The Open Seminar on Acoustics is an annual conference, the largest acoustics conference in the country. It has been bringing all Polish acousticians together for over sixty years. It is organized in turns by different divisions of Polish Acoustical Society – in 2019 by the Poznan Division with the Institute of Acoustics, Adam Mickiewicz University in Poznan and Committee on Acoustics of Polish Academy of Science. The conference presents all sections of acoustics, such as: physical acoustics, technical, environmental, speech, hearing, musical, architectural acoustics, etc. The seminar is joined with special session “New trends in psychoacoustics in tribute to professors: Józef Zwisłocki and Andrzej Rakowski” and the Workshop “Noise protection in regulations – current state and directions of changes” (in Polish). We also invite you to the special session “Advances in research in the field of audio acoustics and sound engineering – ISSET 2019”.