Room within a room
A room within a room (RWAR) is one method of isolating sound and preventing it from transmitting to the outside world where it may be undesirable. Most vibration / sound transfer from a room to the outside occurs through mechanical means. The vibration passes directly through the brick, woodwork and other solid structural elements. When it meets with an element such as a wall, ceiling, floor or window, which acts as a sounding board, the vibration is amplified and heard in the second space. A mechanical transmission is much faster, more efficient and may be more readily amplified than an airborne transmission of the same initial strength. The use of acoustic foam and other absorbent means is less effective against this transmitted vibration. The user is advised to break the connection between the room that contains the noise source and the outside world. This is called acoustic de-coupling. Ideal de-coupling involves eliminating vibration transfer in both solid materials and in the air, so air-flow into the room is often controlled. This has safety implications, for example proper ventilation must be assured and gas heaters cannot be used inside de-coupled space. Structure is a fundamental, tangible or intangible notion referring to the recognition, observation, nature, and permanence of patterns and relationships of entities. This notion may itself be an object, such as a built structure, or an attribute, such as the structure of society. From a child's verbal description of a snowflake, to the detailed scientific analysis of the properties of magnetic fields, the concept of structure is now often an essential foundation of nearly every mode f inquiry and discovery in science, philosophy, and art. In early 20th-century and earlier thought, form often plays a role comparable to that of structure in contemporary thought. The neo-Kantianism of Ernst Cassirer (cf. his Philosophy of Symbolic Forms, completed in 1929 and published in English translation in the 1950s) is sometimes regarded as a precursor of the later shift to structuralism and poststructuralism. The description of structure implicitly offers an account of what a system is made of: a configuration of items, a collection of inter-related components or services. A structure may be a hierarchy (a cascade of one-to-many relationships), a network featuring many-to-many links, or a lattice featuring connections between components that are neighbors in space.A sounding board (also known as a tester) is a structure placed above or behind a pulpit or other speaking platform which helps to project the sound of the speaker. The structure may be specially shaped to assist the projection, for example, being formed as a parabolic reflector. In the typical setting of a church building, the sounding board may be ornately carved or constructed. In this context it is also known as an abat-voix. The term may also be used figuratively to describe a person who listens to a speech or proposal in order that the speaker may rehearse or explore the proposition more fully. The term is also used inter-personally to describe one person listening to another, and especially to their ideas. When a person listens and responds with comments, they provide perspective that otherwise would not be available through introspection or thought alone.