Is the Earth Harp real (acoustically)?

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In summary, the conversation discusses the authenticity of the "Earth Harp" instrument, which was featured on "America's Got Talent" and is played by musician William Close. The person questioning its legitimacy has a background in music composition and acoustics and raises several points about the instrument's design and performance. They believe that the strings are not properly tensioned and that the sound is likely triggered by a hidden mechanism. However, another person points out flaws in their reasoning and suggests that the instrument may still be real despite these concerns. The conversation ends with the questioner seeking others' thoughts and opinions on the Earth Harp.
  • #1
Jiminy
Is the "Earth Harp" real (acoustically)?

Has anyone seen this "Earth Harp" guy on TV? He was on "America's Got Talent" a few weeks ago, and I am highly doubtful that this instrument is real. I have a degree in music composition, and I've got several unit of forma instrument acoustics study, not to mention having a firm basis in instruments so I can competently compose for them.

I would like to give a couple of links for reference, but I'm new here and the forum software will not allow it. He has a website and a number of videos on YouTube. His name is William Close, and the name of the instrument is "Earth Harp".

The red flags for me that this is not an acoustical instrument are (in no meaningful order):

1) You can see the strings vibrating. In fact, you can see them wobbling. If discrete vibrations are slow enough to be seen (the resolution of human eye maxing out at about 30 "frames" per second), those vibrations are going to be very low — much lower than the ones he's playing, and if they're lower than about 20 Hz, they're not going to be audible at all.

2) All string instruments require strings which are plenty tight. A wobbly string is just not going to sound.

3) If they the strings were mounted and tensioned properly, and even if they did wake a periodic sound wave, the length and mass of these strings is such that they would, again, vibrate to slowly to be audible.

4) The tension necessary to make such long strings vibrate musically would be considerable to say the least, yet in the guy's booking info page, he lists 6 to 8 small bolts as being all that's necessary for mounting the "sound board" to the stage.

5) Playing a string musically typically requires a displacement that is perpendicular to the string — whether it's bowed, plucked, strummed, or hammered. These create transverse waves. When you hear a beginner violin student play those squeaky tones, he's doing it because his bow is not perfectly perpendicular to the string, so in addition to the transverse waves, he's also producing some longitudinal waves as well. These l-waves are what cause the annoying high-pitched squeaks. Yet the Earth harp guy claims that longitudinal waves are exactly his instrument produces. A slinky is a real world example of something that can vibrate entirely longitudinally.

6) His manner of playing the strings is by rubbing them down their length, again, rather than perpendicularly. I may be drawing a blank, but I can't think of any string instruments so activated. The closes analog I can think of is percussion instrument called a "Lion's Roar", or sometimes just generically it is called a string drum. But these don't sound anything like the instrument in the video, and they use cloth strings, not metal. Moreover, as the fingers are drawn along the length of the Lion's Roar, the indefinite pitch slides in pitch the closer the hand gets to the drum itself. The pitch of the notes on the Earth harp does not change. If the general mechanics of the vibration are the same, the pitch should change, as fas as I can see.

7) On this guy's website, he says that people in the audience claim a wonderful experience when they are in the middle of the sound field created by the supposedly vibrating strings which are run overhead. But strings themselves don't make much sound at all. They transfer their energy to some sort of resonating body which is where the sound comes from. Even if this instrument did work, the sound would come from the sound box on the stage, not directly from the strings overhead.

8) He claims that these Earth harp "installations" turn the performing venue into the instrument itself. For example, when he mounts the strings across some canyon, he claims that the canyon is part of the instrument itself (and he doesn't mean that in the spiritual sense, but the physical one). I don't need to even get into how preposterous this is, much less the notion of playing strings that are stretched across a canyon.

9) On the faster part of the piece that he performs, the articulations are pretty responsive. But in real world acoustics, the larger the vibrating body, the slower it is to speak. That is why flutes are so light on their feet and articulate but contrabassoons are a bit clumsy and indistinct.

10) He's got these wooden blocks mounted to the strings (not mounted at the stopping ends, but mounted within what would be the vibrating body. He claims these blocks placed at different points are what tune the strings. But this can't be. The blocks do not rigidly stop off the string; they just hang there, and all they would do is to impede certain harmonic nodes of vibration, effectively killing the potential for any meaningful vibration. Any yet, the tones in the video are pretty rich in harmonics.

________________________________________

So, am I missing some sort of phenomenon of instrument acoustics, or is this instrument a fake?

My theory of how it actually works is that the pressure he puts on the strings triggers a midi event via some sort of custom mechanism concealed inside the "sound box" mounted on the stage.

