h a l f b a k e r yTrying to contain nuts.
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Strappado refers to the torture scheme whereby an unlucky individual is hung by their arms and weights are attached to their feet and the whole thing feels horrible for the person.
The stappaodlin relies on a similar arrangement, but nobody is tortured. Finely wound steel strings are hung by their
"arms" from a rafter mounted 15 feet high, and different weights are attached to the different strings "feet", providing ample tension. Now, when the strings are stroked they make their ever soothing sounds. It is expected that this would not sound anything like a harp, or a guitar, piano, or anything of the sort.
Weighted Strings. A pendulum passes a magnet, with mechanical vibrations.
http://www.neilfeat...eighted_strings.htm
With sound clip. Wow! I'm in Ambient heaven! [Amos Kito, Apr 18 2008]
Vincenzo Galilei
http://galileo.rice.edu/fam/vincenzo.html
Performed experiments on lengths and tension of strings on weights. He's said to have had a "room full" of such strings. [Amos Kito, Apr 19 2008]
Strike a Chord: Pizzicato Piano
http://www.questaco...pizzicato_piano.rtf
with equations! [Amos Kito, Apr 20 2008]
The Earth Harp: World's Largest Stringed Instrument
http://youtube.com/watch?v=lv26V1orb0Q
Not plucked. The strings are rosin rubbed. [Amos Kito, Apr 20 2008]
[link]
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Ah. I was thinking this involved tuned prisoners. |
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how is this pronounced? I read it as "strap it all in" |
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Stress the second and fourth syllables, and you should be fine. |
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Envision each weight being shared by two wires. The wires are attached at opposite ends of the ceiling so the affair forms a letter V. Several are arranged in parallel. The weights are round steel balls. This is now like the executive toy where one ball swings to hit the next, and the wave goes back and forth. By using wires instead of string and affixing the wire in a way to minimize dampening, the wires should vibrate on each strike, and the apparatus play a series of notes forwards and backwards, |
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Admittedly, you can really just about envision anything with simply weights and wires. I would also like to see smaller wires and smaller weights attached to the ends of the larger original weights, which may account for octaves and tonal variety.
You are on the hoped for track, bungston. There's no reason we can't stack these arrangements all the way up. |
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This would be a swell museum exhibit. One could play these wires by whacking the weights with a big gnarly mallet. |
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Erm, it's going to need a sounding board of some sort, or it's going to be very quiet. Which may be why the Spanish Inquisition stayed with the old version. |
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Clarke's "Songs of Distant Earth" described the musical qualities of the space elevator. The cable extended from the planet surface to the space craft, with atmospheric effects causing beautiful sounds. That's a much longer version of this idea. |
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This would have unimagineable bass quality. |
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The sounding board could be on the ceiling. Could be the ceiling. |
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It sounds like you are all way over thinking this. I think it's a mandoline with special straps that keep it from coming off while bungie jumping. |
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This would be a gnarly wind chime. |
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Just where is that gnarly wind when you need it the most... |
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Bellowing through the gnarly plains? I'm glad the voting bakers still fancy a simple physics based idea.. The part I like best about this idea is that, no matter how hard I try I can't figure out what this would sound like, but in my head there is a strongly reverberating vibrato that seems to make sense. |
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This is a great idea in all respects except
feasibility. |
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Daseva, did you stop to calculate the
tension you will need in a 15-foot string
to produce an audible note? |
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[daseva], you ought to ask Galileo's dad. [Link] |
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Great Links. Max, who has time to calculate? I'll leave that to the interns. Anyways, the second link kinda bakes this, so it's gotta be possible. |
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//Great Links. Max, who has time to
calculate? // The people
who have time to calculate are the
people
who make things that work (although
the same people generally don't have to
do the calculations to see the flaw). |
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Yes, mister
Galilei had a room full of weighted
strings.
He used them because they vibrated
slow
enough to see them moving. |
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You are about to produce a musical
instrument audible only to elephants.
Calculate. |
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It's not beyond my comprehension that something out there can vibrate thousands of times per second without disrupting the gravitationally balanced forces contained therein. I don't understand why you are so demanding at this point. Calcs will be produced, as per your request. |
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Go for it. Gravitation has nothing to do
with it, other than providing the
tension. What you're up against here is
physics and reality, alas. If your strings
are on the order of 15ft long, you'll
need a huge tension to make their
resonant frequency high enough to
hear. To enable them to take this
tension, they will need to be very strong
which, unless you use unobtainium,
means that they have to be quite thick.
