In 2004 the Beastie Boys released the self produced To the 5 Boroughs album. For the mix, the Beastie Boys called upon Ken Ifill aka "Supa Engineer Duro." Having mixed album tracks for hip-hop's elite, Duro has no problem getting the perfect sound out of a sampled loop or thump from a kick drum. Much has changed in the world of mixing and editing from back in 1986, when Licensed to Ill was recorded and mixed. Today, there is a greater reliance on software and computers. According to an interview Duro gave Digizine, To the 5 Boroughs was created with the help of ProTools and ProControl.

Many fans first became acquainted with Duro through the promotional "The Hiatus is Back Off Again" DVD. This disc began popping up on internet auction sites in the summer of 2004. Once a few of these promotional copies made it into the hands of online community, it was not long before DVD-R versions were being burned and traded amongst fans. The footage from the interview portion of the disc shows Duro in the Beastie Boys' Oscilloscope studio seated behind the boards. During the course of that footage, Mike D comments that it is easier to ask Duro which hip-hop albums he hasn't produced. Duro has pop sensibility too; some of other recordings he's worked on include: Will Smith's Big Willie Style, Mariah Carey's Heartbreaker and Rainbow. It will be interesting to see if the Beastie Boys call upon Duro again for help with their next album.