It's been exactly 30 years this summer since Sinead O'Connor's first record - the In Tua Nua single Take My Hand - came out so it feels fitting, with her 10th studio album, I'm not Bossy, I'm the Boss, about to be released that we're sitting in the very studio where that debut was recorded.

The intervening years could surely fill 10 volumes of autobiography but, tattoos aside, she sits before me looking largely unscathed by the years. Those same unmistakably large brown eyes still gleam with a mixture of sincerity and mischief and her figure is back to its lithe self. The latex-clad vamp of the recent photo shoots is nowhere to be seen - "most people know that it's ET they're going to meet" she laughs - and she seems happy and relaxed. She's returned to this studio intermittently over the years - 1994's Universal Mother was recorded here too - and it's a place where she feels comfortable "going into the dark and making an absolute show of myself, squawking like a demented cat".

That freedom to make mistakes is important, because, as she explains, in music, as in life, you have to get a lot wrong to get it right. "Artists are strange kinds of people," she tells me. "We don't do embarrassment. The difference between being an artist and being an entertainer is that being an artist translates into the rest of your life. An artist is the same off the stage."

These are words she has lived by. More than any other Irish artist she seems to live with her emotional tendrils exposed to the world, her filter switched defiantly to 'off' mode. She's sometimes been mocked for her social media excesses, but she's always seemed bigger than the controversy du jour and latterly has matured into something of a national treasure. A mural depicting her in Temple Bar reads: 'Sorry Sinead you were right all along, we were wrong.' ("I'm surprised nobody's slashed it yet", she laughs). In the days before we meet, Arcade Fire tear up a picture of the Miley Cyrus - a reference to both Sinead's spat with the pop starlet and the Irish singer's shredding of a picture of the Pope - and 'The Boy In the Striped Pyjamas' author John Boyne pens a gushing love letter of a piece about her in The Irish Times. She was mildly disappointed to learn that Boyne is gay ("a writer is the perfect boyfriend", she once told me "they have lots of time to snuggle and a desk to bend you over") but he spoke for a lot of people in the rapture of the piece. Even the Miley furore underlined the fact that a generation of younger artists have grown up revering her. Another fan, and sometime collaborator, American singer songwriter John Grant, recently described her as "an inspiration…someone who was herself when the whole world was screaming at her to be something else."

She performed with Grant several times over the past few years and was with him in April while putting the finishing touches to the new album and suffering the fallout from a brief tryst - "the one that got away" she calls him - and the stomach-dropping agony of persistent kidney stones, which would later require two emergency surgeries. Somehow she managed to pull herself onto the stage and their performance of Glacier, with Conor O'Brien of The Villagers, was one of the concert highlights of the year so far. "I underwent lithotripsy", she explains, "which are these enormous machines invented by the Nazis to dissolve people (and were used to try to get rid of the stones). Two hours later I was at the Olympia like a crazy bitch", she remembers. "But then songs will make you do crazy things. They'll make you cling to an airplane seat all the way across the Atlantic Ocean, crying all the way for your kids and cling to the seat all the way back doing the same thing - all just to sing two songs. I was climbing over the bedrails on whatever meds I was on. I really wanted to sing that night."

In some ways, she seems to thrive through adversity. Her best records have often come about in times of personal turmoil and this one is no different. I'm Not Bossy, I'm The Boss is a tour de force of infectious pop, and one of the highlights in a career full of them. It took its title from the Sheryl-Sandberg-and- Beyonce-backed campaign to get away from using the word 'bossy' for assertive girls and although the Facebook CFO personally reached out to her after the album title was announced, Sinead didn't want to particularly make it a political statement. "I wanted to make this record first and foremost about songwriting", she tells me. "Chuck Berry said that songwriters should write about the stuff that kids were into in school: cars, boys, girls, sex, music. Most of the blues catalogue is love songs. It's all about feel - which corresponds to what [her Bel Canto singing teacher] Frank Merriman said: the emotion will take you to the notes. When I was making this record I was standing in the studio and imagining how [Chicago blues legend] Muddy Waters would present it - not that I wanted to sound like him, because this is not a blues record, but how in his heart would he present this. [Blues legend] Howlin' Wolf is another person I was thinking of. He is one of my performance idols."

