The H sound is the beginning of collecting, synthesizing and materializing of inaudible sound. Hydrogen is a chemical element that in the periodic table is marked with the symbol H and his atomic number is 1. It makes 75% of the mass of the Universe and it has no colour, smell, taste or – sound. How to hear hydrogen? From visibility experiments to sound of spectral lines of the hydrogen atom, the installation is dedicated to exploring its existence and is the first one in a series dealing with sounds of formulas, elements, particles, movement and ideas. The installation was created in collaboration with Ana Kontrec from the Department of Mathematics and Tomislav Smolčić, under the mentorship of professor Dalibor Paar from the Department of Physics, both at the Faculty of Science in Zagreb.