From "Straight Outta Compton" on, Dre uses live musicians to replay old melodies rather than sampling them. With Ruthless Records, collaborators included guitarist Mike "Crazy Neck" Sims, multi-instrumentalist Colin Wolfe, DJ Yella and sound engineer Donovan "The Dirt Biker" Sound. Dre is receptive of new ideas from other producers, one example being his fruitful collaboration with Above the Law's producer Cold 187um while at Ruthless. Cold 187 um was at the time experimenting with 1970s P-Funk samples (Parliament, Funkadelic, Bootsy Collins, George Clinton etc.), that Dre also utilized. Dre has since been accused of "stealing" the concept of G-funk from Cold 187 um.