MEDDLE was the first album to hint at the musical identity that would define Pink Floyd in the mid- to late-'70s. Whereas prior releases like UMMAGUMMA and ATOM HEART MOTHER announced the presence of new singer/guitarist/songwriter David Gilmour, MEDDLE represents the band's Gilmour-influenced evolution toward a sleek, epic, spacey sound. In "Echoes," an ambitious 23-minute soundscape, the pinging of a synthesizer greets the listener before Gilmour's warm, open guitar and gentle crooning gives way to a repetitious, workmanlike rhythm. From here, the music fades into an abyss of whale calls and eerie sonic reverberations.

Elsewhere, Floyd dabbles with straightforward cocktail-hour jazz ("San Tropez") and a twisted slow blues ("Seamus"). But it is "One of These Days," MEDDLE's opening track and lone radio staple, that truly previews things to come. Roger Waters's bass, played through a Binson echo unit, establishes the song's manically hypnotic groove, as Richard Wright's synthesizer bursts in and out, Nick Mason's off-kilter drum fills get tossed around, and Gilmour's guitar dive-bombs through it all. These varied sound effects, packaged in a song that clocked in at less than six minutes, were a precedent for the masterpiece that was two years away: DARK SIDE OF THE MOON.