As electronic effects became more sophisticated, with the development of digital signal processing, during the 1980s, there was some crossover between the roles played by electronic keyboards and electric guitar. Even though electronic keyboards or organs were the standard instruments used to create sustained "pads" of sound (e.g., held backing chords) for ballads, with the introduction of digital delay pedals and other modern effects, electric guitars could produce similar "pads" or "walls of sound". The Edge, the guitarist from the rock band U2, often used digital delay and reverb-drenched electric guitar arpeggios (chords played one note after the other) to create a shimmering, sustained "pad" for the group. These arpeggio pads created a sustained sound that was similar to the sound of an electronic keyboard. By the late 1980s, the price of digital effects pedals dropped, making these effects units available to the general public.