In the early ‘10s, DJ Mustard suddenly became hip-hop's go-to producer, as his signature uptempo, bass-heavy groove became the template for radio rap. But ever since he emerged as a brand name, Mustard has been exploring the breadth of his sound. YG's "Left, Right" ratchets up the earth-shattering impact of Mustard's thunderous drums, while the slinky, ambiguous tone of Ty Dolla $ign's "Or Nah" expertly matches the lyrics' anxious uncertainty. Fabolous and Eric Bellinger's "4 Digits", meanwhile, is an understated, melodious R&B gem.