Kijanki makes a good point and worth expanding. Audio systems make distortion, and the distortions that we as humans find the most objectionable are the odd orders. In fact the human ear uses the presence of the 5th, 7th and 9th harmonics as a means of detirmining loudness.
If the structure of these harmonics is altered even by 100ths of a percent we can hear it. 'Harsh', 'brittle', 'clinical', 'bright', 'chalky', etc. are all audiophile terms that describe surprisingly small amounts of extra odd-ordered harmonic content.
If the structure of these harmonics is altered even by 100ths of a percent we can hear it. 'Harsh', 'brittle', 'clinical', 'bright', 'chalky', etc. are all audiophile terms that describe surprisingly small amounts of extra odd-ordered harmonic content.