The aim of this study is to increase the understanding of how odd and even harmonic components contribute to the timbre of musical instruments. It is based on the acoustics of musical instruments, and especially on recent findings in psychoacoustics, which explain how harmonic colour is distinguished via sensory perception and how masking between the different components of sound works. The paper tries to grow the existing knowledge, and especially to numerically describe the relationships between even and odd components. In its core, the study is based on two listening tests conducted as part of the undergraduate theses of audio engineering students at the Faculty of Electrical Engineering and Communication (FEEC) of the Brno University of Technology. The results from these listening tests were linked to the above mentioned disciplines through logical connections, their relevance was evaluated and, where appropriate, new findings were generalised and the direction of further necessary research was indicated.