This paper discusses the influence of resonator folding and manufacturing inaccuracies on the performance of quarter-wavelength acoustic metamaterials. The discussed metamaterial structures all consist of one or more resonators with constant cross-section. First, the impact of resonator folding is assessed by means of a detailed finite element analysis (FEA). To this purpose, a basic single-resonator structure is modelled numerically and this process is repeated several times, each time changing the folding pattern. The absorption curves are then compared and the impact of difference in folding pattern on the resonance frequency and achievable absorption is assessed. The findings are validated experimentally using 3D printed metamaterial samples. Secondly, the influence of manufacturing inaccuracies observed in metamaterial samples, such as edge rounding or channel clogging, on the metamaterial performance is studied. To this end, representative geometrical inaccuracies are introduced in the aforementioned single-resonator metamaterial models. The results of these simulations are then compared to the performance of the ideal structure to assess the effect of manufacturing inaccuracies on a metamaterials performance preliminary.