20 Etudes (Neuheit Posaune) 20 Etudes for Bass Trombone by Karl Stefaniszin have been edited by Jörg Richter. These excellent etudes are a must for bass trombone or tenor trombone with f-attachment as they challenge the performer with quick changing arpeggios using a myriad of accidentals. Concentration is crucial to success. Herr Richter has inherited these great etudes through his teacher and his teachers teacher. They were misidentified for many years, also known as the Stefanofsky Etudes. In this edition, the student learns about the history of these etudes and also is given valuable practice tips by Richter and contributor Gordon Cherry.