The 432 Chamber Orchestra is Bulgaria’s newest chamber string orchestra. It has 13 players and 1 conductor. It was founded in November 2013 in Sofia and his conductor since then is Ivan K. Yanakiev. The Orchestra can be distinguished among the numerous other string ensembles by its specific way of tuning – the 432 concert pitch. Alongside with the application of the open fifth (Renold, 1985) they create the so-called “432 Sound”. In 2014, the prominent Bulgarian composer and conductor Academician Prof. Vassil Kazandzhiev expressed his astonishment that even though the Orchestra consisted only of 13 players, it sounded as if a big string orchestra was playing. The mission of the 432 Chamber Orchestra is to guarantee the listener’s right to choose to experience music in the natural 432 concert pitch. The Orchestra exists as an option to the standardized (by ISO 16/TC 43) sound of the professional ensembles. We can hear the 432 concert pitch, the most prominent trait of the Orchestra, and its natural existence: in the songs of the birds; in the folklore music – by both singers and players; in the spiritual music – during orthodox offices; and most importantly, in the melodious speech of the children. Yanakiev’s hypothesis is that 432 concert pitch may be considered a phenomenon, which is a part of the natural occurring sound. His observations also show that the temperament and the concert pitch can affect the attitude of the players and the listeners towards the process of music making. In a1 = 432 Hz and “open fifths” temperament the essence of the music (i.e. the idea beyond the notes) can be clearly heard and felt by the listeners, while the personality of the player seems to melt and vanish away. Just the opposite happens in a1 = 440 Hz (ISO 16/TC 43) – the personality of the player now overwhelms the entire music expression and the listeners receive not the pure musical essence of the piece, but the subjective, emotionally tainted experience of the player instead. In this regard, Yanakiev is preparing series of psychological and psychophysiological experiments in Sofia. In 2015, 432 Chamber Orchestra made its debut on the Bulgarian concert stage with two concerts – 18th May in “Studio 1” of the Bulgarian National Radio and on 22th December in “Dr. Long” Church, Sofia. In 2016 the Orchestra is preparing series of concerts in Bulgaria, starting on 13th March in Studio 5, National Palace of Culture. The ensemble is nominated in Bulgarian National Radio’s survey “Musician of the year” (the results are expected in the beginning of May).