Jesse Kardon, better known by his alias Subtronics, is an American dubstep DJ and producer from Philadelphia, Pennsylvania, United States. He is known for his song "Griztronics", a collaboration with Michigan-based electronic music artist GRiZ that peaked on Billboard's Hot Dance/Electronic Songs at the No. 9 position in late 2019. Kardon peaked at No. 10 on Billboard's Next Big Sound chart in September 2019. Kardon is known for his mixtape series Now That's What I Call Riddim though he has stated the mixes are not riddim despite the name. Originally released in February 2017, the series has grown to five volumes, with most containing mashups, exclusive mixes, and unreleased music as well as various DJs and producers introducing themselves during interludes. The fourth iteration, Now That’s What I Call Riddim Vol. 4, contains around 110 songs from a large number of artists. A fifth installment was released in January 2020. Kardon marked it as the last in the mix series and included songs by Skrillex, Excision, Doctor P and Boogie T.