Clicking will enable JACK transport. If disabled, Hydrogen will still use the JACK driver and registered audio ports. But it decouples its own transport state from the one of the JACK server and will not be in sync with other clients anymore.

Using Hydrogen can be registered as JACK Timebase Master and will send additional information, like the current speed, to other JACK clients. Else it will either act as slave in the presence of another Timebase Master, like Ardour, or as a stand-alone client in the absence of a Master.

	Tip
	You can check whether Hydrogen is in slave mode by hovering over the disabled Beat Counter or Timeline.

	Note
	The support of JACK Timebase can disabled in the Audio tab of the Preferences. This can be useful in the presence of a fault Master broadcasting nuisance information.