If you already own the splendid DVD The Unity Sessions you may not rush to acquire what is essentially the audio version of that filmed performance. But it is an extraordinary set and, of course, with no visuals it lends itself to a different listening experience.

Supergroups rarely gel, but there's a remarkable lack of ego in these recordings. Potter and Metheny have very different voices, but each liberates the other – Metheny is more vulnerable, more searching, Potter epically expressive, barely at times able to control himself: and somehow that formidable rhythm section holds these tyros together.

The sheer variety of the sound worlds created here, whether it's those splendid open chords of Metheny's acoustic on ‘Two Folk Songs’ or the curious voicings of the Orchestrion, or the tight doubling of Potter and Metheny on the opening to ‘Police People’, each cut has its own energy and vision. Throw in the colourings Garmassi offers and it's hard not be overwhelmed by the sheer energy of the project.