I am very saddened by this news, as I've known and admired Jack ever since his first visit to the Bourges festival in the 1970s when his piece Musik Dari Jalan was awarded a first, later to be followed by two others in his Indonesian triptych. From today's perspective, the "breath of fresh (southern hemisphere?) air" that this piece brought to electroacoustic music then, with its exquisite combination of soundscape recordings (involving street musicians, as implied by the title) and processed versions of those sounds, with seductive transitions between them, set an example for what has evolved into soundscape composition with cross-cultural references. He later published a CD where examples of his field recordings were integrated into his composed works equally seamlessly, a CD entitled Music of the Open Air, as I recall.
I'm aware that he also realized many other instrumental, live performance and collaborative works, unfortunately not well known outside the region, which perhaps others can describe. Here I will just add that Jack was also an early (and rather lonely at the time) pioneering voice for discussing gender and sexuality issues in electroacoustic music, long before my Organised Sound 8(3) article in 2003 which was inspired by him. He even taught a course dealing with that topic early on. And, fairly recently, his innovative work, Intimate Stories, one of which features reminiscences of his partner growing up in Indonesia, was issued on a Bourges CD, yet another example of his courage to push boundaries and make an alternative voice heard.
I trust that his colleagues in New Zealand (and elsewhere) will attempt to ensure that his work and memory are kept alive. His was a unique and powerful voice that deserves to continue to be heard.
Barry