He is the founder, artistic director and conductor of the Lithuanian Chamber Orchestra, National artists of USSR, the holder of different prizes and awards. Born in 1928 in Shaulyae (Litva). Studied at Vilnius Conservatory as violinist in the class of professor A. Livont who was the pupil of P. Stolijarskiy, later in the Moscow conservatory in the class of professor D. Oistrakh. He also finished the conductor faculty in Conservatory, where his teacher was I. Markevich. In 1955 he was the head of the School of Art named after M. K. Curlenis. The students and teachers of the school have formed the Lithuanian Chamber Orchestra in 1960. In 1976 the school orchestra received the Gold Medal at the Herbert von Karajan Youth Orchestra Competition in Berlin. A lot of different works were dedicated to Maestro Sondeckis including such as Concerti grossi ¹ 1 and ¹ 3 by A. Shnitke and symphony ¹ 8 by S. Slonimskogo. In 1989 the conductor organized the chamber orchestra from students of Saint-Petersburg conservatory - "Saint-Petersburg Camerata" that in 1994 received the unique status of State Hermitage Orchestra. S. Sondeckis has led orchestras of Germany, France, Poland, Belgium, Sweden, Austria, Switzerland, among them the famous Berlin Philharmonic, Leipzig Gewandhaus, Radio and Television Orchestra of Paris, the National Orchestra of Belgium, etc. Maestro Sondeckis collaborates with distinguished Russian orchestras. He has conducted Sankt Peterburg Philharmonic.

S. Sondeckis was a guest conductor with various youth orchestras at the Bukovo (Germany), Youth Philharmonic of Belgium, Ost-West-Musikfest (Austria), and Davos (Switzerland) festivals. Maestro was invited to conduct the orchestra of Schleswig-Holstein Festival - the orchestra founded by Leonard Bernstein.

In Salzburg Festival 1988 S. Sondeckis led the orchestra of Hamburg Ballet Company in a production of "Otello". In 1994 Maestro conducted the "Magic flute" by W.A.Mozart at the Mariinsky Theatre in Sankt Peterburg; "Euridice" by Ch.W.GIuck and "Cosi fan tutte" by W.A.Mozart at the Hermitage Theatre. He was a member of Jury of David Oistrakh First Republican competition in Odessa in 1988.