| Author |
Comment |
ecmlee
Registered User
Posts: 21
(9/2/01 11:52:57 pm)
Reply
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Standard width
on top of bridge?
What's the correct width on top of the bridge where the strings
actually contact with? Some of the previous topics here suggested to
cut or sand away the top of the bridge in order to get the correct
string height. After I did that, the contact area between the
strings and bridge was increased (around 2.5mm now), and I noticed
that the sound is changed too. I think the width is too wide. Any
standard on this?
Eddy
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CelloBass
Registered User
Posts: 83
(9/3/01 11:45:20 am)
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Re: Standard
width on top of bridge?
Eddy,
recently my luthier did the setup on my 2 cellos,
including new bridges (completely new, not fitting the old ones). My
luthier is cellist. I have just measured their thickness. On both
cellos their width is exactly 2.5mm where the strings cross the
bridge. The old bridges where thicker, and the new bridges opened up
the sound. If you think that your bridge is still too thick and if
you want to sand it thinner because your cello sounds somehow muted,
make sure you sand only the side that is facing the fingerboard. The
other side, opposite to the tailpiece, is always left totally
plain.
Horst
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ecmlee
Registered User
Posts: 23
(9/4/01 9:36:04 pm)
Reply
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Re: Standard
width on top of bridge?
Horst
I just measured the width again and it is 4.5mm! This
is definitely too much and I will sand away a bit as you advised. By
the way, does it make a hugh different on sound by changing the
width of the bridge where the strings
cross?
Thanks!
Eddy
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TerryM
Registered
User
Posts: 553
(9/5/01 7:20:53
am)
Reply
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Re: Standard
width on top of bridge?
Something to keep in mind is that the bridge thins out toward the
top and it is the taper that must be maintained. Thinning the very
top may not be the way to go. It probably would have been best to
measure this taper before you took wood off the top so that you
could achieve the same taper in the newly shortened bridge. However,
one should be careful in just removing wood from the bridge without
some idea of what effect it will have, as doing this can greatly
affect the sound quality of your instrument in a negative or
positive way. Once the wood is gone and the sound quality is
degraded, the only recourse is to get a new bridge
fitted.
Terry
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CelloBass
Registered User
Posts: 84
(9/5/01 7:27:44 am)
Reply
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Re: Standard
width on top of bridge?
Hi Eddy,
wow, 4.5mm, that is what I have on my double
basses, and bass bridges are almost twice as big, in any direction!
They are 4.5mm. Yes, I am sure this thickness will mute the sound
because any additional mass that has to be moved when the bridge
transmits the vibrations means that the energy of the string is used
up to move the bridge and will not reach the top of the cello. I
don't know if you have experimented with mutes. Even a small and
light mute will dampen the harmonics tremendously. I have just
looked at my cello bridges. They are not sanded gradually, beginning
at their feet (thickness 11mm). The feet itselves and the arc that
connects the two feet has been left unsanded. My luthier has sanded
them thinner starting just below the heart of the bridge, about 3mm
below. I think this is to keep the stability of the feet. Maybe the
raw bridge of your cello didn't have the correct size for your
cello, and that is why it is that thick? There are bridges of
different quality also, depending on the age and hardness of the
wood. Good bridges are light (the wood has dryed out) and hard, you
can feel the difference if you have two bridges of different quality
in your hand. Fortunately my luthier is not this sort of
mystery-monger you sometimes find amongst luthiers. He shows and
explains all he does. Try to sand it down, but if the results are
not satisfactory, I would try to find a luthier who plays the cello
and have a new bridge fitted by him. My luthier explained to me that
there are different ways to sand the bridge thinner. Some cellos
require a heavier bridge to get a stronger low register. On those
cellos, he reduces the thickness of the bridge mainly at its top,
leaving the region around the heart almost at its original
thickness. On other cellos he strengthens the higher register to
make them brighter, on those bridges he sands away more, starting
the sanding below the the heart of the bridge. So finally all
bridges have a thickness of about 2.5mm where the strings cross
them, but if you look at the bridges from the side, the curvature of
their thickness differs. That is why I think that an experienced
luthier can optimze the sound better than I ever could. I have only
played 2 cellos in my whole life, and I have problems to say whether
they are on the bright or dark side. Because this
bridge-optimization-process requires that you put the bridge on the
cello and remove it many times, he uses a tool to keep the strings
and the soundpost tensed. It is a dummy bridge with a screw that
allows to change its height quickly. When he removes the real
bridge, this dummy bridge is inserted and adjusted a bit higher than
the real bridge, so the real bridge can be removed almost
tension-free without scratching the cello's top. Re-inserting the
real bridge works the opposite way, so changing bridges is a matter
of a minute. Without that tool it will take you hours, making the
comparison between the changes in sound difficult... good luck,
please keep us informed whether the sound has
improved.
Horst
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