In fact both lute and guitar bridges function in the same way. In
short, a horizontal force (imposed by the string) is momentarily
increased when the string is displaced (plucked); this in turn
increases the turning moment of the bridge (ie force x height of string
above belly at take-off point) which in turn causes the belly to
vibrate with mostly a wave action (tho' some vertical pumping action
too) and thus amplifying the sound by varying the air pressure within
the soundbox. Whether the vibrating string leads from a loop (lute) or
from over a saddle (later guitars) is immaterial - it is the height of
the string at take-off which is relevant. Vibration patterns have, in
fact, been studied: eg the Galpin Society Journal (Hellwig I recall)
which contains relevant papers.
Differences in timbre between instruments may well be due to many other
factors rather than the way the physics of the bridge works, including:
mass of bridge (size and density), surface area of base of bridge,
stiffness of bridge, barring, internal shape of soundbox and its
volume, etc.
An illustrative example: many years ago I made a 5 course guitar after
Sellas and fitted an ebony bridge (thinking the original had one). The
sound was quiet and muffled (tho' with considerable sustain). I had a
rethink and after further investigation decided to remove it and fit a
fruitwood (actually pear) black stained bridge to precisely the same
design: the resulting sound was considerably freer and increased the
output ie volume. In fact the much greater mass of the ebony bridge was
acting as a considerable dampener requiring more of the vibrational
energy of the string to set it in motion than that of the fruitwood
bridge which had a mass less than half that of the ebony. On the other
hand, the ebony bridge's greater mass meant that it had more inertia
and thus continued to oscillate for longer than the fruitwood bridge -
thus giving the greater (if much quieter) sustain.
MH
PS Incidentally, drilling the string holes low down on a modern guitar
bridge does not increase the string tension/force and hence the turning
moment of the string at the bridge (and it could not be otherwise,
since for a given string the pitch is simply a function of transverse
force/string tension) but does increase the resultant vector
downbearing on the saddle which avoids excessive frictional string
slide (and hence loss of energy ie output) across the saddle. The
discrete loop take-off point used on lutes and early guitars avoids
this problem.
__________________________________________________________________
From: "[email protected]" <[email protected]>
To: lute-cs.dartmouth.edu <[email protected]>; Bruno Correia
<[email protected]>
Sent: Friday, 1 August 2014, 1:18
Subject: [LUTE] Re: Lute Bridge vs Guitar Bridge Functioning
Thanks Bruno! So far, yours is the only response.
I hope to hear some more also : )
Tom
Date sent: Sat, 26 Jul 2014 18:57:28 -0300
To: "lute-cs.dartmouth.edu" <[1][email protected]>
From: Bruno Correia <[2][email protected]>
Subject: [LUTE] Re: Lute Bridge vs Guitar Bridge Functioning
Very nice question! Hope to hear some responses on this topic.
