This article focuses on the Italian inventor, telephone pioneer and opera house technician Antonio Meucci (1808–1889), exploring the shifting relationships between Meucci’s experiments and his operatic connections across his transatlantic career. Meucci first developed an acoustic telephone while working at Florence’s Teatro della Pergola, before discovering the transmission of sound via electricity during his tenure as chief machinist at Havana’s Teatro Tacón in the 1840s. These experiments were further refined after his relocation to New York, where he continued to be part of a network of Italian musicians, thinkers, journalists and scientific practitioners while seeking to patent his invention. Feted among the Italian diasporic community in the USA – both for his technological innovations and for his close relationship with Italian revolutionary Giuseppe Garibaldi – at the time of his death Meucci was nonetheless embroiled in a lengthy legal case against Alexander Graham Bell over the primacy of the telephone’s invention, a dispute not fully resolved until the twenty-first century. This article accordingly unfolds in three main parts, focusing in turn on Florence, Havana and New York. Meucci’s experiments – and his complex emigrant environment – collectively highlight the Italian opera house as a global and multidimensional site of technological and sonic innovation, during a period when the telephone gradually moved from conceptual fantasy to material reality. At the same time, Meucci’s career can challenge direct links between Italian sonic environments and Italy itself. Ultimately, I argue, the complex and changing relationships between opera and the telephone invite more nuanced approaches to histories of music and technology, while demonstrating the centrality of the Italian opera house and its sounds – within, across, and beyond the stage – to nineteenth-century auditory cultures more broadly.