Am I wrong? What are your thought about this Earth harp. thing? I'm not emotionally invested in wanting it to be fake, but either it is, or I'm really missing something here.

TIA
 
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  • #2


I don't know anything about the Earth Harp or its performances. But I can spot some errors in your logic. (Note this doesn't mean you're *wrong*, just that your reasoning is faulty)

Jiminy said:
1) You can see the strings vibrating. In fact, you can see them wobbling. If discrete vibrations are slow enough to be seen (the resolution of human eye maxing out at about 30 "frames" per second), those vibrations are going to be very low — much lower than the ones he's playing, and if they're lower than about 20 Hz, they're not going to be audible at all.
You are watching this on TV or on your computer or something, right? That introduces artifacts in periodic motion. The classic example is the "wagon wheel effect" (you should be able to google that).

I want to say you are observing the beat frequency between the actual vibration and the rate of the movie camera, but I'm not confident that's actually correct.
2) All string instruments require strings which are plenty tight. A wobbly string is just not going to sound.
Stringed instruments can vibrate quite visibly. It's been a long time, but the short time I played cello, I certainly remember being able to actually see the standing waves; they had an amplitude of a couple millimeters. The strings on a double bass can vibrate at even larger amplitudes.
3) If they the strings were mounted and tensioned properly, and even if they did wake a periodic sound wave, the length and mass of these strings is such that they would, again, vibrate to slowly to be audible.
Harmonics.
5) Playing a string musically typically requires a displacement that is perpendicular to the string — whether it's bowed, plucked, strummed, or hammered. These create transverse waves. When you hear a beginner violin student play those squeaky tones, he's doing it because his bow is not perfectly perpendicular to the string, so in addition to the transverse waves, he's also producing some longitudinal waves as well. These l-waves are what cause the annoying high-pitched squeaks. Yet the Earth harp guy claims that longitudinal waves are exactly his instrument produces. A slinky is a real world example of something that can vibrate entirely longitudinally.
If a tiny violin string gives a high-pitches squeak, then a very large string is going to 'squeak' in a more reasonable register.
10) He's got these wooden blocks mounted to the strings (not mounted at the stopping ends, but mounted within what would be the vibrating body. He claims these blocks placed at different points are what tune the strings. But this can't be. The blocks do not rigidly stop off the string; they just hang there, and all they would do is to impede certain harmonic nodes of vibration, effectively killing the potential for any meaningful vibration. Any yet, the tones in the video are pretty rich in harmonics.
When I played the cello, I often did this for fun.

Normally, if you draw the bow across the last string, you get A below middle C.

If you lightly touch your finger to the exact center of the string -- not enough to restrict it but just enough to prevent it from vibrating at that point -- then you get A above middle C.

If you do the same thing one third of the way along the string (or two thirds), you get the E above that, and so forth.The same effect is very important for woodwinds; you can't get high notes without this trick. But rather than block the things off, the mechanism to eliminate harmonics is to open a hole. This, for example, is the main purpose of the 'octave' key that controls the hole closest to the mouthpiece.

In fact, this knowledge was of at least a little help in devising my own fingerings for the very high notes on my clarinet (which helped because sometimes the standard fingerings don't come out strongly or are out of tune).
 
  • #3


Jiminy said:
6) His manner of playing the strings is by rubbing them down their length, again, rather than perpendicularly...

...So, am I missing some sort of phenomenon of instrument acoustics, or is this instrument a fake?
It's not a fake. You're missing the fact that rubbing the rods along their length is a perfectly legitimate way to get them to sound, and they don't even need to be stretched or attached at both ends to do this. The flopping of the rods, is, of course, not the source of the sound. They are vibrating at the proper cps just like a wine glass would vibrate when you run a wet finger along the rim.

edit: it looks the second time through that they are, in fact, attached at both ends. There are some weights which looked at first to be the ends, but I think the rods continue past the weights.

https://www.youtube.com/watch?v=nJUZGy26_Uk
 
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  • #4


How does the Earth Harp work? The Earth Harp is played using violin resin on cotton gloves and musical bows. The performer’s hands are run along the strings to created beautiful cello like tones. The act of rubbing the strings creates a longitudinal compression wave.

This vibration is similar to the vibration patterns that produce tones when you run your finger around the edge of a wine glass. It is also similar to the vibration patterns created while playing singing bowls.

As William Close experimented with some of his early design concepts, he created a method of tuning the giant long strings; using a specially designed tuning block that he discovered could tune the strings to any scale.

http://earthharp.wordpress.com/about/ [Broken]
 
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  • #5


Hurky, thanks for the reply!

