----- Original Message ----- From: "Vance Wood" <[EMAIL PROTECTED]> To: "bill sterling" <[EMAIL PROTECTED]> Sent: Sunday, December 14, 2003 9:56 PM Subject: Re: calling Dr. Helmholtz...
> Hi Bill: > > Freud said it best: "Sometimes a cigar is just a cigar". I was once told > that the rose was to keep rats from nesting in the Lute. I suppose that > makes about as much sense or nonsense depending on which side of the debate > you happen to stand. > > Vance Wood. > ----- Original Message ----- > From: "bill sterling" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]>; "Timothy Motz" <[EMAIL PROTECTED]> > Sent: Sunday, December 14, 2003 5:01 PM > Subject: Re: calling Dr. Helmholtz... > > > > I worried about that too, > > On my simplified model, I calculated between 109 and 139 Hz > > depending on the percent of the rose that was open. > > The actual resonance I found was a little above 116 hz, about A#. > > Not too bad. especially since I expected my rose to fall between the the > > upper and lower figures. > > It seems that the division of the total open area into all of the fiddley > > bits of the rose is not enough to make a big difference in the outcome. > > > > The Helmholtz resonance is just one factor in how the instrument works. > > Helmholtz resonance is just the acoustic property of a closed cavity > volume > > and an > > aperture. > > It does not consider the vibrational modes of the soundboard, the torque > > applied by the bridge to the > > soundboard, energy transfer to the other strings and the various ways that > > happens ...ad infinitum. > > > > After all of that, what I really learned is that in spite of the cavity > > resonance near A#, the loudness and > > responsiveness of this particular lute seems quite even over its entire > > range, no big hot spots or dead spots. > > > > bill > > > > ----- Original Message ----- > > From: "Timothy Motz" <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Sunday, December 14, 2003 2:10 PM > > Subject: Re: calling Dr. Helmholtz... > > > > > > > Okay, I'll admit that I'm too lazy to try the experiment myself. I'll > > > take everyone's word for it. But what, then, is the effect of the > > > lattice-like rose on the sound of a lute? Is it simply a combination > > > of the areas of all of the openings, or is more happening? Does > > > something different happen when you have a very complex rose pattern > > > from a simple one with bigger openings? > > > > > > I would think that all of the free edges of the rose pattern must > > > vibrate to add their own layer to the sound. Sort of like the F-holes > > > on a violin. And the wood of the rose pattern is thinner than the rest > > > of the soundboard, so it's resonant frequency must be different. But > > > then, I'm just barely following the explanation of the Helmholtz > > > effect. I was a Humanities major, so I'm hoping that Dr. Science can > > > explain it in terms I can understand :-) > > > > > > > > > Tim Motz > > > > > > > > > On Sunday, December 14, 2003, at 10:57 AM, Leonard Williams wrote: > > > > > > > Dear Dr. Helmholtz: > > > > I tried the experiment with an empty 12 oz. bottle. Using my > > > > Korg tuner I found that I was able to > > > > alter the pitch from an f# down to an e, even an eb. The higher pitch > > > > came with the completely open bottle > > > > neck; to get the lower pitch I placed my finger across the far side > > > > of the opening from where I was > > > > blowing. The pitch change was certainly noticeable without using the > > > > meter for a more precise analysis. > > > > Howard--the room did not move much, but I got the distinct > > > > impression that the lights were dimming! > > > > > > > > Leonard Williams > > > > [] > > > > (_) > > > > ~ > > > > > > > > ----- Original Message ----- > > > > > > > > Subject: Re: calling Dr. Helmholtz... > > > > > > > > > > > >> BobClair wrote: > > > >> > > > >>> Try this at home and report back. Take a wine or beer bottle. Fill > > > >>> it 2/3 full > > > >>> with water. (The change in pitch for a given change in area is > > > >>> bigger when the > > > >>> volume is smaller - patially filling it with water makes the effect > > > >>> easier to > > > >>> see (hear) but if you think this makes the results suspect leave the > > > >>> bottle > > > >>> empty). Blow across the bottle, note the pitch. Now cover half the > > > >>> opening > > > >>> with a > > > >>> finger. Try it again (it may take a bit of practice to get the > > > >>> note). Did the > > > >>> pitch go up or down? > > > >> > > > > > > > > > > > > > > > > > > >
