Patricia Racette (Heliane) and Michael Hendrick (The Stranger) are speaking on BBC Radio 3's In Tune about the opera in a few minutes' time.
While waiting, have a look at this article about Patricia.
Dress-ish rehearsal sounded a million dollars in the RFH. And yet more percussion arrived: this time two metal sheets suspended from stands, lurking backstage ready to make whatever noise they make when thumped. I have the impression that the Heliane instruments breed overnight while everyone's away.
