Is 'Rubberz' an AI song? The evidence against Fenix Flexin is piling up
A rapper's unlikely synth-pop hit has experts pointing to glitchy drums, impossible vocal range, and lyrics that read like a chatbot on autopilot.
Key points
- "Rubberz" by Fenix Flexin reached number 58 on the Billboard Hot 100 chart in 2024.
- Five AI music detectors each estimated a 20 to 30 percent chance the song is fully or partly AI-generated.
- The single's cover art and a promotional post were flagged as AI-generated with over 97 percent certainty by multiple image detectors.
- AutoTune, the pitch-correction software most artists use, cannot extend a singer's vocal range or give them a foreign accent.
- Fenix Flexin has denied the allegations but has not shared original project files to settle the question.
Fenix Flexin built his name as half of Shoreline Mafia, a trap-rap duo from Los Angeles. So when "Rubberz" arrived as a dreamy, synth-driven track soaked in 1980s British pop influence, complete with a fake English accent and a vocal melody that sounds borrowed from Morrissey, listeners noticed.
Some liked it. A lot more started asking questions.
What actually sounds wrong with the track?
The recording carries telltale marks that audio experts associate with AI music generators, software that composes and produces music automatically from a text prompt or style instruction.
Songwriter Charlie Harding, co-host of the music analysis podcast Switched on Pop, told The Verge that the backing vocals "duck in and out unexpectedly" and that the drum reverb, the echo effect on the drums, is "full of unnatural digital artifacting reminiscent of a 64kbps MP3 downloaded off of Napster." He argues this happens because most AI music companies trained their systems on low-quality, compressed audio files, and that degradation bleeds into the output.
The hi-hats sound brittle. The chorus vocals have the muffled texture of a heavily compressed audio file. Reverb tails, the natural fade of an echo, cut off abruptly instead of dying away.
Then there are the lyrics. Lines like "Swipin' cards and stackin' chips, I saw you sinkin' ships" raise an obvious question: who is sinking ships? The image never comes back. The rhyme scheme is a simple AA, BB pattern, every line ending cleanly, which is exactly what a language model, the technology behind tools like ChatGPT, tends to produce when asked to write rap. Experienced rappers typically use internal rhymes (rhymes inside a line, not just at the end) and near-rhymes to create texture. There are none here.
Producer Curtiss King fed the lyrics into Claude, Anthropic's AI assistant, and it flagged multiple signs of AI authorship. Google's Gemini did the same.
What do the live performances show?
This is where the case gets harder to dismiss. In early in-studio appearances, Fenix lip-synced rather than singing live. When he does sing, he cannot match the vocal range on the recording, and in several clips the original studio vocals are clearly audible playing over his live attempt, kept low in the mix.
Fenix says the difference comes down to vocal processing, including AutoTune, the pitch-correction tool almost every modern singer uses. But music critic Anthony Fantano and Curtiss King both push back hard. King compares AutoTune to spellcheck: it tidies errors, it does not hand you a new voice. It would not give a West Coast rapper a British accent or extend his range by several notes.
Fenix has posted screenshots of what he says are Pro Tools session files, the digital workspace a producer uses to build a track. Screenshots prove little without the underlying files, and he has not shared those.
What does this mean for listeners?
You are not obliged to care whether a song was made by a person or a machine. But it matters for the artists whose work AI systems were trained on, often without permission or payment. Harding warns that even this relatively rough-sounding result found an audience, and that more capable AI music tools are already producing cleaner, harder-to-detect output.
