of Reverberations, a weekend of concerts at LSO St Luke's and the Barbican devoted to the music and influence of the contemporary US composer Steve Reich. Actually, by the end of the evening, some people may have been ruing just how many artists have fallen under Reich's influence. We filed into the Barbican at 6pm on Saturday.

Were the great Diaghilev alive today, surely he’d be working in the imaginative possibilities of electronic technology - this was the opinion given me by the arts panjandrum, the late Sir John Drummond. And given the developments of 3D, who knows? Would it be this manipulation of our perceptions that fascinated him? 3D is certainly everywhere in dance now, though the challenge is to leap the judgment of it as merely a gimmick. I reckon while Wim Wenders’ film Pina 3D achieved that, the version of Stravinsky’s Rite of Spring by Klaus Obermaier doesn’t.

John Cage, the focus of an adventurous three-day mini-festival in Bristol, is possibly one of the most influential figures in 20th-century culture. As much a practical philosopher as a composer of note, he made artists, writers and musicians think about the nature of chance, our place in nature and the role of the subject in the creative process.