Dear Doctor,
Actually I just looked this up in my book here, and I will explain it like
this.
One needs a fixed, solid air cavity with an opening. As one increases
the size of the opening it lowers the air space resonance, period!that is
science. Bob actually has it ass backwards!
I actually don't really get what Bob is talking about because he is not
using science and I have a hard time following him.
Bob talks about blowing into the soundhole and hearing something.
What Bob is actually hearing is what is called "mode coupling". that is a
phenomena were you are hearing both the air resonat frequency coupling with
the frequency of the vibrating plates to create one frequency,as on a lute
or guitar.
If however, the plates where not able to vibrate and had a fixed air
cavity you would only hear the air resonance frequency.
This really is not up for debate it is pure science, no matter how Bob
trys to sell it!
Michael Thames
Luthier
www.ThamesClassicalGuitars.com
Site design by Natalina Calia-Thames
----- Original Message -----
From: "Doctor Oakroot" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, December 11, 2003 9:41 PM
Subject: Re: a rosette by any other name...
> Michael, your physicist friend didn't understand the problem. As Bob
> described it the amount of beer in the bottle during the experiment was
> fixed. Only the size of the opening changed.
>
> Michael Thames wrote:
> > I've just spoken to my physicist friend, and he explained it like this.
> > When you have a beer bottle and blow into it, the pitch changes
according
> > to how much beer ( air volume) is in the bottle.
> > Bob, what has the most significant effect on the pitch is how much
beer
> > you consumed during your experiment!
> > Michael Thames
> > Luthier
> > www.ThamesClassicalGuitars.com
> > Site design by Natalina Calia-Thames
> > ----- Original Message -----
> > From: "BobClair or EkkoJennings" <[EMAIL PROTECTED]>
> > To: <[EMAIL PROTECTED]>
> > Sent: Thursday, December 11, 2003 8:48 AM
> > Subject: a rosette by any other name...
> >
> >
> >>
> >> Philippe Mottet <[EMAIL PROTECTED]> writes:
> >>
> >> > I think M. Thames is right when he mentions that a bigger opening, a
> >> > rosette with a longer diameter and an airy (?) motive, tends to favor
> > bass
> >> > and fundamental resonances.
> >>
> >> And you, also, would be incorrect. I'm not trying to be mean or rude,
> >> you
> > are entitled to
> >> believe whatever makes you happy. But unlike some more subjective
> >> things,
> > like whether a
> >> note is "sparkling" or not, the pitch of the main air resonance of a
> > guitar or lute or violin
> >> and what happens to that pitch as you make the hole(s) in the top
> >> smaller
> > (it goes down) are objective
> >> things that you can easily measure with a simple experiment. They are
no
> > more influenced by how you think
> >> or feel about them than is the height of the Eiffel tower.
> >>
> >> As for "this particular rose design causes those particular tonal
> > qualities" - there are just way too many
> >> variables involved. Making such a statement on the basis of one or two
> > instruments is nothing more
> >> than a superstition. To make any meaningful statement you would have to
> > make two batches of otherwise
> >> identical instruments with twodifferent rose patterns and then show
> >> that,
> > on average, a pair with different
> >> roses had a significant difference in the quality you were testing for
> > compared to a pair with the same rose design.
> >> At this point it would be wise to recall a statement attributed to
> >> Michael
> > Lowe: "An exact copy of a historical instrument ?
> >> I can't even make an exact copy of one of my own instruments."
> >>
> >> Pendulums ? Divining ? Dowsing? Mysterious Energy ? My contract with
the
> > Physicist's Union has a clause limiting
> >> the amount of time I have to spend arguing with believers so I will
just
> > leave with a single
> >> word: "unlikely".
> >>
> >>
> >> .....Bob
> >>
> >> ____________________________________________________________
> >> ____________________________________________________________
> >>
> >> Replies: (remove the "ZZZZ")
> >>
> >> Ekko Jennings: [EMAIL PROTECTED]
> >> Bob Clair: [EMAIL PROTECTED]
> >>
> >>
> >
> >
> >
> >
>
>
> --
> Rough-edged songs from a dark place in the soul:
> http://DoctorOakroot.com
>
>
