Cavity resonances in ducts is a classical problem that has involved researchers from very different fields over time. More recently the aerospace community became engaged again due to resonances found within the flow path of aero-engines, for example in bleed cavities in the low pressure compressor section. These resonances can lead to problems with the structural integrity of upstream components, and thus warrant investigation. The paper compares the results of the same cavity geometry within two wind tunnels of different dimensions and operational setups. The intention of the study is to isolate the Rossiter modes from any other geometric modes that are due to the wind tunnel's test section geometry. This isolation allows the modification of the model of Rossiter and the cavity depth model of East to improve the predictive capability over a larger range of Mach numbers and for deeper cavities. The experiments were performed for an operating range from low subsonic to transonic Mach numbers. The analysis focuses on modifying the constants in both the Rossiter model and the cavity depth model proposed by East along with investigating the phenomenon of mode switching for Rossiter modes. The analyses show a good repeatability of the data set between the two wind tunnels displaying strong resonances at similar operating points. An independence from Reynolds number of the acoustic frequency generation is demonstrated within the operating range. A mode switching behavior is identified with the shallowest and deepest cavity showing multiple mode transitions within the operating range.