Weather Report maintained a consistent interest in a textured sound and developments in music technology and processing. Both Zawinul and original bassist Miroslav Vitouš experimented with electronic effects pedals (as generally used by rock guitarists) with Zawinul using them on electric piano and synthesizers and Vitouš on his upright bass (which he frequently bowed through distortion to create a second horn-like voice). The band's third bass player, Jaco Pastorius, popularized the use of fretless bass guitar, melodic bass soloing and extensive use of string harmonics, as well as consolidating the driving R&B pulse in the band's music (which had been brought in by his predecessor Alphonso Johnson).