In the mid-nineteenth century, Hermann von Helmholtz developed a new, mathematically formalized representation of the quality of tones, which he termed musikalische Klangfarbe. He did so at the price of excluding change from this representation and from the sounds he experimented with. Later researchers and composers discovered the cognitive and aesthetic side effects of this new concept. Experimental psychologist Carl Stumpf found that stable tones veil their source; their recognition strongly depends on their characteristic beginnings and endings. Arnold Schoenberg in turn used this effect to merge the sounds of musical instruments into new orchestral colors. On the basis of a three-part case study, I argue that nineteenth-century research in perception has deeply affected twentieth-century concepts of music, bringing to the fore the aesthetic quality of experimental situations.