The 2015 Huddersfield Contemporary Music Festival (or hcmf//, a vital acronym for Twitter users) began not with a bang, but with an anti-fanfare of dense pianissimo sliding microtones, buzzy with multiphonics. The scene was thus set (by Klangforum Wien performing Substantie by Peter Jakober) for an intense opening evening of three performances that between them encapsulated some of the musical themes, trends and ideas set to play out across the ten days and 30 events to come at Britain's leading contemporary music festival.