The nature of the group's music had by now completely changed into jazz-rock, and had evolved into a similar vein to that which the Mahavishnu Orchestra, Weather Report, and some progressive rock bands were performing at the time. Their music was still relatively melodic, relying on strong themes, but the jazz element was by this time almost entirely absent, replaced by a more direct, rock oriented approach. Over-driven, distorted guitar had also become prominent in the band's new sound, and Clarke had by then switched almost completely to electric bass guitar. A replacement on vocals was not hired, and all the songs were now instrumentals. This change did not lead to a decrease in the band's commercial fortunes however, Return to Forever's jazz rock albums instead found their way onto US pop album charts.