Naked Science Forum
Non Life Sciences => Technology => Topic started by: syhprum on 16/01/2020 10:44:15
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Large loud speakers have been used to address people on the ground from aircraft how does the sound output power compare to a big ben bong
The power input to the bell is easily calculated if one knows the weight of the hammer and how far it falls but how efficiently this is converted to sound power is unknown.
Loud speakers are commonly quoted as having a conversion efficiency of about 1% while input powers are quoted at ridiculous high figures as the power factor is ignored.
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It’s been measured at 118dB (which I assume would be SPL @ 1m and probably A weighted) which will cause pain for some people. That’s why it was shut down while people were working on it.
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I have been in the bell tower of Köln cathedral when the bell was struck but followed the advice to cover my ears and suffered no ill effects
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Small propeller aircraft (you wouldn't use a jet for a loudspeaker) generally produce less than 70 dB at 500 ft, so an 80 dB speaker will do the job for public address. You may need a bit more for a helicopter but police-type activities use a very directional horn speaker so the off-axis signal (and hence power requirement) can be quite small.
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Big bong... probably not what you were thinking of...
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Depends how far you are from it.
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I haven’t heard it myself, but I think not very much. Already for three quarters at the modern level of automobile traffic you will not hear.