Re: Low frequency dispersion - Was: Five string bass (Hermann Stemberger )

Subject: Re: Low frequency dispersion - Was: Five string bass
From:    Hermann Stemberger  <hermann@xxxxxxxx>
Date:    Fri, 2 Feb 2007 19:53:32 +0100

Brian wrote: > the lowest notes of which would crack concrete and cause submarines to > divert course 3,000 miles away. Hello Brian, how do you think your sound is not masked by some other louder than yours after 3000 miles? Even if your initial sound level (in dB SPL Linear) would be at the mark of ~160 dB(LIN) SPL, where the physical threshold for sound is, there will not be much left after 3000 miles because of the inverse square law that says -6dB per doubling distance. 160dB SPL at 1 meter makes 68 dB SPL at 40 km (~30 miles). 4000 km (~3000 miles) lowers it to 28dB SPL. A that low frequency is even with the 68dB(LIN) SPL value under the hearing threshold (0 phon curve). And it will be masked by many industrial low frequency noise from the region at 68dB SPL. Of what low frequency have you been thinking of? 32 strings does not say how they are tuned. Don't you think that the rule of inverse square law also applies for that frequency? How would your "bass" be that you could achieve that? How can you crack concrete with low frequencies? I thought you have to get material resonating at a frequency to get feedback. Is the resonance-frequency of concrete low? I thought this would just apply to osciallating structures, like houses or bridges (30 Hz - one wavelength is 11 meters) - they have low frequency resonances because of the size of their buildings, not because of their material - at least I thought so. Am I wrong? Regards, Hermann

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