Keep reading to learn a bit more and to try it yourself – after all, the app is free. While their app has allowed DJs to carefully craft mixes from iTunes and Spotify for a while, the recently released update adds a “Collaborate” mode that allows mixes to be a shared project. Pacemaker – one of many smartphone DJ apps – is doing something unique that we haven’t seen before: collaborative DJ set programming.The Party Mix provides a dual deck setup with each deck offering a jog wheel, gain control, a 2-band EQ, pitch slider, and four color-coded pads.