Today our “Word for the Day” and “Tech Tip of the Day” are combined. We have three related words to add to the library having to do with room modes. A room mode is essentially a “bump” in a room’s frequency response that is facilitated by the room’s dimensions and the way those dimensions cause soundwaves to interact with each other. There are three types of room modes: axial, tangential and oblique.
Axial Room Mode:
Axial Modes involve just two parallel surfaces – opposite walls, or the floor and ceiling. In other words, an Axial mode consist of waves resonating only along one dimension such as the length, width or height of the room. Normally the axial modes have the most strength while the oblique modes have the lowest strength. Often times the Axial modes are less of a problem than both Tangential and Oblique modes – though there is still a need for correction in most circumstances.
Tangential Room Mode:
Tangential Modes involve two sets of parallel surfaces – all four walls, or two walls the ceiling and the floor. In other words, Tangential modes involve two dimensions, the length & width, length & height, or width & height of a room and are about half as strong as Axial Room Modes. Room modes can interfere with accurate referencing, and are best dealt with by purchasing and properly installing acoustic treatment in your room.
Oblique Room Mode:
Oblique Room Mode involve all six surfaces – four walls, the ceiling and the floor. These are about one quarter as strong as the Axial modes, and half as strong as the tangential modes. Oblique modes are the ones that most often become overly excited.