Naretha Williams stares ominously from the cover of her new LP Blak Mass, hands outstretched as if performing an incantation. Standing in front of a large organ, this image of the Wiradjuri conceptual artist, composer and musician is unsettling, the kind of scene that precludes a curse. Those who press play on the disc inside, though, are far more likely to find a revelation.

Blak Mass is a fearsome work, a piece of music that utilises Melbourne Town Hall’s Grand Romantic Organ – the largest of its kind in the southern hemisphere – to ask questions about the nature of colonialism. A 33-minute composition commissioned by the City of Melbourne last year for the Yirramboi First Nations Arts Festival, Williams’ piece combines pummelling organ with elements of techno and avant-garde electronic to create an intense, magnetic work that dares its audience to reconsider both civic and personal history.

Williams’ work focuses largely on themes of identity, place and the unseen, making the Town Hall’s organ a perfect site for her composition. A part of her ongoing Cryptex project, in which the artist uses her own biodata as a starting point for composition, Blak Mass provides an opportunity for Williams to insert the viewpoint of a First Nations woman into histories from which they have previously been excluded.

“The organ is kind of loaded on a number of levels. It structurally, within itself, is massive,” Williams tells Guardian Australia by phone from locked-down Melbourne. “I’m considering what the impact of that is within the enormous walls of the Town Hall, and how that sits on sacred Aboriginal land. I’m also reflecting on its roots as a liturgical instrument – its roots within the church, and the outcomes and effects that the church has had historically on society and communities of people.”

Williams’ work considers the ramifications of forced religion and removals of First Nations children from their families. In that context, the sound of the organ – usually an instrument to evoke rapture, to bring one closer to God – becomes violent, uncanny.

Williams’ work asks listeners – many of whom in Melbourne would have some casual relationship to both the organ and the place it is situated – to reconsider what they may know, or think they know, about both. The imagery accompanying Blak Mass seems designed to evoke horror – black and red publicity photos, a vinyl that looks as if it was pressed from blood – and, like a horror film, the work hinges on the familiar becoming terrifyingly unknown.

“The organ itself is gloriously gothic, and the content that I’m exploring is also very tied to talk about skeletons in the closet, for us as people, and the community in the city,” Williams says.

The work does threaten to overwhelm its audiences, due to both its conceptual framework and the nature of the composition itself – a visceral, rarely heard mix of electronics and organ.

“I spent a lot of time digging around and trying to get an understanding of the instrument itself – what was happening, the air pushing through the pipes – how it was designed, what it was designed to do,” Williams says. The organ had been retrofitted with MIDI, a technical standard that allows musicians to control it through computer interfaces. This gives an electronic artist such as Williams the ability to program predetermined sequences, sync the instrument up with synthesisers or drum machines, and transcribe any organ work back to her computer.

Williams hopes Blak Mass will encourage listeners “to remember, to acknowledge what has happened” around the site of the Melbourne Town Hall, and “to acknowledge the role that the colonial aristocratic decision makers had at that time”.

The music, she says, is designed to put listeners on edge. “It’s meant to be triggering. It’s meant to be unsettling. It’s meant to be uncomfortable. That was all very, very deliberate.

“I know that it’s a very intense response, but I feel like it is an appropriate response when I’m considering the issues and the trauma and the ongoing impacts on Aboriginal people here,” Williams says. “In lots of ways, it really is time to face the music, so I make no apologies about presenting it in the way that I have.”