Is the Earth Harp real (acoustically)?

[Jiminy]

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.

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.

 

[zoobyshoe]

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.

 

[jreelawg]

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.

 

[zoobyshoe]

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.

 

[zoobyshoe]

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.

 

[Whiskey]

I suspect the vibration or tension from Close rubbing the string triggers a note on a synthesizer. I can't believe those long loose strings are actually making any sound.

And there are no patents related to the Earth Harp, just copyrights. It appears to be just showmanship.

 

[pdubbs]

My BS monitor also went off when I saw the "earth harp" no way that is real acoustic sound coming from the strings. Instead, I offer that is is merely a midi controller that is triggering a synthesizer/sampler somewhere. I write and produce electronic music and have made some interesting midi controllers using various household items. Just notice the lack of any microphones to mic the instrument and then notice how it perfectly fits in with his other played instruments and backing track. It is perfectly mixed and sits "well" in the track; too well for that matter. And it is too responsive to be what he actually says it is. Try to make sound from a wine glass quick like he does with the Earth harp

 

[tonytee1947]

All this discussion is so theoretical that I wonder why nobody has asked the obvious (at least to me) question. I'm not a physicist or even a scientist but I have professionally played a stringed instrument. Forget all the stuff about whether it's rods or cables; it's obviously cables of some kind. And the way this guy "plays" his "harp" is by running his hands, gloved or not, with rosin or not, along these cables. So the question is this; can this teeny (compared to a series of cables stretched over 100 feet) little man have a physical sound producing effect on these cables? This looks to me, just at first glance, to be something more in the realm of David Copperfield than the area of physics or music.

 

[tb2496]

in his latest performance on AGT I noticed that sometimes the sound he's suppose to play is played before he actually moves his hands to play it.

so for example the melody changes from one note to another but he has not moved his hands to another string yet. when he moves his hand to another string and touches/rubs it (maybe one second delay), no new note is triggered in what we hear.

which means the music is either prerecorded or someone else is playing what's suppose to be his sound/melody.

 

[Devils]

The Earth operates like a giant bell, it has a mainly liquid core & hard outer surface. Earthquakes make the bell ring.
http://en.wikipedia.org/wiki/Seismic_wave

Playing the Earth like a musical instrument is a bit far fetched though.

 

[dkotschessaa]

in his latest performance on AGT I noticed that sometimes the sound he's suppose to play is played before he actually moves his hands to play it.

so for example the melody changes from one note to another but he has not moved his hands to another string yet. when he moves his hand to another string and touches/rubs it (maybe one second delay), no new note is triggered in what we hear.

which means the music is either prerecorded or someone else is playing what's suppose to be his sound/melody.

I just watched a bunch of these videos and the stage lighting really makes it difficult to discern anything like this. In the true spirit of skepticism I think it is best to refrain from depending too much on "sense input" of this type.