Hurkyl said:
You are watching this on TV or on your computer or something, right? That introduces artifacts in periodic motion. The classic example is the "wagon wheel effect" (you should be able to google that).

It's not that kind of motion. It's not like plucking a guitar string and watching the cumulative effect of the very fast back and forth motion. There are many noticeable discrete vibrations and a lack of tightness one ordinarily needs to get a string to vibrate.

Hurkyl said:
Harmonics.

I don't see how it could be harmonics. Ordinarily when only the upper harmonics are audible, they still imply the fundamental. That's why you can perceive lower freqs on earbuds that cannot reproduce those freqs. And if the fundamental is below about 20 Hz, then they imply the first fundamental that is within the range of human hearing. And if the string were low enough to have a fundamental below 20 Hz, then it's going to sound really much thicker and more dissonant than the Earth harp, because you're already into the 7th harmonic before you even get to middle C.

Hurkyl said:
If a tiny violin string gives a high-pitches squeak, then a very large string is going to 'squeak' in a more reasonable register.

But the Earth harp notes are not uncontrolled squeaks; They're fully formed sustains. And the longitudinal artifacts occurring from beginner cellists and bassists are pretty ugly, too.


Hurkyl said:
When I played the cello, I often did this for fun. Normally, if you draw the bow across the last string, you get A below middle C. If you lightly touch your finger to the exact center of the string -- not enough to restrict it but just enough to prevent it from vibrating at that point -- then you get A above middle C. If you do the same thing one third of the way along the string (or two thirds), you get the E above that, and so forth.

The artificial harmonics you're talking about can only happen because the player's finger is stopping the string at a node, causing the string to vibrate in whatever multiple that node lies. The woodblocks just hang on the strings, but they're not attached to any sort of more rigid stopping body that would cause the string to vibrate in whole number divisions of itself — plus which the wooden block surrounds the string instead of just touching it.
 
  • #6


zoobyshoe said:
It's not a fake. You're missing the fact that rubbing the rods along their length is a perfectly legitimate way to get them to sound, and they don't even need to be stretched or attached at both ends to do this. The flopping of the rods, is, of course, not the source of the sound. They are vibrating at the proper cps just like a wine glass would vibrate when you run a wet finger along the rim.

edit: it looks the second time through that they are, in fact, attached at both ends. There are some weights which looked at first to be the ends, but I think the rods continue past the weights.

I'm not sure what you mean by "rods". He's supposedly making strings vibrate. Very long strings. Sometimes up to a 1000 feet, or sometimes just 30, or anything in between. And though the strings are of wildly varying lengths, according to each different installation, they always somehow manage to produce the same tone and in the same pitch region. Plus which, the acoustical properties of a resonant glass or Tibetan singing bowl are very different from the vibrating properties of a string. A string really wants to travel transversely.

The only way I've ever seen of making some sort of noise by rubbing a musical string longitudinally is by scraping a coin or guitar pick on a wound string, which of course is a decidedly different sound and effect.
 
  • #7


Hey again,

Yeah, I already read all that stuff from his website, but it gives no scientific basis for the acoustical chain. The gloves and the rosin could be stagecraft, or not, but they don't really give a basis that overcomes any of the red flags I mentioned. And I get the funny feeling that "longitudinal compression" wave was used to make it seem more scientific. "Compression wave" is just another term for longitudinal wave. People don't typically use both at the same time since they're redundant. He mentions the wine glass and prayer bowl, but strings do not behave like either of those.

I may look into whether he has a patent for this. Anyone know where to look for such info on the internet?

Anyway, thanks again.
 
  • #8
Jiminy said:
I'm not sure what you mean by "rods". He's supposedly making strings vibrate. Very long strings. Sometimes up to a 1000 feet, or sometimes just 30, or anything in between. And though the strings are of wildly varying lengths, according to each different installation, they always somehow manage to produce the same tone and in the same pitch region. Plus which, the acoustical properties of a resonant glass or Tibetan singing bowl are very different from the vibrating properties of a string. A string really wants to travel transversely.

The only way I've ever seen of making some sort of noise by rubbing a musical string longitudinally is by scraping a coin or guitar pick on a wound string, which of course is a decidedly different sound and effect.
Here you go, check out this video which demonstrates you can get a sound by rubbing along the length of a rod:

http://sciencestage.com/v/16539/singing-rod-a-cool-vibration-trick.html

I had seen this several years ago and assumed, at first, Close was using thin rods.
 
