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Natural Science Forum / Physics / Acoustics / February 2004Sound Limits of Earth Atmosphere?
What is the upper limit of the frequency response of earth atmosphere? How much headroom does earth's atmosphere have? What is the dynamic range of earth's atmosphere? What is the signal-to-noise ratio of earth's atmosphere? > What is the upper limit of the frequency response of earth atmosphere? What's the separation distance? Noise floor? Sound pressure level? Directivity? > How much headroom does earth's atmosphere have? Compared to what SPL? > What is the dynamic range of earth's atmosphere? max is roughly 180 dB at sea level, somewhat less if you want to preserve linearity; I don't know the minimum. The minimum is probably well below any detectable limits, so it's not particularly interesting. I guess if you freeze everything to absolute zero, you'll get no motion and thus -infinity SPL. > What is the signal-to-noise ratio of earth's atmosphere? What signal? What noise floor? Troll factor: 0.95 (1 being definite troll, 0 being non-troll). Dave dvt at psu dot edu > max is roughly 180 dB at sea level, somewhat less if you want to You asked....... OK let's start with 180 dB at sea level, and let's suppose a hard source like a bell or a speaker (constant displacement amplitude). The SPL in planet Earth atmosphere reduces by a factor of 2 every 18,000 feet (ignoring temperature gradients... you figure!). There are 30 each 6 dB steps in 180 dB, so the altitude where the SPL goes to zero dB (for instance!) is 30x18,000'= 540,000', or about 102 miles (165 km). [I can just hear you guys saying "wow! I can just hear a sound at satellite altitude...]. Hey, these are just my approximations... better data is out ther somewhere. But it sort of agrees with the fact that sattellites decay due to "atmosphereinc drag". I'm outa` here. Angelo Campanella >> max is roughly 180 dB at sea level, somewhat less if you want to > [quoted text clipped - 12 lines] > approximations... better data is out ther somewhere. But it sort of > agrees with the fact that sattellites decay due to "atmosphereinc drag". Yeah, but you forgot to incorporate the warping of space-time in your calculations. :) Dave > > What is the upper limit of the frequency response of earth atmosphere? > > What's the separation distance? Noise floor? Sound pressure level? > Directivity? What is the highest frequency of sound that can exist in earth's atmosphere? > > How much headroom does earth's atmosphere have? > > Compared to what SPL? How many dB can exist in the earth's atmosphere? > > What is the dynamic range of earth's atmosphere? > [quoted text clipped - 5 lines] > > > What is the signal-to-noise ratio of earth's atmosphere? IOW by how many dB is earth's atmosphere affected by thermal agitation noise? > IOW by how many dB is earth's atmosphere affected by thermal agitation noise? If you really want a WAG, I say it is 20 dB below the human threshold of hearing. You guess is as good aaas mine. Angelo Campanella > > > What is the upper limit of the frequency response of earth atmosphere? > > > > What's the separation distance? Noise floor? Sound pressure level? > > Directivity? > > What is the highest frequency of sound that can exist in earth's atmosphere? No precise limit value. The higher the frequency the higher attenuation per m/ft of propagation path. > > > > How much headroom does earth's atmosphere have? > > > > Compared to what SPL? > > How many dB can exist in the earth's atmosphere? In explosions, e.g. in nuclear explosions, no precise limit value. This is: the positive or high pressure part/phase of a sound "wave" have no precise limit value, but the negative or low pressure part/phase can't be lower than vacuum. Kari Pesonen |
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