Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Secret of the Banjo's Unique Sound Discovered By Nobel Prize-Winning Physicist

timothy posted about 4 months ago | from the ok-now-tell-us-why-people-like-it dept.

Music 101

KentuckyFC (1144503) writes The banjo is a stringed instrument that produces a distinctive metallic sound often associated with country, folk and bluegrass music. It is essentially a drum with a long neck. Strings are fixed at the end of the neck, stretched across the drum and fixed on the other side. They are supported by a bridge that sits on the drum membrane. While the instrument is straightforward in design and the metallic timbre easy to reproduce, acoustics experts have long puzzled over exactly how the instrument produces its characteristic tones. Now David Politzer, who won the Nobel prize for physics in 2004, has worked out the answer. He says the noise is the result of two different kinds of vibrations. First there is the vibration of the string, producing a certain note. However, the drum also vibrates and this pushes the bridge back and forth causing the string to stretch and relax. This modulates the frequency of the note. When frequency of this modulation is below about 20 hertz, it creates a warbling effect. Guitar players can do the same thing by pushing a string back and forth after it is plucked. But when the modulating frequency is higher, the ear experiences it as a kind of metallic crash. And it is this that gives the banjo its characteristic twang. If you're in any doubt, try replacing the drum membrane with a piece of wood and the twang goes away. That's because the wood is stiffer and so does not vibrate to the same extent. Interesting what Nobel prize-winning physicists do in their spare time.

Sorry! There are no comments related to the filter you selected.

banjo is for poor people (-1, Troll)

Anonymous Coward | about 4 months ago | (#47341973)

Let's have some more stories relevant to GOP social climbers who are sure to be rich real soon. You don't become a 1%er by playing the banjo, no siree.

Re:banjo is for poor people (1, Interesting)

ArcadeMan (2766669) | about 4 months ago | (#47342005)

Banjo is for robots [theinfosphere.org] .

Re: banjo is for poor people (0)

Anonymous Coward | about 4 months ago | (#47347477)

I'm a banjoist and can ascertain that banjos are not cheap. Historically, they were, but as with most things, they are now made with superior woods and such. My last expensive banjo was 850$ and 20 years old.

Re:banjo is for poor people (-1)

Anonymous Coward | about 4 months ago | (#47342193)

Trolling is for intelligent people. Not morons like you.

Re:banjo is for poor people (0)

Anonymous Coward | about 4 months ago | (#47342845)

Your investment portfolio isn't paying out like you'd hoped, guy?

Re:banjo is for poor people (2)

Ol Biscuitbarrel (1859702) | about 4 months ago | (#47343273)

Actually the highest priced banjo on eBay is currently going for $24,900. [ebay.com] Some vintage 5 strings sell for ca. $75k or more; by my informal estimate your average bluegrass musician spends about $1.5k on their instrument, some more than that. Contrast that with how you can buy a serviceable electric guitar at box stores for $200. I don't know what the typical rocker is spending these days, and indeed some spend tens of thousands on old Fenders and Gibsons, but I'd reckon that bluegrass banjo players are anything but poor.

Re:banjo is for poor people (0)

Anonymous Coward | about 4 months ago | (#47343351)

well some violin sell for millions

Re:banjo is for poor people (1)

flyneye (84093) | about 4 months ago | (#47344429)

Contrast that with high end new archtop guitars selling between $30-60k and vintage ones where the sky is the limit.
Truthfully, you can get most instruments in a variety of price ranges, dependent on your needs or vanity.
The short lifecycle of a $200 instrument usually ends up in a spare parts drawer. Most instruments over $10k don''t see much more action than the studio or a display case. A good all round workhorse guitar for most uses SHOULD weigh in around $3-5k, the higher end of "off the rack".
A good banjo should bring enough at pawn to bail its owner out of jail as a general rule.

Re:banjo is for poor people (0)

Anonymous Coward | about 4 months ago | (#47345007)

I wouldn't call any guitar in the $200 price range "serviceable" for any player past the beginner stage. Most of my own guitars, both acoustic and electric, retail for $1800 and up, although I have a couple of good ones at around the $800 mark.

Now you have found me... (1)

Anonymous Coward | about 4 months ago | (#47341995)

what a Happy instrument (4, Funny)

turkeydance (1266624) | about 4 months ago | (#47342007)

You just can't sing a depressing song when you're playing the banjo. You can't go-- "Oh, murder and death and grief and sorrow!" --Steve Martin http://snltranscripts.jt.org/7... [jt.org]

Re:what a Happy instrument (2)

rev0lt (1950662) | about 4 months ago | (#47342031)

My favourite banjo song: https://www.youtube.com/watch?... [youtube.com]

Re:what a Happy instrument (-1)

Anonymous Coward | about 4 months ago | (#47342107)

Next research project worthy of a Nobel prize: Why do they sing like that?