The original title of the record was The Vishnu Room, which is also one of the standout tracks on the album. It is sung from the viewpoint of a bride who feels under pressure to perform on her wedding night, and asks her man if she can just lie with her head on his chest instead "because Vishnu lives at the core of your heart." One interviewer recently expressed bemusement that an ordained priest, which she is, would find solace in Hindusim, but Sinead has long studied the faith and on her bedroom walls images of multi-armed Gods sit alongside the guitars - "If (Hinduism) was good enough for the Beatles, it's good enough for the rest of us," she tells me. And, besides, her one niggling problem with priesthood - aside from the Church trying to bar the way for women getting ordained - was always the chastity.

Hinduism, is after all, "a much more sexual religion than Catholicism." She explains: "The Kama Sutra is a Hindu scripture. I mean, there's even instructions for women on how to conduct a threesome! Not only is there no sexual guilt but sex is thought of as a connection with the divine."

She's still "flexible enough for all the positions" she tells me, slyly adding, "I did ballet as a child."

Has she had any threesome experience? "Well, I did spend one very exciting Sunday evening at a sex club in London, sandwiched between a cop and a bare-knuckle fighter. I'd been quite hormonal. They were best mates, these two. The cop had arrested the fighter and they'd made friends. I was the safest woman in the place. (It was the) best sexual night of my life."

She adds, "I went to a sort-of sex party once too, in Dublin. It's not my scene though. Seemed like everyone wanted to join in. I preferred the club thing. You could just hang out with who you liked."

Occasional bursts of sexual adventure aside, she doesn't believe in monogamy, she says. "I've loved loads of people in my life", she tells me. "I consider myself an extraordinarily loving person. I get crushes on people. I'm not a cheat. I don't sleep around, I really don't. But if I was to pick one song (on the new album) that sums up how I am in that regard it would be Kisses Like Mine. Because, as the lyric there goes, I'm just not 'the keeping kind.' I just love everybody. And I mean it when I'm there."

It's that kind of presence and laser-like sincerity in the moment, however fleeting, that may give her live performances their visceral intensity - she calls herself "a Stanislavski method singer" and talks of "inhabiting characters", especially on her latter records. But it may also be that this kind of magnanimity about her own nature and needs which has left her friendly with most of her former partners and husbands. "We'll probably all end up living in a house together because we're really good mates", she tells me. Recently she hosted a joint birthday party for her daughter Roisin (18) and son Shane (10). It was attended by journalist John Waters, Roisin's father, and trad music legend Donal Lunny, Shane's father, as well Californian businessman Frank Bonadio, the father of her youngest child, Yeshua (7) and her husband Barry Herridge. "And at one point Frank pipes up 'is there anyone here who hasn't slept with Sinead? And Barry pipes up, 'yeah me!', which was hilarious.''

It's a happy home, full of light and colour, and for her kids - she also has a grown-up son, Jake, with John Reynolds - assuredly a very different upbringing to the one she had herself. It's sometimes said that the most barren soil can produce the most vivid blooms but still it hardly seemed possible that the oppressive atmosphere of 1960s and 70s Ireland - the soundtrack to which was showbands and the Angeles - would bring forth someone like Sinead. She seemed rooted in the country's idealised past - she was named after the wife of the first Taoiseach and delivered at birth by his son - and, both in her family life and in her art, a break from that past. As has been well documented over the years she suffered serious emotional and physical abuse at her mother's hands and her father (who wrote his own well-received memoir last year) became only the second man in the country to gain sole custody of his children.

