Just a few thoughts that have been rattling around in my head this
morning....
On instruments with tailpieces/combs/hitchpins and a floating bridge, you
have to deal with some design trade-offs, such as: breakover angle; string
after-length; neck angle; and downward pressure on the soundboard
system...as well as the usual bridge movements due to plucking/bowing. The
downward pressure problem in those instruments is often countered through
strengthening the soundboard by: cambering (citterns); arching
(violins/gambas); cranking (as in Neapolitan mandolins); or by using a
tensioned flexible membrane instead of a soundboard (banjos). Glued bridges
and floating bridges also don't work exactly the same...without altering the
shape of the instrument to accommodate the downward push of the strings and
the additional up/down motion of the bridge (when using
afterlength/tailpieces/combs, etc.), a floating bridge doesn't work very
well.
While I'm obviously not a physicist, I've been around luthiery, traditional
woodworking, and bowyery for a few years now. I suspect the lute's lack of
string afterlength/tailpieces has partly to do with the efficiency of all
the coupled systems in the lute. Floating bridges, tailpieces, extra string
length, etc., add mass to a system that might not tolerate the additional
mass very well. If you look at many instruments with tailpieces/ string
afterlength, they often either require constant input from a bow or wheel
to keep the string vibrating (gambas, violins, etc.), or are plectrum
instruments that were adapted to have a sharp attack and fast decay
(citterns, banjos, etc.). Also, string afterlength and tailpieces have
additional resonant frequencies that can either kill sustain or deaden notes
on the instrument through sympathetic vibration.
Altering the shape of the soundboard by slightly scooping along its length
may also slightly change how the string energy is transmitted through the
soundboard (or at least how the soundboard reacts to that energy). When a
soundboard is flat, some of the energy from the strings has to fight against
wood in compression. Adding the scoop may change how much of the vibrating
energy is fighting against compression, by forcing some of the wood to be in
tension...changing how torque from the string/bridge and soundboard affect
each other.
Another consideration might be just how the soundboard responds to the
bridge/string in a scooped top. Does the scooped top rebound from
longitudinal torque/flexing faster, slower (or the same) as the flat one?
Ron Banks
Fort Worth, Texas
-----Original Message-----
From: lute-...@cs.dartmouth.edu <lute-...@cs.dartmouth.edu> On Behalf Of
ido66667
Sent: Sunday, June 30, 2019 10:09 AM
To: lutelist Net <lute@cs.dartmouth.edu>
Subject: [LUTE] Re: Plucking Room
I don't think the main reason is the lack of frets. Fretless acoustic
guitars, nylon strings or not, are both fretless and plucked and their
sound is decent, both with regards to tone and sustain.
On Sun, 30 Jun 2019, 16:59 Miles Dempster,
<[1]miles.demps...@gmail.com> wrote:
Violins, violas etc. don't have frets. When plucked (rather than
bowed) the string vibration is dampened by the soft fingertip at the
stopped end. I don't think that the sustain depends significantly on
how the bridge connects to the soundboard.
Miles
> On Jun 30, 2019, at 9:01 AM, Edward Mast
<[2]nedma...@new-old-mail.cs.dartmouth.edu> wrote:
>
> A good question, Dr. Mardinly. What one notices, though, is that
when violins, violas, cellos and string basses have their strings
plucked rather than bowed, the sustain of the note is short (string
basses doing by far the best, and violins doing the worst with
pizzicato - plucked notes). It thus seems to me that the method of
having the strings stretched over a non-fixed bridge as they are for
the bowed instruments, works very well for transmitting the
vibrations of the strings to the instrument when they are bowed, and
not so well at all when they're plucked. The fixed bridges with
strings attached as on guitars, lutes, etc. seems to be the best way
of transmitting the vibrations to the instrument when the strings
are plucked, rather than bowed.
> A luthier's explanation of this would be welcome.
> Ned
>
>> On Jun 29, 2019, at 3:50 PM, John Mardinly
<[3]john.mardi...@asu.edu> wrote:
>>
>> Spot on explanation of what physics does to sound boards. The big
question that I have never had answered is why do plucked string
instruments have the string tension carried by the soundboard
itself, instead of having the string tension carried by the body of
the instrument via a tailpiece the way violins, violas, cellos and
string basses do?
>>
>> A. John Mardinly, Ph.D., P.E.
>>
>>
>>
>>
>>
>
>
>
>
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--
References
1. mailto:miles.demps...@gmail.com
2. mailto:nedma...@new-old-mail.cs.dartmouth.edu
3. mailto:john.mardi...@asu.edu
4. http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
