Tempo changes in performance
When you open the concert you plan to use in your performance, MainStage uses the tempo for the concert you set in the Concert Inspector. If the “Get tempo from MIDI input” checkbox is selected, MainStage uses incoming MIDI beat clock to set the tempo. For information about setting and changing the tempo in a concert, see Tempo overview.
If you select a patch or set with its own tempo setting, the tempo changes to the new setting. You can also change the tempo in real time while you perform using the Tap Tempo feature, either by pressing Control-T repeatedly at the tempo you want to use, by clicking the Tap Tempo button in the toolbar repeatedly, or by using a screen control mapped to the Tap Tempo action.