Interesting, ain't it? In a radically different setting from Purple, his voice became all of the sudden funkier and grittier, he found a way to reinvent himself. He had nothing to do with the instrumental music - that was all the do of the bunch of Weather Report fans that made up IGB -, but the vocal melodies and phrasing above the funk-jazz melee were all his.
I never associated his performance on the three IGB albums with Glenn Hughes, but come to think of it, you're right! Gillan and Hughes have never sung together, but Gillan rates Hughes as one of the strongest British singers, albeit with the predicament of always sounding like someone else, namely Stevie Wonder!
Mind you, IGB was one of the most divisive post-Purple split-off projects. Purple fans were flabbergasted by all the syncopation going on and fusion (a genre quite popular at the time) fans passed at the thought of
that ex-DP screamer from Made In Japan - of all people! - fronting a jazz rock outfit, you weren't really allowed to do that if you weren't immediately identified with a black voice. And when Punk came, that sounded the death knell.
To me the IGB and especially their jazziest second album "Clear Air Turbulence" were one of the best things Ian did outside of his day job. Six lengthy tracks, yet everyone of them amazing.
Mark Nauseef's drumming and especially how he employed the bass drum was and remains incredible.
And I'm not alone in my assessment, this guy here
is a fan of that particular album too.