An AI Music App's Own Detector Is Now Flagging Two Rappers' Songs as AI-Generated

Key points

• Fenix Flexin's "Rubberz," which reached number 58 on the Billboard Hot 100 in summer 2025, has been flagged as "Very likely Treblo" by an AI music detection tool.
• Treblo, a generative AI music app (software that composes full songs from a text prompt), built and published its own detector after independent producers accused two artists of using it.
• Rapper Tyga's track from his $TARFACE project returned a result of "Likely Treblo" when run through the same tool.
• Treblo's cofounder confirmed the company had no contact with either artist and was unaware "Rubberz" existed until it appeared on the Billboard chart.
• Treblo says its detector produces fewer than one false positive in every ten thousand tests, though that figure has not been independently verified.

Sometimes the most damning witness is the tool itself.

Fenix Flexin spent the summer insisting "Rubberz" was recorded the old-fashioned way. His producer denied it too. No mainstream AI detection service flagged the song. Fans arguing about whether the track was AI-generated had nothing solid to go on.

Then Treblo, the little-known AI music app that independent producers were already pointing at, published its own detection page last Sunday night. Feed a song into it and the tool tells you whether it was made with Treblo's software. "Rubberz" came back "Very likely Treblo." A track from Tyga's recent $TARFACE project came back "Likely Treblo."

How did this start?

Suspicion about "Rubberz" began the day it dropped on 5 June. It's a synth-pop track in the style of moody 1980s pop, a sharp left turn for an artist known for gritty Los Angeles rap. The voice is completely unrecognisable from Fenix Flexin's familiar nasal delivery. He told a Channel 5 interviewer he had freestyled the lyrics and was simply using a fake British accent with heavy reverb.

The case against him sharpened last Thursday when a music producer named Medasin posted a video laying out his theory step by step. He pointed to an Instagram Story Fenix had posted teasing new music. Freeze the frame and zoom in: the file shown on screen carries the suffix "Sonauto.mp3." Sonauto was the previous name of Treblo, changed two days before "Rubberz" came out.

Medasin went further. He opened Treblo, typed in tags like "80s synthwave" and asked it to write lyrics about a rapper's lifestyle. The song he got back shares multiple phrases with "Rubberz": both have lines about heavy diamond chains, faces seen in glass or champagne bubbles, and the phrase "pockets thick." His own attempt produced the couplet "Rings on every finger / Leather seats and cedar scent linger," a close match to "Rubberz"'s "Gold rings on my fingers / Still your perfume lingers."

Our 1 August story on the "Rubberz" accusations noted that experts had already flagged glitchy drums, an impossible vocal range, and lyrics that read like a chatbot on autopilot.

Does the detector prove anything?

Not conclusively, but it's hard to dismiss. Treblo says its tool is tuned specifically to catch songs made with its own software with little or no editing, and it claims a false-positive rate below one in ten thousand. The company has released the underlying code as open-source software, meaning anyone can inspect and test it freely.

Treblo cofounder Ryan Tremblay told Wired AI the company had no prior contact with either artist. "Someone appears to have used our model to find a sound that millions of people connected with," he said, "and that's exciting."

Fenix posted what he said was the original studio project file for "Rubberz" on Instagram after Medasin's first video, then deleted it within hours. Producers who commented before it came down said the file looked like a full song broken apart using a "stem separator," software that splits an existing track into its component parts. That move proves nothing either way. Neither Fenix nor his producer has responded to requests for comment.

Should you worry about the broader pattern?

This story is about more than one summer track. AI music tools are now capable enough that even longtime fans may not recognise when a voice has been replaced or heavily altered. File names and metadata visible in shared screen recordings can accidentally expose the software used, as happened here. A detector result is not a conviction, and a clean result doesn't guarantee a song is human-made. Denials from an artist or label are not evidence either way without verifiable proof attached.

The detector code is public. Researchers and journalists can test it themselves now, which is the fastest route to knowing whether Treblo's one-in-ten-thousand claim holds up. That's the number worth watching, not the chart position.

If major labels get their way, it may not matter much longer: as we reported on 31 July, Universal, Sony, and Warner have already drafted rules that would strip fully AI-generated tracks from official charts worldwide.