  • #9


In this demonstration they do a thing with a styrofoam cup that supposedly proves the vibrations are longitudinal as opposed to transverse:

https://www.youtube.com/watch?v=E4oMAfqtFZ4
 
  • #10


Zoobyshoe,

Thanks for the videos.

The problem is that the Earth harp does not use rods. It uses wire "strings". I've seen a lot of the videos and he's definitely using strings. Plus, I don't really see any practical way of him being able to get 1000 foot rods all the way to the canyon, or even how you'd get your hands on 1000 foot rods. That's more than three football fields.

And in the video you posted, the guy is holding the rod at the middle, the 2:1 node, creating the pure 2:1 harmonic. The Earth harp has strings which are mounted at each end, and the tones produced are more complex, and in spite of them being very long, they speak more quickly than the rod in the video — in fact, they articulate, rather than having the smooth, soft, onset of the rod. That throws instrument acoustics on its head.

And also notice that the rod is swiped nearly half of its entire length, whereas on the Earth harp, he swipes less than 10% of the length of the string. And In the canyon installation he'd be swiping less than 1%.

Another problem is that he changes direction when rubbing the strings. That's a disruption in the direction of compression, which should have some artifact, especially on such a long vibrating body.

Moreover, in the two rod videos, the hand has to leave the rod immediately after the swift swipe to allow the rod to vibrate, whereas with the Earth harp, the hands remain on the strings.

Anyway, so far I haven't been able to reproduce anything approaching a musical tone by repeating the same rubbing process on viola or piano strings.

At any rate, Zoobyshoe, I appreciate you taking the time to make these replies. I didn't know if anyone would be interested when I made my original post.
 
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  • #11


Jiminy said:
Zoobyshoe,

Thanks for the videos.

The problem is that the Earth harp does not use rods. It uses wire "strings". I've seen a lot of the videos and he's definitely using strings. Plus, I don't really see any practical way of him being able to get 1000 foot rods all the way to the canyon, or even how you'd get your hands on 1000 foot rods. That's more than three football fields.

And in the video you posted, the guy is holding the rod at the middle, the 2:1 node, creating the pure 2:1 harmonic. The Earth harp has strings which are mounted at each end, and the tones produced are more complex, and in spite of them being very long, they speak more quickly than the rod in the video — in fact, they articulate, rather than having the smooth, soft, onset of the rod. That throws instrument acoustics on its head.

And also notice that the rod is swiped nearly half of its entire length, whereas on the Earth harp, he swipes less than 10% of the length of the string. And In the canyon installation he'd be swiping less than 1%.

Another problem is that he changes direction when rubbing the strings. That's a disruption in the direction of compression, which should have some artifact, especially on such a long vibrating body.

Anyway, so far I haven't been able to reproduce anything approaching a musical tone by repeating the same rubbing process on viola or piano strings.

At any rate, Zoobyshoe, I appreciate you taking the time to make these replies. I didn't know if anyone would be interested when I made my original post.
You're quite welcome. I enjoy odd sound effects. I also still think this thing is perfectly plausible.

I don't think you'd be giving it a fair test unless you tried at least one long wire, say 15-20 feet. A roll of uncoated steel wire (not wound like a piano string, of course) of 20 feet can probably be got at the hardware store for a couple dollars. Maybe you can find a fence of some sort that has a corner so you can string it from one segment to the other. The other thing I am sure he's doing is electronically amplifying it.
 
  • #13


How the "earth harp" works.

The Earth Harp consists of a large tubular aluminum base unit that includes a "bridge" that is the ground level terminus for the roughly 16-20 heavy bronze strings. The bridge is a semi-circular box with an open front, aluminum frame and plywood surfaces that act as a resonant chamber. It is held down by sandbags. There are acoustic microphones set on top of this unit.

The strings are all pulled tight to roughly 30 pounds tension, but since they are played using the longitudinal standing waves, the tension is less important than the length, which they have predetermined mathematically and attached small wooden blocks at the appropriate place on the length of the string. (E.g., middle-C is 42 feet).
continued...

http://www.oriscus.com/columns/earthharp/
 
  • #14


Evo said:
Nothing is stranger than the theremin.

We are hijacking the thread, Evo will ban us.

 
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  • #15


Borek said:
We are hijacking the thread, Evo will ban us.



Is it a coincidence that those HANG instruments are shaped like flyer saucers?
 
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  • #16


Borek said:
We are hijacking the thread, Evo will ban us.

