Conversations with Nick Cave @ Usher Hall, Edinburgh, 22 Jun

There is, in spite of his wit and warmth this evening, still something in Nick Cave’s movements reminiscent of a composed predator, deliberating whether or not to strike. Adored and widely respected, his presence – never mind his voice – is enough to instantly enrapture the most cavernous of rooms. Many high profile figures would draw blood to be able to simultaneously intimidate and tenderly engage with a large crowd as he can.

Tonight, Cave is reminded of the regard he is held in by doting questioners and, commendably, risks much of their reverence by allowing himself to be vulnerable in a highly unpredictable environment (one questioner asks his favourite colour, another references the Dunblane tragedy as they discuss the brutality of 1996's Murder Ballads) after finding profound comfort and meaning interacting directly with his fans through The Red Hand Files. Many of his responses have gone viral, thanks to their eloquence and his enthusiasm for fruitful engagement. Cave hasn’t been a drug addict in quite some time, but an instinctive need for a new fix remains dominant in him. All the better for us.

Over the course of three hours, Cave alternates between answering questions (audience members are handed microphones by staff upon request) and taking to the piano when inspiration strikes. New life is breathed into Higgs Boson Blues, Stagger Lee and many other cornerstones of his vast discography – including Palaces of Montezuma from the second Grinderman record – as Cave tackles songs rarely aired without Warren Ellis and company providing thunderous support. Brompton Oratory, Breathless and Love Letter are met with reverent silence then ecstatic applause.

Accompanied only by visibly awestruck ticketholders onstage, Cave embraces his audience (at one point, literally, as a young woman walks onstage after asking him for a hug) with a sensitivity it would be difficult to imagine a mere decade ago. This generosity of spirit coaxes an unfiltered voice from his fans in turn, and as a result, Conversations with Nick Cave is unpredictable to such an extent that those in the upper circle are as likely to leave as stimulated and unnerved as those who Cave once stared down in the front row when The Bad Seeds last stormed the Usher Hall in 2013.

The evening is, Cave initially states, an experiment, and he asks us to turn off our "fucking phones" in order to allow questioners the opportunity to attempt to articulate themselves without fear of ending up humiliated "on social media". Cave acknowledges his increasingly diverse audience while recalling The Bad Seeds’ recent arena tour, in which he would make eye contact with tearful, younger listeners during Girl in Amber, standing side-by-side in the crowd with others who were visibly stifling yawns. The chasms in his audience are laid bare this evening, as each ticketholder (visible to all except when the lights dim for a song) is revealed to have strong opinions of how this unprecedented interaction between icon and fanbase should unfold, which, as can be heard on Lothian Road afterwards, causes some to depart with a glass half-empty.

In moments of catharsis, as many are moved by tearful admissions of how Cave’s words have been a comfort, others can be heard complaining about self-indulgence and timewasting. Some questions receive open scorn. One man in his early 20s becomes a little carried away with grandiose references as he ponders Cave’s relationship with mythology, but arguably doesn’t deserve to be booed and belittled to the extent that he is.

Gigs are often seen as places of great community, and it’s a little sobering to see just how much of this sense of kinship is, on occasion, an illusion perpetuated by darkness and merchandise. The quality varies, naturally, in the questions Cave receives, as microphones are handed to those who perhaps aren’t used to public speaking, and there is a palpable sense of frustration amongst those who would like a greater insight into Cave as an artist, particularly as many people speak over others as if they have something of great importance to get off their chest, only to ask about "airport selfies".

It would be more fruitful in some respects to allow audience members to write down their queries in order to better articulate themselves, and to cut down on unnecessary context. However, the completely unmoderated interaction between Cave and his listeners leads to countless unique moments, and the fruits of the experiment are worth the sacrifice of a more cohesive evening. Cave tells a young girl who has recently overcome an eating disorder that there is great beauty and wisdom to be found on the other side of trauma, and pays tribute to the ghosts of former Bad Seeds members whom he feels onstage with him when he performs with the current line-up: "The Bad Seeds are a family." Stranger Than Kindness is performed after Cave humorously recalls founding member Anita Lane, with whom he was once "very much in love", writing the lyrics as an "evaluation of our sexual relationship, which I ended up having to sing."

Tonight, we learn that Cave was once pissed on during a Glasgow show in 1989 ("I’m still in therapy") and that he aims to establish meaning, rather than a moral, in his work, where "nothing is off-limits". The only person to bring up the recent controversy over his decision to perform in Israel is Cave himself, after he details his struggles to understand the Scottish accent, particularly that of his friend Bobby Gillespie of Primal Scream (who recently called Madonna a "prostitute" for singing in Tel Aviv). "It’s maybe for the best," says Cave, "I don’t understand everything he says." Skeleton Tree closes Cave's bold, beautiful and courageous three-hour solo stint on stage. It isn’t always smooth sailing, but Nick Cave’s latest endeavour is something far greater than perfect: it’s interesting.