The Model 809 Microphone is designed especially for surface-mounted applications. It is a superior quality, permanently-biased (electret) condenser microphone with a hemispherical pickup pattern (omnidirectional in the hemisphere above the mounting surface).
The 809 is particularly suited for sound-reinforcement and recording of speech, singing, or acoustic instruments—in locations like churches, schools, conference rooms, and theaters. Whenever an inconspicuous high-output, high-fidelity omnidirectional surface-mounted microphone is desirable, the 809 is a logical choice.
The microphone design relies on the fact that sound pressure doubles at a barrier or boundary compared to its-value if the boundary is removed. When placed sufficiently near the boundary surface, a microphone has effectively 6 dB higher sensitivity and approximately 3 dB greater rejection of random background noise.
Because of its high sensitivity and extremely flat response, the 809 can be used for distant pickup in circumstances where close miking would not be practical. The fixed low-frequency rolloff permits using the 809 in some environments where low-frequency background noise (e.g., from fans or air conditioners) would otherwise make distant pickup unfeasible. The omnidirectional polar pattern of the 809 means sound is picked up equally in the full 360° hemisphere around the microphone; there is no off-axis sound coloration or variation.