Hey, I went back on topic the very next post. :biggrin:
 
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  • #17


Let's not get too hung up about musicians not undestanding the physics of musical instruments very well. Even the great 19th century physicist Helmholtz managed to get the theory of brass instruments completely wrong, and held up the process of improving their design for several decades until somebody was brave enough to contradict him!

(The mistake survived for a long time because there was no way to check his theoretical assumptions by direct measurements, until electronic measuring devices were available).
 
  • #18


The strings are all pulled tight to roughly 30 pounds tension, but since they are played using the longitudinal standing waves, the tension is less important than the length, which they have predetermined mathematically and attached small wooden blocks at the appropriate place on the length of the string. (E.g., middle-C is 42 feet).
That's consistent with problems in the design of pianos caused by unwanted longitudinal vibrations of the bass strings "coloring" the sound of higher pitched notes. Middle C is about 262 Hz. The equivalent for a 8-foot-long wire would be 262 x 42/8 = about 1375 Hz, which is in the right ballpark for the problem frequencies with pianos. The speed of sound in most engineering metals is similar, so the different matierals aren't very significant.
 
  • #20


So this "Close" guy claims to have invented it eh? Seems it's been around for quite awhile.
 
  • #21


Evo said:
So this "Close" guy claims to have invented it eh? Seems it's been around for quite awhile.
The claim is he invented the first one in 1999:

http://earthharp.wordpress.com/about/ [Broken]
 
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  • #22


zoobyshoe said:
The claim is he invented the first one in 1999:

http://earthharp.wordpress.com/about/ [Broken]
Excellent find, explains even more.
 
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  • #23


From his website:

"The Earth Harp uses architecture and landscape as part of the instrument. The architecture becomes the instrument."

and

"It turned the valley into a giant harp!"

___________________________________

That is such a load of fertilizer.
 
  • #24


Jiminy said:
From his website:

"The Earth Harp uses architecture and landscape as part of the instrument. The architecture becomes the instrument."

and

"It turned the valley into a giant harp!"

___________________________________

That is such a load of fertilizer.

That is a bit of an exaggeration, but I think people know what he means. I think it's cool. If someone refuses to believe it's an actual instrument when it is, it's got to be awesome right!
 
  • #25


jreelawg said:
That is a bit of an exaggeration, but I think people know what he means. I think it's cool. If someone refuses to believe it's an actual instrument when it is, it's got to be awesome right!

According to responses I've seen to the video on YouTube, a number of people are buying into the marketing speak. People claiming the theater is actually like the sounding body of a guitar, stuff like that. You could claim that for ANY instrument that plays inside a reverberant hall, though it would be silly.

The jury is still out on whether it's real. So far no one here has presented anything that overcomes the long list of red flags I previously laid out.

And 1000 foot strings? Please. You're not going to rub a 1000 foot string and get any sort of instant response like the tones that are coming out of his "sound box".

The only reason to believe it's real at this point is faith and hope.

I've got some inquiries out to credentialed acousticians right now and will be interested to hear what they say. Would be illuminating to know why neither I nor any musicians I know can't come close to simulating anything like this with regular sized string instruments, despite trying various techniques. We've even used rosin, but maybe you need magic, New Age rosin made from ground up unicorn horns.
 
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  • #26


Jiminy said:
So far no one here has presented anything that overcomes the long list of red flags I previously laid out.
Eh? This ignores everything that has changed now about your assumptions.

Everything you assume about string vibration, tension, length, etc. becomes moot when the strings are treated as thin rods instead. Rods can, in fact, be vibrated in the way he claims for his strings. You'll have to start from scratch with new formulas about longitudinal waves in thin rods.

neither I nor any musicians I know can't come close to simulating anything like this with regular sized string instruments
Given the very high pitch of the aluminum rod in the video you ought to consider the tone produced by rubbing a common violin string this way might be ultrasonic.
 
  • #27


zoobyshoe said:
Eh? This ignores everything that has changed now about your assumptions.

Everything you assume about string vibration, tension, length, etc. becomes moot when the strings are treated as thin rods instead. Rods can, in fact, be vibrated in the way he claims for his strings. You'll have to start from scratch with new formulas about longitudinal waves in thin rods.Given the very high pitch of the aluminum rod in the video you ought to consider the tone produced by rubbing a common violin string this way might be ultrasonic.
Hi Zoobyshoe,

I haven't really made any assumptions about anything. I'm applying real-world acoustical principles, and I know for a fact that in the physical world, mass, resistance, amplitude envelope and frequency are inextricably linked, no matter what sort of wave you're talking about.

