Top and bottom plots represent respectively the threshold pressures and threshold frequencies given by the linear stability analysis (blue) and the continuation method (orange) versus the lips’ resonance frequency in the case of a euphonium. The circles identify the value of corresponding to a local minimum of blowing pressure. In the case of the second regime, the easiest note playable is given by the minimum of the continuation method (orange curve), since its minimal threshold mouth pressure is lower than the one given by the linear stability analysis (blue curve). The first two regimes on the left of each plot represent respectively the pedal note and the ghost note.