Tempo is undoubtedly one of the most pivotal building blocks of song composition. Measured in beats per minute, it dictates overall timing. This will in turn direct the speed and the feel. GarageBand uses a master tempo track here and informs how drums and loops perform within the project ‘grid’ or timeline. Beginners can set this to one static number, typically initialised to a standard 120bpm by default in new projects. It will rigidly stay this way from start to finish with no deviation. Thankfully however, more advanced users are able to change this with automation and adjust timing changes throughout.