In a passive loudspeaker system the low-level audio signal is first amplified by an external power amplifier before being sent to the loudspeaker where the signal is split by a passive crossover into the appropriate frequency ranges before being sent to the individual drivers.
A landform is a natural feature of the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography.
List of Landforms on Earth Types of Landforms and Definitions. Alluvial fan: land formation that occurs when sedimentary materials such as rocks, gravel, and silt, are deposited onto land as a result of decreasing or stopped water flow from a river or stream source.