This work-in-progress paper presents prototypes of three tangible user interfaces that provide an interactive physical display for sound controls, such as step sequences, envelopes or sample playback rates. They use mechanical actuators in combination with sensor technology, that enables the interaction with the physical representation itself. The prototypes were developed as part of the research project Tangible Signals. In the paper, each prototype will be presented separately, including the discussion of concept, interaction modalities, hardware design and possible use cases.