Re: Tuned Metal Bodies

[William Lippe <lippe@xxxxxxxxxxxxxxxx>]

On 19 Oct 1994, Winslow Yerxa wrote:
> I'm still not convinced that a harp that pings when you strike it
> is tuned to a particular frequency that has any special relation
> to the notes of a harp.
> 
> You've probably tried playing a harp into a cup or glass, right?
> It gets louder and fuller-sounding. Likewise, if you play it
> through an old gramphone horn like Will Scarlett sometimes does,
> you can make it amazingly loud.
> 
> While the horn, which is made of pressed paper fibers, won't ping,
> a jar or glass will. There may in fact be an easily identified
> resonant frequency in that ping. And yet the jar or glass (or
> pingless paper horn) will still amplify frequencies other than its
> resonant frequency.
	Here's an experiment everyone can do at home, well.. maybe.  But 
it entails finding some tube, with a diameter which fits your mouth 
decently, so that you can "buzz" into it, or just get that glass/tumbler 
Winslow was talking about, and whip out your harmonica.  For the paper 
tube, begin buzzing at a low frequency, and with a fair amount of 
control, slowly raise the frequency of your buzz.  You should hit a 
frequency that gets incredibly loud, and then settles back to the normal 
volume.  The glass may or may not do this with the harmonica, depending 
on what key harmonica you are using, and the size and shape of the 
glass.  I believe this would happen with a harmonica, and that if the 
body's resonant frequency is the 1st position root, that note will be 
very different in tone and volume.  What I see as the major potential in 
this idea (Yeah, like I know what I'm talking about), is the idea of 
using a denser, harder material.  Sound travels through granite at 
speeds, which other than eluding me at the moment, far exceed sound waves 
in air, I would surmise that a harp made of metal (if I had _any_ extra $ I 
would have played a Meisterklasse) would get more reverberation, and more 
harmonics, thicker tone, etc...  I bought a $2 harmonica at a local fair 
as a novelty item (and it sure is), and the body seems to be made from 
some wood like balsa or bass, very light.  The tone produced is clean, 
very clean, and lacking in any warmth.  Another prospect I see is 
designing the harp with different prongs of different structure, each of 
which would be meant to capture different frequencies, and amplify them.  
Sure the body has a resonant frequency, but every dimension _within_ the 
body also contributes.  This is getting complicated.  I have no idea of 
what calculations would be needed to figure this out.  I think I'll stop 
flapping my lips and wait for either a review from Winslow or some other 
"beta tester" (I hereby volunteer), or till Kevins or Farell carry it.