📌 Key takeaways
- Geezer Butler, founding member of Black Sabbath, uses an AI-generated voice in his solo songwriting process.
- This artificial voice is used solely as a vocal demo, intended to guide guest artists as they lay down their vocals.
- Butler is thus tapping into a vast catalog of unreleased compositions, some written several decades ago.
A groundbreaking (or controversial?) way of working in rock
At Steel City Con 2025, held in Monroeville, Pennsylvania, Geezer Butler made an intriguing revelation for heavy metal fans: he now uses an AI-generated artificial voice to shape the vocal parts of his new songs during the writing process.
Historically, Butler has been a discreet yet influential songwriter within Black Sabbath, often celebrated for his deep, cavernous bass lines and his ability to structure profoundly dark songs. While he had already written solo albums in the ’90s and 2000s under the names g//z/r, geezer, and GZR, not having a singer available at home often held back his creative flow.
With the advent of AI-assisted vocal generation technology, everything changed.
“What held me back before was that I didn’t have a singer when I was at home... but then AI came along. I use it now to get the lyrics of my songs out,” Butler shared during the session.
This statement sums up a profound shift: rather than relying on a real voice during the composition phase, Butler prefers to incorporate a synthetic vocal version that highlights the melody, expression, and potential phrasing from the earliest stages of creation.
A tool for collaborating with real singers
What sets this approach apart is not so much the use of AI as a final performer, but as a communication tool between the songwriter and a human singer.
Previously, an outside singer often had to imagine or improvise over a bass line and an instrumental structure—a delicate task when the songwriter could not clearly demonstrate how they envisioned the vocals. Now:
- Butler generates an AI vocal sketch based on the lyrics and the mood of the song.
- This demo serves as a clear reference for the singers he wants to collaborate with afterward.
- It allows the singer to quickly understand the mood and vocal intentions before bringing their own color to the final track.
This process is not just practical: it ushers in a new form of human-machine-human dialogue, in which AI acts as an artistic bridge rather than a creative substitute.
Looking back at Butler’s musical past, and toward the future
This solo project comes at a particular moment in Butler’s career. After Black Sabbath’s final show, Back to the Beginning, in July 2025 (their last major onstage gathering), he dove back into a vast amount of musical material he had written over several decades—ideas, riffs, and songs that had sometimes been set aside.
Butler explained that he had amassed “tons of stuff” since the ’80s. With AI, he is able to “update” each of these songs, test them vocally, and quickly determine which ones can develop into a full production.
This personal musical laboratory recalls Sabbath’s early songwriting days: back then, they would get together, jam for hours, and refine every riff until a solid idea took shape. Today, artificial intelligence is becoming a creative partner in that process, offering Butler a modern way to bring a musical vision to life that might otherwise remain unfinished for years.
AI in music: tool, inspiration, or cheating?
The use of an AI voice by such a respected figure in metal is bound to spark reactions. Some purists may see it as a form of “cheating”—a technological aid that dilutes the human essence of music creation. Butler himself acknowledges these criticisms, even if he puts them into perspective.
Rather than viewing this technology as a substitute for artistic expression, he uses it as a clarification tool, a vocal intermediary that gives his instrumental ideas a clear melodic awareness. The goal is not to replace a human singer, but to ease the transition from a riff or an abstract verse to a fully embodied performance.
In a musical world where the boundaries between human and machine are becoming increasingly blurred, Butler’s example opens up a fascinating discussion:
- How is AI redefining the role of the voice in composition?
- How far can—or should—an artist rely on technology to bring their ideas to life?
- And above all, where is the line between an assistive tool and creative substitution?
These are all questions this solo project is about to explore—on and beyond the metal scene.
What this suggests for Geezer Butler’s solo album
The release date for the upcoming solo album is still unknown, but one thing is certain: this project will probably be unlike anything Butler has done before.
- It should include final human vocal performances, possibly from several different singers.
- AI is only the first filter—a fully articulated vocal demo that helps bring rich collaborations to fruition.
- This process could give rise to more diverse songs, with each voice bringing a unique color to the often heavy and complex structures written by Butler.
In conclusion: a cornerstone for the creative future of music
What Geezer Butler is doing with artificial intelligence is not simply a technology anecdote in rock. It is a turning point in how established artists can rethink the role of the human voice in the creative process, and how they use new technologies to fuel inspiration rather than replace it.
Far from simply seeking a futuristic gadget, Butler is exploring a hybrid artistic territory, where humans and machines co-write upstream what vocal talents will then shape. Perhaps it is there, at the crossroads of human intuition and algorithmic power, that some of the great songs of the future will be born—and Butler’s solo venture could well be one of the first major examples in the world of metal.
