Sound amplification by stimulated emission of radiation phenomenon, known as the Larsen effect, is the result of a positive feedback. In general, every oscillator consists of three main parts. These are the power source or pump, the amplifier and the positive feedback leading to the output. The corresponding parts in a SASER device are the excitation or pumping mechanism, the active (amplifying) medium, and the feedback leading to acoustic radiation. Pumping can be performed, for instance, with an alternating electric field or with some mechanical vibrations of resonators. The active medium should be a material in which sound amplification can be induced. An example of a feedback
A Sound Garden A Sound Garden A Sound Garden is one of six outdoor public art works on the National Oceanic and Atmospheric Administration (NOAA) campus that lies adjacent to the Warren G. Magnuson Park on the northwestern shore of Lake Washington in Seattle, Washington. The Seattle Arts Commission guided the jury selection headed by Sadao James Hilario, Engineer-in-charge of the GSA Art in Architecture Program for the NOAA Project, and the jury chose five artists from a pool of more than 250. Designed and built by sculptor Douglas Hollis from 1982–83, "A Sound Garden" is a sculptural group composed of 12 21