Results of the linear stability analysis with the constant, linear and inverse H-profile described on Figure 5. Top and bottom plots represent respectively the threshold mouth pressure and the threshold frequency versus the lips’ resonance frequency. Blue: H = h₀, orange: , green: . Circles point out the minima of each U-shaped pattern on the top plot. Red points represent the experimental values of minimal threshold pressures given by [19]. The black dashed line on the bottom plot represents .