Along with the conventional rock band instrumentation, Pink Floyd added prominent synthesisers to their sound. For example, the band experimented with an EMS VCS 3 on "Brain Damage" and "Any Colour You Like", and a Synthi A on "Time" and "On the Run". They also devised and recorded unconventional sounds, such as an assistant engineer running around the studio's echo chamber (during "On the Run"), and a specially treated bass drum made to simulate a human heartbeat (during "Speak to Me", "On the Run", "Time" and "Eclipse"). This heartbeat is most prominent as the intro and the outro to the album, but it can also be heard sporadically on "Time" and "On the Run". "Time" features assorted clocks ticking, then chiming simultaneously at the start of the song, accompanied by a series of Rototoms. The recordings were initially created as a quadraphonic test by Parsons, who recorded each timepiece at an antique clock shop. Although these recordings had not been created specifically for the album, elements of this material were eventually used in the track.