Systems and methods for forming button assemblies for electronic devices are disclosed. According to some embodiments, the button assemblies include one or more sound improvement features to improve the sound that the button assemblies make when pressed by users of the electronic devices. According to some embodiments, the button assemblies include shims that provide proper alignment of the various components of the button assemblies and to accommodate any tolerance stack up of the various components of the button assemblies. The shims can include alignment features to prevent the shims from shifting within the button assemblies. According to some embodiments, thicknesses of the shims are customized to accommodate varying tolerance stack ups of the components of the button assemblies. In some embodiments, the button assemblies include a combination of sound improvement features and shims.