Johns steps up to the mic and starts singing a capella, before stopping to request a different microphone as the current one sounds "a bit boxy".
"I can remember many years ago I was playing keyboards for Silverchair, and he'd be hearing the tiniest little things, like pianos out of tune microtonally," he says.
At the end of May there will be two full-length shows at the Sydney Opera House for the Vivid Festival, the success of which will determine whether Johns does any more gigs in support of .
(He initially planned to do none.) Dressed in a loose-fitting, moth-eaten singlet, his black jeans hiked up above his calf-hugging black boots, the first thing you notice is how healthy he appears: lean, tanned even, with a shock of sandy-blonde hair that looks like it's been styled not to look styled.
His girlfriend of three years, Estelita Huijer, got a tattoo of a tiger at the same time, a shared ritual to mark the moment when Johns started work on his solo debut in earnest.
"That was the turning point after years of experimenting, so let's do something to mark the occasion." Rewind a month, and he and his seven-piece band have gathered at a studio in Sydney's inner-west to rehearse for the debut performance of his solo material, at the APRA Awards in Sydney on March 24th.
"He's a sucker for the details." He is also, since the release of his debut solo single, "Aerial Love", in January, back in the spotlight for the first time since Silverchair completed touring in support of 2007's .