Lennart Ăstlund, born in 1956 in Järfälla, Sweden, is a sound engineer and producer best known for his work at the legendary Polar Studios in Stockholm. He played a key role in shaping the sound of some of Swedenâs most prominent artists during the 1970s and 1980s. Ăstlund began his career as a sound engineer at Polar Studios when it opened in 1978. Together with colleagues Leif Mases and Michael B.