By 1956 rockabilly was firmly established as a very popular genre, with songs by Elvis Presley, Carl Perkins and Johnny Cash all breaking the top 5 on Billboard’s charts. Johnny Cash and Elvis Presley particularly, continued to experience a high level of mainstream success throughout the rest of the decade. Rockabilly can be characterised mainly through the instruments used and some recording techniques. Bands typically include both electric and acoustic guitar, an upright bass and a vocalist. Drumming was less important as the nature of the music is highly rhythmic and upbeat. The vocal style is heavily blues based, as are the chord progressions used. Recording techniques such as echo, or more specifically slap-back echo, tape delay and reverb were very common in rockabilly songs.