This essay takes as its point of departure the so-called ‘Verdi A’, 432Hz. From the late 1860s through to the 1880s, the opera composer was intensely preoccupied with the question of tuning, weighing in several times on the matter of where A should sit. Verdi was concerned for the strain that high tunings should place on singers’ voices. He advocated on multiple occasions for global acceptance of an A well below 440, and sent Arrigo Boito to argue in favour of A=432 at the Congresso dei Musicisti Italiani, held in Milan on 16–21 June 1881. In the 1880s, Italy remained one of the only nations in Europe that had not adopted equal temperament wholesale for fixed-tone instruments; as in the case of its spoken languages during this same period, and the locations of its A, temperament varied by region, with the southern part of the peninsula clinging to meantones. This article argues that ‘Verdi tuning’ represents the end point of a number of longer shifts in the conceptualization of musical sound, particularly in the Italian context: from temperament to tuning (accordatura); from relative conceptions of musical pitch to an absolute one; from local and regional variations towards a standardized system; from an older notion of all-encompassing nature to a presumed separation between nature and culture. Tracing this history through the Italian long nineteenth century will involve concentrating on what this article calls music-adjacent sound: that is, interrogative play with musical pitch; sound experiments from musical materials and operatic voices; instrument tuning by ear; listening for overtones; legislating preferred ratios and (eventually) frequencies for musical use; and constructing a theory of music that draws together these means of sounding. Music-adjacent sound is where the conditions for music-making were and still are established. This article argues that an attention to these sonic and nearly musical moments can demonstrate how listening and the musical imagination were cultivated outside the boundaries of any work or performance.