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Low frequency noise absorption can be obtained with a thin multi-resonant material as the subwavelength pancake absorber which is composed of thin annular pores periodically arranged in series and connected through a central perforation. This type of acoustic metamaterial has a first absorption peak at low frequencies and thin secondary peaks at medium frequencies, making it more suitable for tonal noise absorption. This work investigates a geometrical variation of the central perforation within the material thickness to broaden the material sound absorption efficiency. An analytical approach based on lumped elements and transfer matrix approach is used to predict the material behavior and investigate multiple profiles of the main pore. The analytical model is verified by comparison with a thermo-visco-acoustic finite element model of the material. It is shown that the main pore profile can be designed so that the secondary absorption peaks are moved closer to each other, thus creating an efficient broadband noise absorber at both low and medium frequencies.