A controlled diffuser device can include a cover, a louver panel, a substrate member, and a base is disclosed. A cover and a base can be configured to affix to each other to sandwich a substrate member and a louver panel while enabling a substrate member and louver panel to slidably engage a base upper surface. A substrate member may comprise a material that changes in a physical dimension as it diffuses aromatic components. Because of static securement and slidable engagement configurations, a louver panel operatively shutters apertures of a cover to selectively moderate varying degrees of exposure of a substrate member as a substrate member changes in a physical dimension. Other embodiments may include a base configured to receive a substrate member and have a cover placed over top. As the substrate changed in physical dimension, the cover can be caused to move relative to the base.
