| Author |
Subject |
Bob
Blais
Registered
User
(3/24/01 10:11:04 pm)
Reply |
Fingerboard tuning?
Has anyone heard of fingerboard
tuning?
Bob
|
DWThomas
Registered User
(3/24/01 10:52:33 pm)
Reply |
Re:
Fingerboard tuning?
I seem to remember this was touched
on a while back, maybe during a major examination of wolf tones. (Or
maybe I read it on the bowed string newsgroup ... think I may be
CyberSpaced out 
)
I'm pretty sure there was some intrepid experimenter on
this very board that claimed improved tone after they wacked a
centimeter off the fingerboard that they thought was overly long.
Shorter is easy, if it wants to be longer, you're in
trouble!
The fingerboard is a cantilevered structure that
would resonate at some specific frequency, at least when open
strings are being played. I would intuit that where that frequency
is relative to other instrument resonances could certainly influence
the sound. It could very likely affect how even the response would
be across the range of the instrument. With the fingers stopping
strings, especially in higher positions, I would think any such
resonances would be damped quite a bit.
I'm having this flash
that someone in an earlier thread posted a link to a (Canadian?)
luthier's website that had a fairly long article about the various
resonances in an instrument. Hopefully one of our real hardware
aficionados will remember.
I do have several links bookmarked
for some hairy stuff regarding violin family instruments (Chladni
patterns in top plates, etc.) , but I don't see anything among them
about the fingerboard. The Catgut Acoustical Society site might be
another place to investigate.
Dave
|
TerryM
Registered User
(3/25/01 8:12:23 am)
Reply |
Re:
Fingerboard tuning?
Dave, I am not sure if you were
referring to the post I made with the contents of an e-mail from a
luthier friend of mine regarding the fingerboard. It was part of the
discussion about cutting the fingerboard without knowing what
specific effect it might have on the overall resonance of the
instrument. This is the contents of that note that I posted
previously.
"Concerning your fingerboard, I would not touch
this without a having a good reason, that is knowing why.
Fingerboards come from the supplier at a standard length of 600 mm,
and as you stated this is usually cut to a length of about 580mm,
Weisshaar states 578 - 583mm, however this is not written in stone
for the following reason. Violin makers use the fingerboard of celli
to adjust the AO to the BO frequencies of the instrument, because it
is very beneficial if these two frequencies match.
AO is the
first air-frequency or 'Helmholtz' frequency of the instrument.
Where this frequency is found depends on the size of the aircavity
of the instrument, other factors like wall compliance play only a
very minor role. This AO frequency is fixed with the design of the
instrument, cutting down the rib height would of course raise it.
For a full size cello, it is usually found just below 100 Hz, mine
are around 92/93 Hz for the Strad model cello that I have been
building. At that frequency the air is actually puffing out the
f-holes.
BO is a body resonance of the instrument. At that
frequency the whole body of the instrument vibrates like a xylophone
bar with three nodes across the body at the widest part of the lower
bout, near the neck/body joint, and near the nut. The free end of
the fingerboard vibrates a lot at this frequency and therefore can
be used to tune the BO. It is a question of mass and
flexibility.
So the answer is, that depending on how these
frequencies are positioned now, simply shortening the fingerboard
could make the instrument better or
worse."
Terry
|
DWThomas
Registered User
(3/25/01 9:54:22 am)
Reply |
That
sounds like it!
That "AO and BO frequencies" has a
familiar ring -- at least it confirms I didn't imagine seeing it.
There's little doubt in my mind that when one sums up all of the
little diaphragms, links, levers and various structures that make up
a string instrument, even with computer help, the ultimate model is
elusive at best.
Ol' Antonio probably had a knack for noting
little correlations early in his career -- if tapping the top here
sounded just a tad lower/higher than tapping the bottom there, he
had a good one, etc.
Thanks Terry,
Dave
|
Beaker1
Registered User
(3/25/01 11:50:47 pm)
Reply |
another
solution?
The Luthier who works on my cello
(it was made in his shop) applies a puddy to the back of the finger
board to make the fingerboard resonate at a desired frequency. Just
a thought.....
|
Christopher
Chan
Registered
User
(3/30/01 4:12:54 am)
Reply
 |
Re:
Fingerboard tuning?
More info on the A0 B0
stuff.
www.marymt.edu/~cas/research/articles/modetune/
| |
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