There has been no shortage of Brad Mehldau albums in recent times – the solo Live in Marciac, Highway Rider with his trio plus Joshua Redman and a chamber orchestra, in a quartet with Pat Metheny, with soprano Renee Fleming and so on. Here is his latest album, a collaboration with fellow pianist Kevin Hays and composer arranger Patrick Zimmerli. Featuring pieces by each of the three musicians plus works by Steve Reich, Ornette Coleman and Philip Glass, Zimmerli’s arrangements for two pianos are replete with “technical challenges” which must have been similar to solving a vast acrostic, so evince admiration at overcoming the technical obstacles, but little to warm the emotions.