Sadly, this means that their mass is
greater, which means that the tension
has to be higher still....you're on a
losing battle. |
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I'm not demanding calculations - I'm
just trying to point out that you need to
engage with reality a little and that,
sadly, this won't work. |
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Harmonics. Far back in my wild youth, I found that a fishing line on a hook screwed to a wall outside a house could set up a vibration heard through the entire structure. Pull your fingers down the line, to make the eerie noises. The line could easily be 200 feet long, and dropped to the ground when someone looked out a window. Per [Link], the Earth Harp turns this effect into performance art, with strings five times longer. |
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//You are about to produce a musical instrument audible only to elephants.// ...so change the title. |
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[Amos] Yes indeed, but those are
longitudinal oscillations, not harmonics
of a transverse (harp-like) oscillation. |
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[Daseva] Some simple calculations. The
frequency of a string is given by: |
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where L is the length in metres, T the
tension in Newtons, and u the mass per
unit length. |
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So, let's assume you have a 5 metre
string with a cross-section of 0.25
square millimetres, of high-tensile
steel. It will support a
load of about 500N, and will have a
mass of about 0.002kg/m. Hence,
when supporting its maximum load, it
will have a natural frequency of 50Hz.
Of course you can make the wire
thicker, enabling it to support more
load, but then its mass per unit length
increases proportionately and cancels
out. |
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Of course, it will have harmonics, but a
string with a weighted (and hence
somewhat free) end will not support
harmonics to any great degree. |
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So, you are going to be building a large
device for replicating mains-frequency
hum. |
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We just need carbon nano-strings. |
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If you use Kevlar, you might be able to get
up to about 120Hz. Unfortunately, its
lower density means it'll carry less kinetic
energy when you pluck it, so it'll be a fairly
quiet low hum. |
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// You are about to produce a musical instrument audible only to elephants. Calculate.
MaxwellBuchanan, Apr 19 2008//
The elephants might like it. |
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It appears string material and rafter height might be the main points holding this idea back. That and neglecting elephants' musical taste. |
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If you added a smaller weight half way along the string, would it double the frequency? If so, could you add weights to divide the string up into 1/4s, 1/8s, etc? Does that only work with relatively slack strings where the force required to move the string is much less than that required to move the weight? I know very little about such things. |
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Yes, you can have a weight at any point on
the string; the pitch will then be (more or
less) what you'd expect from the shorter
length of string between the two weights.
But then this becomes a complicated way
of making a regular harp. |
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I say build it for the elephants. |
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You are saying I can't hang a five pound weight from a rubber band, pluck said band, and hear the note? |
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I would go prove you wrong if it were not such a ridiculous assertion. |
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No, [getlunch], I am not saying that. |
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What I said (in words) is that if you have a
15-foot string, you just can't stretch it
tight enough to make anything except a
very low pitch, before it snaps from the
tension. |
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This may help--note the length. "Hanging a B-string from a nail over [a] door, we clamped it at the free end approximately 640 mm from the nail and hung one of our our mail bags off the clamp: Filling the mailbag . . . to a total weight of approximately 8kg, we proceeded to pluck the string and lo and behold a sound not too far from a B was heard." |
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So yes, that worked , but notice that the length was that of a guitar neck, about two feet. As [MaxB] keeps trying to tell you, this idea description specifies 15 feet, and that length would make a super-low note at any achievable tension. |
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Longer is lower, bigger is deeper, heavier is slower. A fifteen-foot string is going to be too low to hear, at any tension that it can take. If you make it thicker, for more strength, it gets heavier, and vibrates slower. It can't work as described--the gods forbid it. A smaller, shorter strappadolin could be made to work, yes. (But it would sound like any other stringed instrument.) |
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Consider this: There is nothing stopping folks from making giant fifteen-foot versions of normal stringed instruments--with frames, bodies and all--or mutant art projects, is there? Except the fact that they wouldn't play anything humans could hear. This is one of those things that isn't being done because it won't work. |
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That Earth Harp (that video was icky) is played by pulling along the length of the string, as [Amos Kito] describes with his fish line. The Strappadolin may be played that way, but the description doesn't say that, it just says "stroked". |
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If it were intended to be played by pulling down along the rosined strings, it would work, [MaxB]'s objections would no longer apply, and it would sound strange. But it would probably not need to be fifteen feet long, and nothing would be gained by having weights instead of a lower frame for tension. (And it would be a lot like an old "panther call" which is a rosined string through a drumhead.) |
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This is one of those things that are just confusingly different enough to seem possible, and vaguely-enough described that folks fill in the blanks in their minds. Then they jump all over the scientist who tries to show the truth. (Sorry, I've been reading Richard Dawkins about religions.) |
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I agree. Let's not get plucking fixated. If pizzicato is essential to the idea, have a mic pickup and sound processor (to convert the signal to audible tones). |
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If you're inventing a surreal instrument, high wind passing the strings would make interesting noises. And the rosin-stroked harp or mechanical vibe [Links] are still more ways the Strappadolin could work. |
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Actually, only the height of the rafters is specified, not the length of the strings. Perhaps they range from short high notes, all the way down to the elephant levels, providing an immense range of pitches to the accomplished strappadolist. Perhaps a rolling stepladder of the type utilized in awesome old libraries is involved. |
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