In her teenage years, she went to several different schools and the stultifying atmosphere of the times makes her smile now: "I remember being in Sion Hill in Blackrock and this old nun walked into the room and drew this enormous big hard dick - in one continuous sweep of the chalk - and we fell on the floor clutching ourselves laughing. We had never even seen a dick that didn't belong to our brothers. Why did she do it? And how did a nun know how to draw such an accurate looking penis, balls and all? Anyway, that was the limit of my sex education."

Her music education would continue, however. She would later spend time at An Grianan Training Centre, a corrective school in Dublin that had once been one of the most notorious Magdalene laundries for unmarried mothers, and other 'fallen women.' By the time she arrived there in the early 1980s the place was no longer the grim institution it once was although she still found it a terrifying experience. Life wasn't all bleak there, however. One of the nuns, realising that music was the only thing that would keep this wayward teen from going further off the rails, bought her a guitar and found her a teacher. From then on, singing was her life; and while still in her mid teens she won a recording contract and moved to London where fame and fortune were waiting for her.

Years later, when venom rained down on her after she tore up the picture of the Pope, in protest against the Church's cover-up of endemic child abuse, she remembered those formative years. "I grew up in a theocracy", she tells me, "but I took on the good aspects of it. I believed in Christianity. I believed in the Church. I believed in the Holy Spirit. And I saw music as a set of prayers to that Spirit. I saw myself as in a contract with that Spirit. A lot of artists wave around their awards and thank God but (in the early 1990s) there was a battle in the street for the honour of God and there was tumbleweed. I had to do something."

The performance also marked her retreat from the white-hot spotlight of megastardom, not that she had any regrets about that.

"The music business is for pimps and hoes," she tells me. "And the higher the level, the greater the devil. As Brian May put it, the irony is that you get into rock 'n' roll because you want to be a bit of a rebel. But when you're in it they try to make you conform and the more successful you are the less control you have over your life. It's a spiritually corrupt arena. Most musicians are sensitive people and it's a f**ked-up job for those people."

Only half jokingly she tells me that her advice to aspiring performers would be "run" and adds that she would "build a Rapunzel tower" if her beautiful daughter Roisin, who happens to have a gorgeous voice, wanted to make a living out of singing (she doesn't, having set her sights on becoming a writer). But how would Sinead feel about taking up a position as a mentor-judge on The Voice, as was suggested by Kathryn Thomas? Surely she would have a lot of wisdom to pass on to aspiring singers? "I'd love to do it, although I can't this year, as it happens", she says. "I think I would be good as a singing teacher. On those shows many are called and few are chosen - they really are about encouraging people to be celebs or whatever more than anything else. Out of 100 I would say you will have one or two who will be hungry to be a singer, like I myself was, and who would sleep in the park to do so. Those are the kids I would be interested in."

She says she's "been around for long enough now that people do associate me primarily with music" and as she gets older - she's 47 now - the overarching message of the new record - that self love comes before all others - is one she tries to embrace.

"There's a song on the record called 8 Good Reasons (which has the lyric) "…and maybe nine now", she says. "That's me. It can be uncomfortable to be stuck in a place you don't belong. I'm a 22nd-Century woman in a 20th-Century country. I was getting all these signals about how dreadful I am. Then, as you get older, you get a better sense of identity - who you actually are. Child abuse, which I went though, is an identity crisis. Fame is an identity crisis too. It took me until I was in my mid forties to realise who I am. You stop editing yourself and giving a f**k about trying to please everyone."

Perhaps the one time when she need have no qualms about "pleasing" people is when she steps onstage. Over the last few years her live shows have met with almost universal acclaim and her performances have garnered five-star reviews in the UK and American press. She's itching to let Irish audiences hear the new tracks. "When I was younger I wrote songs because I needed to get stuff off my chest", she tells me between thoughtful drags of a cigarette. "Now I'm writing songs for the love of writing songs. The love of that music and being engaged in watching that music - that's what I want people to feel."

Sinead O'Connor will play the National Concert Hall on August 16 - tickets from €40 available from nch.ie

Her new album I'm Not Bossy, I'm The Boss is available now on iTunes and from sineadoconnor.com

Sunday Independent