Any ideas for science fair project using the harp?

[Tacye]

To what accuracy (percentage and or absolute) do you need the tension on each string?

[carl-swanson]

Tacye- I don’t have any figures at all and I don’t know anyone who does. That makes this a gaping hole in the understanding of the harp. All of the harp makers are basically making seat-of-the-pants decisions about soundboard thickness, string gauge, etc. without any hard facts. And new products, like carbon fiber strings, are being introduced without anyone knowing how much additional stress they are causing the soundboard and neck. Ursula Holliger told me this past weekend that she has been measuring the thickness of the strings she has been using for the last 40 years, and the strings just keep getting thicker and thicker.

Maybe the first step is to do mathematical calculations on a sampling of strings, and then check the answer against a test on a monochord to see if they match. If they do, then the equation works. If not, then it needs to be reexamined and fiddled with until it does.

Thank you for the offer. I really appreciate it. I’d love to pursue this further.

[patricia-jaeger]

Somewhat related to the effect that sound vibrations would have on colored beads: Carleen Maley Hutchins, who died just last year at age 98, became a well known maker, or luthier, of bowed stringed instruments. In an article in Scientific American, October 1981 she described how she picked the best tonewood for her instruments by means of small metal particles sprinkled like sand on the wood, and then with various tones played, the particles would jump and disperse themselves on the wood, forming patterns. With words and pictures she described how this helped her to choose the most resonant wood for her violins, cellos, etc. She received four honorary doctorates and was received into several prestigious acoustics and physics societies, not only for the procedure described here, but for the excellence of her research and the resulting superior tone of the instruments that she made.

[Elizabeth Volpé Bligh]

Dear Tayce,

I did not know you were a physicist! Dr. Chris Waltham is another physicist who loves the harp, and he is presenting his research paper on soundboards at the 11th World Harp Congress, along with his colleagues François Gautier and Jean-Loïc Le Carrou. He lives in Vancouver and teaches at UBC.

[Tacye]

I don’t know Chris Waltham personally, but am aware of some of his papers on harps- and referred Carl to some of his data above.

Carl, have a think about how accurate you want the figures.

[carl-swanson]

What does BB refer to? Bow Brand? Your question makes me curious as to how consistent testing these strings on a monochord would be. In other words, If I tested 4 gut 4th octave C strings on a monochord, would I get, within a pound or so, the same reading for all 4 strings?

It seems to me that a variation of 2 to 3 kilos(approximately 4 to 6 pounds) is quite a lot. Multiply that by 47 and you’ve got a significant range in overall tension on the instrument. If I wanted for example to compare the variation in tension between 2 4th octave C strings, one being standard gauge and the other thinner by .006 inches, and the margin of error was 4 to 6 pounds, then the information would be useless. This is why I keep coming back to the monochord. I would be able to see, to the ounce, what the tension was.

[Tacye]

Yes Carl, the error margin I gave is large- this is because I was estimating in only a minute or two with dodgy data.

[carl-swanson]

Tayce- I just had a thought. I’m wondering if I could make up a jig that would have a scale on it that could be clamped onto the neck of a harp. The string to be measured, right on the instrument, would bypass the tuning pin and be hooked instead onto a scale on the jig. A tuning pin on the jig, connected to the scale which was connected to the string, would then do the tuning. The string tension would then be measured right where it is on the instrument and under exactly the same conditions. Now, can you suggest some kind of scale that is as short as possible? Maybe 3 or 4 inches long, with a hook on one end and something to anchor it at the other?

[Tacye]

Something like this?
http://cgi.ebay.co.uk/Digital-Luggage-Weighing-Scale-40kg-inc-batteries-/170542981039?pt=UK_TravelTickets_Accessories_RL&hash=item27b5275faf

[carl-swanson]

Yeh, but I’m worried that the 40K limit may not be enough for the longer gut strings and wires. When I have a minute I’ll look around on the internet and try to find something.

[kay-lister]

Mary, I just found another goodie on you tube.

[bill-and-jennifer-jenkins]

Coming to the conversation late, but have you ever looked at a vibrating harp string with a TV screen behind it?

[John McK]

I think it’d be useful to just

a) get a harp set up with nylon strings and plug it into an oscilloscope to a readout of the strengths of various harmonics within a sample note or two (say, middle C)

b) get the same model of harp, same note, but use a different type of string, and repeat the measurement.

This would be cool stuff – it would show, scientifically, numerical data that explains why gut & nylon strings sound different.

Getting into other areas, you could do an experiment related to temperaments.

– Tune the harp to equal temperament
– Play a piece (or get someone to play a piece) to an audience

– Re-tune the harp to Pythagorean tuning
– Play the same piece to a similar audience

– See if you can measure any difference in subjective enjoyment of the piece of music.

The point would be to test the appeal of different temperaments, so it would be more of a psychology experiment than a physics experiment.

[harp guy]

I don’t know what that would necessarily show though. I think different harps react differently with different strings. A friend of mine had a Troub III (originally in nylon) and switched to gut and the sound became richer (as expected). I have a Prelude 38 and just switched to all nylon and the sound became more mellow, and I thought it would have gotten brighter. It did become less resonant as expected, but the sound became darker (which I really liked).

So I think such an experiment would show results for that specific harp, but I think it would be almost as if trying to prove exactly what different woods do to the sound of the instrument (which is still inconclusive).

If it were a study done across a few hundred harps, I think it would have some merit.

[Ayren Huslig]

This is way too late and easy, but I had a middle school student do this for a science project once and it cracked me up so I thought I would share it.

[Author]

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