GermanHarpist
362 posts
May 30, 2009
3:35 PM
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...unfortunately only in german.
This guy invented an electronic harmonica, a heated harmonica box, and analysed quite a lot of the harmonica physics (1,2,3).
and some other neat stuff.
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germanharpist, harpfriends on Youtube
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Tryharp
191 posts
May 30, 2009
3:51 PM
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Hey GH,
That looks really interesting, although I cant read German. I like the finite element alanysis on page 2, I have done this for structures before. If you have time to translate a bit, were there any key findings or surprises from the study.
Thanks
Tryharp
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Tryharp
192 posts
May 30, 2009
4:38 PM
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Thanks Gorignak,
I'll give it a go.
Tryharp
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GermanHarpist
365 posts
May 30, 2009
5:05 PM
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Yes, one thing: So, he sais, and it sounds credible, it is not the vibration of the reed that creates the sound... if you think of it (the only sound created by the vibration of the reed is the sound when you plinker). It is actually the air (that you draw through the harp) that is chopped up by the vibration of the reed. This creates periodical pressure variations, that reach our ear as sound. He found that out using a stroboscope, he matched the position of the reed with the pressure of the sound wave.
It's all in the third link. If you click the little pictures, he actually filmed the vibration of the reeds in slow mo..!
The first, but especially the second link is nothing new, but very interesting. The FM stuff is awesome! Again you can click the pictures to see it animated.
The electronically amplified harp is also very cool geek stuff (but not really usable in real life). He actually instally 20 instruments in the harp for each reed. They measure the distance of the reed and create an electronic signal. The principle explained in the previous point is the greatest weakness of the harp. As you may have noticed on some harps, also if you stop drawing the reed keeps on vibrating. Well, that is also amplified with his e-harp. Another thing is that the instruments get distorted when they get wet and the signal is not so good because there are so many instruments connected in a row.
The heated harp box is pretty self explanitory. He kinda puts a lot of importance on preheating harps. So he build this box (that has to be connected to a normal electricity plug).
Then he also developed (count them) three harp charts. The first shows the notes on each hole for each harp, the second is all the modes and the third, I don't really understand. But it looks like some pretty crazy stuff. You can print them all out with .pdf and build it yourself.
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germanharpist, harpfriends on Youtube
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Tryharp
193 posts
May 30, 2009
5:41 PM
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Thanks for post, and the summary GH, interesting stuff.
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GermanHarpist
366 posts
May 30, 2009
6:14 PM
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...yes, it really is.
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germanharpist, harpfriends on Youtube
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MrVerylongusername
337 posts
May 31, 2009
11:21 AM
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Very interesting There are no new discoveries about reed action here, but it is really great to actually see it in action. Those slow-mo clips are wonderful. This stuff has been known for a long time, but this site has made it very accessible.
A lot of chrom players heat their harps before a performance. It stops the valves jamming and breath condensing on the reeds.
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nacoran
31 posts
May 31, 2009
12:02 PM
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Anyone else notice that the translation reads almost like some weird porn that you can't quite understand?
Cool though.
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ZackPomerleau
120 posts
Jun 01, 2009
5:30 AM
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Maybe, just maybe, you watch way too much weird, translated porn?
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STME58
60 posts
Dec 19, 2011
11:39 PM
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I was doing some research into vibrating reeds, trying to understand how an overblow works, and came across this old thread. I measured a 7 bloow reed on a seydel LowD harp and modeled it in FEA.
I got the following resonant frequencies.
Mode Frequency [Hz]
1 305.083
2 1909.83
3 3359.53
4 5360.08
5 8382
6 10250.2
7 10546.2
8 17509.8
9 17637.7
The first mode is not far of from the 293.66HZ the reed shoud sound at if it is an in tune D so the model is somewhat close. The second mode is nearly 2 octaves up form the fundemental so I dont think these are activated in normal playing.
Here are some .avi files of the mode shapes. After 3 years the FEA software is probably easier to use but the results are similar to the german web posting.
http://dl.dropbox.com/u/52636345/Mode1.avi
http://dl.dropbox.com/u/52636345/Mode2.avi
http://dl.dropbox.com/u/52636345/Mode3.avi
http://dl.dropbox.com/u/52636345/Mode4.avi
http://dl.dropbox.com/u/52636345/Mode5.avi
Is anyone aware of any current research on this?
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