Experimental laboratory research was performed to study the effect of test section width on the magnitude of acoustic resonance generated in a small pitch ratio staggered tube bank. Three different test section widths were studied: 505mm, 714mm, and 953mm. The results for acoustic resonance were compared to the tube bank data of Blevins and Bressler (1993, J. Sound Vib., 164(3), pp. 503–533), Ziada, Bolleter, and Chen (1984, ASME Symposium on Flow-Induced Vibrations, ASME, New York, Vol. 2, pp. 227–242); Ziada, Oengören, and Buhlmann (1989, J. Fluids and Struct., 3, pp. 293–324), and Fitzpatrick and Donaldson (1977, ASME J. Fluids Eng., 99, pp. 681–686). The present study showed that test-section width may be a significant factor in determining the maximum acoustic pressures generated by the flow. In particular, the simple relationship between maximum acoustic pressure and input energy parameter derived by Blevins and Bressler was not a reliable predictor for the array studied and will likely underpredict the maximum acoustic pressures in the lower modes of practical heat exchangers.