Michael B. Tretow was born 1944 in Norrköping, Sweden. As a youngster in the 1960s, he experimented with recording equipment in his room at home. Michael made some multi-overdub recordings of his own songs where he sang and played all the instruments himself.
The recordings led to a brief record deal, but more importantly, Michael also found employment as a sound engineer at Metronome Studio in Stockholm. In 1970 he started working in earnest with Björn and Benny, and the three young men hit it off right away. Michael had the patience to spend hours on getting exactly the right sound, which was a working method that suited Björn and Benny perfectly.
During the ABBA years, Michael was an invaluable source of inspiration for the group. He guaranteed a consistently high quality on the recordings, but was also keen to experiment and find new ways to acquire interesting sounds.
After the ABBA years Michael scored a couple of big novelty hits in Sweden, and he has written music for movies and commercials. During the 1990s, the continued sonic upgrading of the ABBA catalogue on CD was also one of his recurring tasks.