2014-07-26 11:20 GMT-03:00 <[1][3][email protected]>:
Dear List,
A I have always assumed that a lute bridge moves / vibrates in a
different manner than a guitar bridge, and that this, plus the
bracing, etc. mainly account for the difference in timbre between
the two different instruments - that the strings of a lute exert
force in a plane parallel to the belly, while the saddle of a
guitar bridge creates "downbearing" or force perpendicular to the
belly, causing more of a rocking motion. A Following this line of
reasoning anything on top of a lute bridge would be primarily
decorative. A But - could a luthier angle the string holes in a
lute bridge at about 30 degrees to create a downbearing-like
function? A Would that have any positive or negative impact on
lute tone or projection? A Am I correct in this assumption, or
way out in left field? BTW, has anybody done vibration pattern
imaging on lute bellies similar to the what has been done in
violin research? A Looking forward to your responses, A A
Thanks, Tom Draughon Heartistry Music
[2][4]http://www.heartistry.com Date sent: A A A A A A A Sat,
26 Jul 2014 15:27:26 +0200 To: A A A A A A A A A A
"[3]lute-cs.dartmouth.edu" <[4][5][email protected]> From: A A
A A A A A A A Anthony Hind
<[5][6][email protected]> Subject: A A A A A A A A
[LUTE] Re: Lute bridge Dear Bruno Looking at the instruments of
the CitA(c) de la Musique seems to show that ivory or bone on the
bridge goes together with the same decorations on the fingerboard
and elsewhere, [6][7]http://tinyurl.com/nlvpy32 Thus unlikely to be
acoustic in intention. Regards Anthony Sent from my iPhone > On
26 juil. 2014, at 00:32, Bruno Correia <[7][8][email protected]>
> wrote: > > Dear Daniel, > This thin slice of bone is precisely
what I was referring to. I'm > sure you have seen many lutes with
these cap. All the best. > 2014-07-25 18:44 GMT-03:00 Dan Winheld
<[1][8][9][email protected]>: > > A Never had a bone on any of my
lute bridges (except the guitar > A saddle bone on my first
guitary-semi-lute). I have never seen a > A bone on any lute
bridge either. A thin slice of bone, ivory, or > A hard wood
seems like a good idea to limit string wear on the top > A edges
of a bridge, so long as it does not increase mass to the > A
extent of degrading the sound. Of course, as a player & not a > A
luthier I'm sure I haven't all the lutes out there. Maybe some >
A Tielke extravaganza has bone or ivory bridge decoration. What
> A particular lutes have you seen with this feature? Any
pictures? > A Dan > > -- > Bruno Figueiredo > A > Pesquisador
autA'nomo da prA!tica e interpretaAS:A-L-o > historicamente
informada no alaA-ode e teorba. > Doutor em PrA!ticas
InterpretativasA pela > Universidade Federal do Estado do Rio de
Janeiro. > > -- > > References > > 1.
mailto:[9][10][email protected]
> > > To get on or off this list see list information at >
[10][11]http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html Tom
Draughon Heartistry Music
[11][12]http://www.heartistrymusic.com/artists_tom.html 714 A 9th
Avenue West Ashland, WI A 54806 [12]715-682-9362
--
Bruno Figueiredo
A
Pesquisador autA'nomo da prA!tica e interpretaAS:A-L-o
historicamente informada no alaA-ode e teorba.
Doutor em PrA!ticas InterpretativasA pela
Universidade Federal do Estado do Rio de Janeiro.
--
References
1. mailto:[13][email protected]
2. [14]http://www.heartistry.com/
3. [15]http://lute-cs.dartmouth.edu/
4. mailto:[16][email protected]
5. mailto:[17][email protected]
6. [18]http://tinyurl.com/nlvpy32
7. mailto:[19][email protected]
8. mailto:[20][email protected]
9. mailto:[21][email protected]
10. [22]http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
11. [23]http://www.heartistrymusic.com/artists_tom.html
12. tel:715-682-9362
Tom Draughon
Heartistry Music
[24]http://www.heartistrymusic.com/artists_tom.html
714 9th Avenue West
Ashland, WI 54806
715-682-9362
--
References
1. mailto:[email protected]
2. mailto:[email protected]
3. mailto:[email protected]
4. http://www.heartistry.com/
5. mailto:[email protected]
6. mailto:[email protected]
7. http://tinyurl.com/nlvpy32
8. mailto:[email protected]
9. mailto:[email protected]
10. mailto:[email protected]
11. http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
12. http://www.heartistrymusic.com/artists_tom.html
13. mailto:[email protected]
14. http://www.heartistry.com/
15. http://lute-cs.dartmouth.edu/
16. mailto:[email protected]
17. mailto:[email protected]
18. http://tinyurl.com/nlvpy32
19. mailto:[email protected]
20. mailto:[email protected]
21. mailto:[email protected]
22. http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
23. http://www.heartistrymusic.com/artists_tom.html
24. http://www.heartistrymusic.com/artists_tom.html