Moreover, I've already noted the problems with the theory that these strings are behaving as rods and so far these objections have not been addressed by anyone. I'll expound a little bit on a few of those points:

1) In each of the rod videos that were posted (which were fun to watch in and of themselves), the mounting of the rod was clearly at one point, a 2:1 nodal point, the middle. The rod's own rigidity allows this, and the l-waves thus produced are at their greatest amplitude at the rod ends. Problem is, the Earth Harp does not use rods (with their own rigidity, allowing for free-end vibration), rather, it uses "strings" (heavy gauge wires) which must be mounted at each end. This doesn't allow for any sort well-mannered periodic l-wave; It's a transverse wave environment.

2) In the rod videos, the swiping is done swiftly over nearly half the length of the rod and always from the nodal end outward, whereas with the Earth Harp, the swipe is very slow and even and the ratio of swipe to the length of the strings is very small, plus which you can never go from the 2:1 nodal mount point outward to a free end since there is no free end.

3) The decay time in one of the rod videos is about 12 seconds, and would've been even longer without the styrofoam cup being placed on the end a few times. Whereas, with the Earth Harp, the decay time is about one second. Instruments with decay times longer than about 1 second (timpani, chimes, cymbals, tam-tam, etc.) need to be dampened at certain points by the performer if the onset of a subsequent note would lack clarity (for being covered by a still-resonating instrument). But you'll notice that this does not happen with the Earth Harp, what with it's manageable decay time. At no point does the performer ever have to dampen. Chimes have similar decay times to the rods in the videos. You can't even really play moderately paced figures on the chimes without the notes getting lost in the wash, and with the timpani or glockenspiel (both having similar decay times of a few seconds), un-dampened quick-ish notes increasingly lose their clarity. Not so with the Earth Harp, with its decay time less than 10% that of the rods.

4) Speed of onset is another issue. The rod videos show a gentler full onset, whereas the Earth Harp has a quicker and more immediate onset. A 1000 foot long wire having a much quicker onset envelope than a 5 foot rigid bar cannot be reconciled to the principles of real world instrument acoustics.5) In each of the rod videos, the harmonic content is very simple and not very rich and does not in any way translate to the much thicker, more active, and decidedly nasal and buzzy harmonic content produced by the Earth Harp.

______________________________

And while an attempt was made to address a few of the red flags I listed in my original post, I already highlighted those errors as well. The physics of vibrating bodies are a very particular thing, and the particulars matter a great deal. Like I say, I've done a fair amount of formal study regarding general acoustics and especially instrument acoustics. As an experienced composer, I'm regularly evaluating sound by ear and with my spectrum analyzers, and I edit and process generated and sampled sound waves at the sample level. I perform all sorts of experiments on established instruments as well as "found percussion" (steel mixing bowls, steel dog food bowls, clay flower pots, different types of tone wood, conduit tubes, ceramic floor tile, etc.), plus which, I regularly scour the scholarly books on instrument acoustics which I own, so I can guarantee that none of what I say here is based on "assumptions".

Nevertheless, I am intellectually curious, so like I previously mentioned, I've sent out a few inquiries to some credentialed experts whose areas of specialty make this subject right up their alley. I'll report back here as soon as I get any replies.

Regardless, I'm not too fond of the New Age marketing speak whereby a valley "becomes the instrument".

Thanks for taking the time and interest.

-J
 
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  • #28


To hoax the thing, then, he'd have recordings of each note that were activated by pulling on the strings. The mikes he seems to be using as pickups would actually not be in operation. They would function as a front to explain the need for a loudspeaker system.

Is something like this what you're thinking?
 
  • #29


Jiminy said:
I haven't really made any assumptions about anything. I'm applying real-world acoustical principles, and I know for a fact that in the physical world, mass, resistance, amplitude envelope and frequency are inextricably linked, no matter what sort of wave you're talking about.

Moreover, I've already noted the problems with the theory that these strings are behaving as rods and so far these objections have not been addressed by anyone. I'll expound a little bit on a few of those points:

Your first post was an attempt to debunk the idea that this instrument utilizes transverse vibration of the strings to make it's sound. Almost all of your red flags from that post are completely invalid because the claim is that the instrument utilizes longitudinal vibrations of the strings.

Jiminy said:
And also notice that the rod is swiped nearly half of its entire length, whereas on the Earth harp, he swipes less than 10% of the length of the string. And In the canyon installation he'd be swiping less than 1%.

Notice in the video of the rod, that in the second swipe, the sound picks up, and is loud immediately as he starts swiping. The guy in the video does swipe all the way down the length, but it's not in any way necessary to do so to get the longitudinal effect he gets.

