[Dixielandjazz] The mystery of B Flat

Robert S. Ringwald robert at ringwald.com
Wed Feb 21 13:47:32 PST 2007


Listmates, regarding a Bb 57 octaves below middle C.  I sent the following
question to Les Deutsch.  Les is the pianist for the Night Blooming Jazz
Men.  He is also a Doctor of Mathematics and has a very prestigious job high
up at Cal Tech where he works with or for NASA in the  space program.

(snip)
Les,
>>
>>How many cps or -cps would Bb 57 octaves below middle C be?
(snip

>From Les:

(snip)
> Bob,
>
> First of all, no one uses cps anymore. Nowadays we all say Hertz
> (abbreviated to Hz.)
>
> However, the analysis in your attached email is correct. The Bb above A440
> has a frequency of about 493.88 Hz. You then divide this in half for each
> octave you descend. This gets you quickly to number less than 1 Hz. This
> is not a problem. Remember that humans picked the "second" as our unit of
> time fairly arbitrarily. If we had picked something a lot shorter (say 10
> to the minus 50 seconds) then this low note would still be measured in big
> numbers of whatever the new Hertz unit might be called.
>
> It doesn't take much to get music below the range of human hearing. A
> human with good hearing can detect sounds down to something like 10-20 Hz,
> yet many pipe organs generate tones down to about 8 Hz.
>
> Lots of things exist that oscillate on scales much less than a Hertz.
> Clearly the Earth's rotation - or better yet our orbit around the sun, are
> such oscillations - but these are not sound waves.
>
> Structural engineers have to deal with resonances in large structures -
> like bridges and skyscrapers. These are measured in small fractions of Hz
> and are critical to having the structure survive stresses of similar
> frequency - like Earthquakes or wind vibrations. The resonances are
> typically not measured directly - but rather are calculated from models of
> smaller parts of the total structure.
> away!
>
> Les
 >(snip)

 





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