Composer and music organiser. In 1983–88, he studied piano  with Kazimierz Gierżod, and in 1988–94 composition with  Włodzimierz Kotoński at the Chopin Academy of Music in Warsaw. He also took part at composition workshops led notably by  Hanna Kulenty, Henryk Mikołaj Górecki, Michael Nyman, Louis  Andriessen, and Tristan Murail. As a pianist and composer, he  has appeared at numerous contemporary music festivals, including Warsaw Autumn, Poznań Music Spring, Musica Polonica  Nova, and ISCM World Music Days.

He has won prizes at the International Competition for Jazz Composition in Słupsk (1997), Music and Play International Composers’ Competition in Poznań (1998), and Mikołaj’s Music-Making  Composers’ Competition in Rydułtowy (2011). He has received  scholarships from the Minister of Culture and National Heritage,  the City of Warsaw, and the Society of Authors ZAiKS. As a member of MM Group in the 1990s, he worked at the intersection of  theatre, music, and the visual arts. His cooperators have included  Eugeniusz Rudnik, Fryderyk Rzewski, Michelangelo Pistoletto,  the Viktor Lois/Yin Peet duo, and the Azorro Group. His compositions have been performed by the Polish Radio Orchestra,  Sinfonia Varsovia, Gorzów Philharmonic Orchestra, New Music  Orchestra, Orkest De Ereprijs, and the Forbidden City Chamber Orchestra. He composed the official bugle call of Rzeszów  City, as well as music for animated films (by Jan Lenica, Daniel Szczechura, Marcin Giżycki, Agnieszka Skolik, and Tomasz  Kozak, among others), theatre productions, and computer games.  For many years, he cooperated as a pianist and composer with  the Children’s Art Centre in Poznań, writing some twenty works  for its Music and Play project, many of which actively involved  young audiences in performance. A monographic CD of his  music appeared in the Polish Composers’ Union’s Polish Music  Today series in 2013. Since 2017, he has served as artistic director  of Warsaw Music Encounters, a festival organised by the Warsaw  Branch of the Polish Composers’ Union.

Siwiński’s work encompasses music in the conventional sense,  but often reaches beyond it. In 2019, the Museum of Modern Art  in Warsaw presented his installation Imaginary Chopin, featuring an autonomous piano without a pianist. In 2020, he obtained  a PhD at the Chopin University of Music with a dissertation  on the concept for a sound installation responsive to weather  conditions.

Selected works: The Misty Eye of the Earthworm for amplified  piccolo and two percussionists (1989), The Perception of Music is a Complex Process, Not Totally Clear for tape, piano, and violin  (1990), Notari, E.M. for tape (1992), Pianerecerto for piano and  ensemble (1994), Notarimbalo for harpsichord and tape (1994),  Dominotales for piano, percussion, and children’s audience  (1997), Piano Quintet (1998), Hominibus for orchestra (2002),  Locomotive for tape, to words by Julian Tuwim (2003), Polish  Songs for tape (2006), Movement for orchestra (2006), Annalena  for baritone and string orchestra, to words by Czesław Miłosz  (2011), Chopin Elements for autonomous piano (2012), Sestetto for piano, string quartet and double bass (2013), Variations and  Changelings for chamber ensemble, video and children’s audience,  to words by Małgorzata Kołcz (2013), The Other Side Turned Out  to Be for soprano and chamber ensemble, to words by Agnieszka  Syska (2014), Via caelestis for chamber ensemble (2014), Food  Items for woodwind quartet and tape, to words by Małgorzata  Kołcz (2015), Industrial Music for  traditional Chinese instruments ensemble (2015), HubTub for tuba and ensemble (2016),  On Variations and Changelings, educational animated film for  children (2016), Silent Fish, microopera for children to a libretto  by Małgorzata Kołcz (2016), Jeżeli / If for soprano, string quartet and autonomous piano, to words by Agnieszka Syska (2016),  Ornithology for soprano and chamber orchestra, to words by  Małgorzata Kołcz (2017), Soundscenes for ladder and various  other objects (2017), A Tale from a Shallow Sea for chamber  ensemble, after Joseph Conrad (2017), Three Coloured Figures for  two flutes and organ (2018), Imaginary Waltzes for autonomous  piano (2019), Aurea, electronic music (2020), Aria for flute, clarinet, violin and cello (2020), Gismondo for two flutes and piano  (2020), Trio for flute, violin, and piano (2020), I Still Can’t Learn  Harmony for tape (2024), There are Tritons on the Fountain, electronic miniature (2024).