Budapest-based producer and DJ Matt-U, the stage name of Mátyás Szalai, began by making drum and bass before moving into dubstep. By the time he discussed that shift in an interview, he had spent five years producing drum and bass and was still collaborating in the genre. He was also a member of Soulproof. His releases began appearing in 2004, with work for labels including Moving Shadow, Timeless Recordings and Cylon. A 2007 single, Iron Skies, came out on Fokuz Recordings, adding another label to his early drum and bass work.
Matt-U’s drum and bass releases included the 2011 EP Straightened Up EP and the single Empty Inside / Unforgiven. He also released the 2011 EP Watchin U EP on Subway Recordings, followed by the 2012 single Straightened Up on the same label. In 2013, his releases included the Hammerhead EP and the Frequency EP. Other outlets for his music included Cyberfunk Records, Black Box and Osiris Music. His collaborations included Jade, SKC and DJ Madd; with Jade, he released the single Salem / Nightmare on Moving Shadow.
After a decade of releasing music, Matt-U launched Bad Seed Audio in 2015 with Dan, whom he had met through the Danger EP on Pressed Records. The label gave the partners greater control over releasing unreleased tracks, and its first release by Matt-U was an EP. His releases also included the single Bad Seed Audio 001 that year. Later work included #Swing, a 2016 single with DVST, Krutz and Manda on Digital Empire VIP, and the 2019 single head in a hoodie.
Matt-U has described varied musical influences and regular production as ways of developing his sound while remaining rooted in drum and bass and dubstep. His work with Killawatt included the track The Strangers, and he released the album Jade Presents the Venom LP on Citrus Recordings. The EP Whisper followed in 2022, extending a release history that spans both of his principal genres.