Jiminy said:
Moreover, in the two rod videos, the hand has to leave the rod immediately after the swift swipe to allow the rod to vibrate, whereas with the Earth harp, the hands remain on the strings.

Notice also that he's making sound from the moment he starts (while his hands are still swiping)
 
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  • #30


Zoobyshoe,

To be honest, I don't even want to contemplate it being a hoax. I would much prefer it were real. Maybe one of these acousticians will get back to me with something, some phenomenon I haven't taken into account, but so far I can't reconcile it. Plus which, it'll be much more interesting if it is real. Until I have it confirmed one way or the other I'm suspending my partial disbelief for the time being, because if I err, I want to err in favor of giving the guy the benefit of the doubt for now.

Theoretically speaking, if one were to fake this, the notes themselves would probably be generated via a physical modeling module rather than a sampling module. If it were samples, each one would have to be looped and you'd have to program seamless release triggers. All that would be much easier with physical modeling. Depending on how much off-the-shelf stuff vs. custom kit were used, you could potentially end up with something about the size of an iPhone, not including the triggering rig.

As far as triggering the notes is concerned, you'd need some sort of custom rig that responds either to the pressure applied to the string, or perhaps merely to touch, via the interruption of some sort of very low level electrical charge. He's got those things mounted on the each string roughly about 10 feet from his playing position, so those could be a terminal of sorts I suppose, but mechanical and electrical engineering are not areas I know anything about, so I could be talking out of my you-know-what as far as all that is concerned.

The most charitable scenario I've been able to come up with so far is that there is some part of this which is acoustically valid, and the aspect of the extra long strings, be they 50 feet or 1000, are just a part of the stagecraft, so to speak. And like I say, part of my problem is understanding why such a monumental disparity of string length per installation would result with notes of identical tuning.

I'll report back here when I find out something more concrete. I hope it's good news.

Enjoy your weekend everybody.
 
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  • #31


jreelawg said:
Your first post was an attempt to debunk the idea that this instrument utilizes transverse vibration of the strings to make it's sound.

Was it? How so? At what point in my first post did I posit that each and every of the 10 acoustical red flags I listed was based on transverse wave assumptions? And they certainly don't imply that themselves. Number 5 mentioned perpendicular/transverse excitation, so that makes 1 out of 10 being invalidated only if this turns out to be legitimate. For now, all you're basically saying is that "You're wrong because you're wrong", without really getting into the nitty gritty of the specifics. I am perfectly fine with being wrong about an interesting subject like this, I just want to know why.

My initial post was to list a number of acoustically-based red flags. Longitudinal vibration of a mass is not conjured from the teardrops of magical harp fairies, and that being the case, they are still subject to certain acoustical principles which somehow do not accommodate mere assertion or wishful thinking.

And as for saying that this is a longitudinal mechanism simply because someone has asserted same, well, again, that remains to be seen. If that is the case, it may very well be the first time in the history of music that someone has rubbed a wire parallel to its length and produced a musical, periodic wave form, high in active harmonic content, with an attack envelope and decay time that are both conveniently just right for common musical purposes.

jreelawg said:
Notice in the video of the rod, that in the second swipe, the sound picks up, and is loud immediately as he starts swiping. The guy in the video does swipe all the way down the length, but it's not in any way necessary to do so to get the longitudinal effect he gets. Notice also that he's making sound from the moment he starts (while his hands are still swiping)

Fact: It takes the guy with the 6 foot rod about half a second to make an initial full onset.

Fact: In musical terms, that's a long time.

Fact: The Earth Harp, with it's considerable length and increased mass (which, again I say, unlike the rod does not have a free end to vibrate since it must necessarily be mounted at both ends), has a very quick onset that is perfectly able to play the fast section at 1:37. Those are eighth notes at a tempo of about 108 bpm, meaning the notes themselves are about .27 or .28 of a second at the slowest. The singing rod has way too slow a response for this, and like I noted previously, the decay times are not even in adjacent ballparks.
 
  • #32


Jiminy, here's another rod video showing an effect I find paradoxical:



At about 1:45 he is holding the rod at the midpoint and getting a certain pitch.

Then he changes the point at which he's holding the rod, strokes the longer side, but gets a higher pitch.

The pitch the rod produces, it seems, is determined by the shortest of the two lengths, and that monopoly holds independent of which length you rub.

Maybe this is not mysterious to you, but it strikes me as counter to the more length = deeper pitch you'd (I'd) expect.
 
