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Table of sound levels L and correspondingsound pressure and sound intensityExamplesSound PressureLevel Lp dBSPLSound Pressure p N/m2 = PaSound Intensity IW/m2Jet aircraft, 50 m away140200100Threshold of pain13063.210Threshold of discomfort120201Chainsaw, 1m distance1106.30.1Disco, 1 m from speaker10020.01Diesel truck, 10 m away900.630.001Kerbside of busy road, 5 m800.20.0001Vacuum cleaner, distance 1 m700.0630.00001Conversational speech, 1m600.020.000001Average home500.00630.0000001Quiet library400.0020.00000001Quiet bedroom at night300.000630.000000001Background in TV studio200.00020.0000000001Rustling leaf100.0000630.00000000001Threshold of hearing00.000020.000000000001
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A loudspeaker system in a club might produce 1000 times that level (your poor ears). But that would only get you 50W of energy to play with.
Loudspeakers are very inefficient devices for turning electrical energy into sound only 2 or 3% so if we use them as moving coil microphones presumably we get very little out.The only application of converting sound energy into power was in some clocks that were powered by variation in atmospheric pressure which of course is a very low frequency sound wave but the power was only in the region of microwatts.
Why I use 10^-6 is because to write a high small 6 is beyond my typographical skills, I can manage 10‾6 but not the high 6 even If I try to use 'cut and paste' it does not come out right
Quote from: syhprum on 03/10/2007 21:32:03Why I use 10^-6 is because to write a high small 6 is beyond my typographical skills, I can manage 10‾6 but not the high 6 even If I try to use 'cut and paste' it does not come out right Use 10[sup]-6[/sup]Suggest you read http://www.thenakedscientists.com/forum/index.php?action=help;page=post#bbcref