As heat is taken away from a fluid, its particles. slow down and come closer together. ï®. This causes the fluid to contract â its volume. decreases. ï®. This causes the density to increase. (D=M/V if V gets smaller, M/V gets bigger) ï®. Viscosity will also be affected, as particles slow. down and come closer together, it gets harder. for them to move past each other. Therefore, viscosity increases.
The commercial kind are probably $250 on up. You can get a nice Shure brothers mike for around $120. Their SM-58 is good for recording and amplifying voices, and the SM-57 excels at recording or amping musical instruments. Sennheiser is a long-time company that also makes several lines of mikes (or mics, if you prefer) that range from home-use to phenomenal studio use.
The 640A/AA condenser mic came about from Western Electricâs need for a reliable calibration mic and the conclusion that the 394 condenser was too big and bulky to do the job. In 1932, a miniature condenser microphone system with a one-inch diaphragm called the D96436 was successfully tested and re-designated the 640A.