Few have done as much for salsa in Venezuela as band-leader, composer and pianist Ray Pérez. He burst on to the scene in the mid-'60s with his group Los Dementes, creating the blueprint for guaguanco, pachanga and boogaloo in Venezuela. When the name salsa began to be used as something of a catch-all-term he was still at the forefront, recording two hugely-popular salsa albums with Los Dementes in 1967. Remarkably, that very same year, he also recorded two albums with a brand new group, Los Calvos, that showed how as well as being the genre's most visible band-leader, he was also pushing the nascent genre to its limits. Looking back, revered journalist Alfredo Churion states that Los Calvos were "one of the most innovative experiences in Venezuelan popular music." 'Estos Son Los Calvos' is the first of the two albums he made with Los Calvos. On it, he made a few alterations to the line-up that may seem minor, but created a completely new sound. For the first time, he recruited a drummer (unprecedented at the time for a salsa ensemble, which always used percussionists), he switched from the trombones of Los Dementes to the much harder, direct sound of trumpets, and he recruited Carlos Yanez, best known as El Negrito Calavén, as singer. Whereas Los Dementes had been aligned with the slightly pop sound of tropical orchestras, Los Calvos took an almost-jazz approach, allowing room for the musicians and vocalists to improvise, and they also took inspiration from the sounds of surf rock swirling around Caracas. The group's drummer El Pavo amusingly once described the group's sound as like "wearing a dinner suit with flip-flops."