Place a metronome app into the system bar of a mac system. Access it quickly and select the available features such as tempo and track adjustment, interactive display of the visuals, modification of the tick variance, including times less than 0.5 ms.
A handy metronome that uses minimum screen real estate.
Designed for musicians who want to keep a metronome ready all the time.
* Tiny: hidden inside the system status bar.
* Precise: tick variance less then 0.5 ms on modern machines, internal precision up to 0.2 ms.
* Requires external speakers to be fully usable. The volume of this application is relatively low, so built in speakers will not be able to produce enough volume to be heart when playing with another loud instrument, even when the system volume is set to maximum.