Rebetiko is an urban popular musical tradition that emerged in the first half of the twentieth century, linked to Greek‑speaking communities within a cosmopolitan and translocal sphere spanning the Greek nation‑state, the Ottoman Empire, and the United States. In this context, phenomena of musico‑cultural amalgamation associated with the musico‑cultural trajectories of rebetiko figures and their work remain inadequately assessed and are frequently confined to ethnocentric and hegemonic readings rooted primarily in the East–West dichotomy and its implicit expressions. Through the lens of historical ethnomusicology and drawing on Foucault’s notion of heterotopia as an analytical and interpretive tool, this paper re‑examines the concepts of makam modality and chordal harmony, focusing on how their theoretical incompatibilities are negotiated and transcended through performative practices of rebetiko musicians. Contextualizing the philosophical concept within the musico‑cultural field of rebetiko, heterotopia is understood as a subject‑centered theoretical model: representation-contestation-inversion. This heterotopic framework underlines how the performers enact the representation of modal and harmonic topoi, contest them as they are inverted, thereby engendering a new, other topos: a modal heterotopia as an expression of musico‑cultural amalgamation in rebetiko. To do so, I examine the makam Saba and its pertinent guitar harmonization through musical‑textual analysis of representative gramophone recordings and their interpretation within historical musico‑cultural contexts. The terms "equal‑tempered makam" and "idiosyncratic harmonization," introduced as manifestations of modal heterotopia in rebetiko, illustrate the transcendence of the theoretical incompatibility between makam modality and chordal harmony through rebetiko musicians’ performative practices, offering a fresh lens for decolonizing rebetiko discourse.