Long range directional microphones-myth and reality

There are a lot of myths about directed long-range microphones. You can here like they can reach distances of 100, 200 and more meters, others say that this is a myth and these numbers are commercial purposes. Let us try mathematically find proof and see the real situation. Introduction to long-range microphones When talking about directed microphones, usually we have in mind that sound sources are in the open air, and there are no reverberation effects. So the only factor is the distance of the sound source object from the microphone. Along the distance, sound power drops significantly, and in longer ranges, it interferes with other sounds like wind and other noises in the atmosphere. When the distance is about 100m sound pressure drops more than 40dB(comparing to a distance equal to 1m). If the sound level is 60dB then from 100m, you will hear 20dB. Sound level 20dB is less than other environmental noise, and many standard microphones are not sensitive enough for such sound level. So we can say that directed microphones must have: High sensitivity and selectivity from environment noises even if they have a higher level than real sound; High directivity to for excluding noise signals…

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