In 1957, Swiss musician Bruno Spoerri (born 16 August 1935) joined the "Metronome Quartet", which became "Metronome Quintet", until 1975 when he left. His arrival marked a new era in the group, as even when he left another musician became a member, and so it always remained a quintet until its end in 2013. His arrival was also the beginning of the groups touring in Europe, and later in Japan in the Expo '70 in 1970.