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  • #33


Jiminy said:
Fact: It takes the guy with the 6 foot rod about half a second to make an initial full onset.

Fact: In musical terms, that's a long time.

Fact: The Earth Harp, with it's considerable length and increased mass (which, again I say, unlike the rod does not have a free end to vibrate since it must necessarily be mounted at both ends), has a very quick onset that is perfectly able to play the fast section at 1:37. Those are eighth notes at a tempo of about 108 bpm, meaning the notes themselves are about .27 or .28 of a second at the slowest. The singing rod has way too slow a response for this, and like I noted previously, the decay times are not even in adjacent ballparks.

The singing rod only demonstrates the possible feasibility of something like what he created. It's really a very different thing though. It's hard to compare the two.

The strings being mounted on both ends must dampen the strings so that they don't ring out like the singing rod. Instead of the transverse wave reacting directly with the air, they must instead transfer energy to the vibrating body.

The singing rod is vibrated from the moment that the friction begins, it's just that it takes a certain amount of force applied to it to get it to vibrate a lot. While the sound initially is quiet, if he were to somehow apply more friction faster, it would be louder quicker.

Because the Earth harp may be dampened the way I suggested, it may not be able to ring out and build up with every additional stroke. And the instrument is amplified.

It would be interesting to know how loud the Earth harp is un-amplified.

Just a few thoughts.
 
  • #34


I'm searching for a video where someone tries clamping the rod at one or both ends. Haven't come up with any.


This video, though, shows what happened when the demonstrator experimented with bending a rod simply to make it easier to cart around from one demonstration to the next.

https://www.youtube.com/watch?v=MJ4GWk5uwMg

My guess is that the result has something to do with the fact he has "work hardened" the aluminum at the bend. This might be equivalent to clamping the rod in a vise, say, at one end, though I'm just speculating.
 
  • #35


jreelawg said:
It would be interesting to know how loud the Earth harp is un-amplified.
I'm thinking just about inaudible to the unaided ear. In all these videos the effect of repeated stroking is to increase the amplitude. The rods are certainly ringing softly at the first stroke and I think the secret of the "earth harp" is in the electronic amplification.
 
<h2>1. Is the Earth Harp a real instrument?</h2><p>Yes, the Earth Harp is a real instrument that was invented by musician and artist William Close in 1999. It has been featured in various performances and installations around the world.</p><h2>2. How does the Earth Harp produce sound?</h2><p>The Earth Harp works by using long strings attached to structures such as buildings or trees, and then attaching those strings to a resonating chamber. The vibrations from the strings are amplified through the chamber, creating a unique and ethereal sound.</p><h2>3. Can the Earth Harp be played like a traditional harp?</h2><p>While the Earth Harp does have strings like a traditional harp, it is played in a different way. Instead of plucking the strings with fingers, the Earth Harp is played by using hand-held bows to create vibrations and sound.</p><h2>4. What makes the Earth Harp different from other string instruments?</h2><p>The Earth Harp is unique in that it utilizes extremely long strings, some up to 1,000 feet in length, and attaches them to large structures. This allows for a much larger range of sound and creates a more immersive experience for listeners.</p><h2>5. Can the Earth Harp be played in different environments?</h2><p>Yes, the Earth Harp has been played in a variety of environments, from concert halls to outdoor spaces. However, the structure and placement of the instrument may need to be adjusted to accommodate different settings and produce the best sound possible.</p>

1. Is the Earth Harp a real instrument?

Yes, the Earth Harp is a real instrument that was invented by musician and artist William Close in 1999. It has been featured in various performances and installations around the world.

2. How does the Earth Harp produce sound?

The Earth Harp works by using long strings attached to structures such as buildings or trees, and then attaching those strings to a resonating chamber. The vibrations from the strings are amplified through the chamber, creating a unique and ethereal sound.

3. Can the Earth Harp be played like a traditional harp?

While the Earth Harp does have strings like a traditional harp, it is played in a different way. Instead of plucking the strings with fingers, the Earth Harp is played by using hand-held bows to create vibrations and sound.

4. What makes the Earth Harp different from other string instruments?

The Earth Harp is unique in that it utilizes extremely long strings, some up to 1,000 feet in length, and attaches them to large structures. This allows for a much larger range of sound and creates a more immersive experience for listeners.

5. Can the Earth Harp be played in different environments?

Yes, the Earth Harp has been played in a variety of environments, from concert halls to outdoor spaces. However, the structure and placement of the instrument may need to be adjusted to accommodate different settings and produce the best sound possible.

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