Sound Signal – sounds which are meant to be listened to, measured or stored.

Very explicit sound signal is for example beeping sound of card reader upon entering classes or gates upon entering the building.

Keynote sound – Sounds which are heard by a particular society continuously or frequently enough to form a background against which other sounds are perceived

Backround noise of the corridors or dishes with cutlery on canteen.

Soundmark – a community sound, which is unique or possesses qualities which make it specially regarded or noticed by people in that community

Silent ambience of the library and the way to the library. Bridge right before entrance has high ceiling and it amplifies surrounding sounds with transition into hyper quiet environment of the library with occassional sound of turning pages.