Archaeologists have relied almost exclusively upon sight among the five human senses to investigate architecture, features, and artifacts. In recent decades researchers have explored how ancient people may have experienced sound, because it was an essential component of lived experiences in ancient societies. Natural and culturally constructed spaces had acoustical properties that enhanced social, political, economic, and ritual events. This article investigates through the lens of archaeoacoustics the large domed earthen temazcal that residents constructed at Joya de Cerén during the seventh century a.d. Its uniqueness at this Classic-period Maya village in El Salvador has attracted considerable interest due to its exceptional preservation and distinct shape. Fortunately, in 2012, architects were able to construct a precise replica for public access. Through the years, visitors entering the replica have noted how significantly their voices were altered, once inside. To evaluate scientifically these observations, two recordings of sound were made and analyzed acoustically. The earthen dome morphology causes “preferred frequencies” to be sustained for a long time, while nonfavored frequencies diminish quickly. The predominant resonance is at 64 hertz, a tone so low that basso profundo singers can barely achieve it. The internal morphology greatly accentuates voices of mature males, but not those with higher pitches, such as mature females or children. The acoustical environment may have been utilized by men for divination, education, curing, rites of passage, and other functions, some of which have not been previously considered. The nature of the lived experience in a socially charged performance space is explored here with new insights regarding how the sweatbath was vital to all in the community.