Re: what a Happy instrument (2)

bill_mcgonigle (4333) | about 4 months ago | (#47342239)

not as socially poignant as Space Worms [youtube.com] .

Re:what a Happy instrument (2)

i.r.id10t (595143) | about 4 months ago | (#47342783)

Think most folks here and geeks in general would recognize this one -

The Eagles-Journey of the Sorcerer [youtube.com]

Re:what a Happy instrument (0)

Anonymous Coward | about 4 months ago | (#47351259)

Wow! Cool, as is the accompanying Youtube video!

Re:what a Happy instrument (0)

Anonymous Coward | about 4 months ago | (#47342169)

I think every song on a banjo is depressing.

Of course you can (1)

billstewart (78916) | about 4 months ago | (#47342363)

That's what all the weird minor keys and modes are for.

Re:what a Happy instrument (0)

Anonymous Coward | about 4 months ago | (#47342731)

Clifton Hicks [youtube.com] seems to have managed.

Re:what a Happy instrument (1)

Cow Jones (615566) | about 4 months ago | (#47344145)

This one sounds sad enough: http://youtu.be/14BmN_ejBX4 [youtu.be]
Beautiful, too.

Re:what a Happy instrument (0)

Anonymous Coward | about 4 months ago | (#47354239)

Death Metal Banjo?

The real secret (3, Informative)

hedgemage (934558) | about 4 months ago | (#47342013)

The drum membrane is made out of 'possum skin.

Re:The real secret (2)

LifesABeach (234436) | about 4 months ago | (#47342077)

This sure looks like a candidate for an IgNobel?

Banjo = guitar + snare drum (-1)

Anonymous Coward | about 4 months ago | (#47342015)

I don't see how this is a revelation at all. A banjo is essentially a guitar with a snare drum for a body. The reverberation of the drum head affects the vibration of the strings. I am but a lowly musician (and a mediocre one, at that) and knew this "secret" already.

Experiment: build an acoustic guitar but instead of having a hollow body, use a solid piece of wood. Notice how it becomes a lot quieter? AMAZING DISCOVERY.

Re:Banjo = guitar + snare drum (5, Informative)

Kkloe (2751395) | about 4 months ago | (#47342185)

yes but have you written it down? have you done the math behind it?
here is the original paper http://arxiv.org/pdf/1406.4907... [arxiv.org]

Re: Banjo = guitar + snare drum (3, Interesting)

O('_')O_Bush (1162487) | about 4 months ago | (#47343211)

Does it need to be written down? It wasn't like the banjo was accidentally made... it was designed that way. That is why there are all sorts of hybrid instruments, like the Dulcijo (dulcimer banjo), where the whole body is designed to be just like a normal dulcimer except for the bridge, which sits atop a tiny drum head like a banjo does.

Bridge+vibrating support for the bridge + vibrating strings = banjo sound has been no big secret for a long time.

It is neat he did math behind it, but the summary makes claims about how mysterious it was, and that sounds pretty ridiculous.

Re: Banjo = guitar + snare drum (0)

Anonymous Coward | about 4 months ago | (#47343381)

It is neat he did math behind it, but the summary makes claims about how mysterious it was, and that sounds pretty ridiculous.

And that is the nature of science reporting these days. The original paper doesn't call it a mystery, and at most says it is a "reasonable question" to ask what quantitatively distinguishes the sound of the banjo family of instruments from other stringed instruments. If the PR machine picks up on a paper though, even the smallest of incremental improvements that has heavy citations in the original paper (even right in the abstract...) to previous work, the scientist's work suddenly becomes solving the greatest unsolved mystery in their field. While it is one thing to drum up interest in science, frequent trends like that give a false impression of what science work is really like, where a large number of scientists are busy slogging out the details and improving on previous work incrementally most of the time.

Re:Banjo = guitar + snare drum (1)

Anonymous Coward | about 4 months ago | (#47343579)

No offense, but this was a complete waste of an article. You ask anyone associated with making this or any stringed instrument and they could have easily given you the answer. There's reasons why instrument makers use or experiment with different bridge, body, fret board, the frets themselves with different materials. Most stick to standard materials. I've seen Banjo's in slow motion and can easily see how the details, such as the vibrations from the entire instrument.

Just because the guy is a Nobel peace prize winner, this doesn't make him the only person on the planet to have figured this out. And I'm sure because this is a geek and nerd site everyone will pretend as if this story and the man behind the -already known- reasons for a Banjo's tone, he will be immediately worshiped.

Re:Banjo = guitar + snare drum (0)

Anonymous Coward | about 4 months ago | (#47344933)

The vast majority of people involved with such instruments, including those that make them, are not going to give you quantitative answers or any answer involving math to questions about the instruments (the most consistent exception being engineers and hobbyists working on making synthesizers). A lot of design work in musical instruments is a mix of tradition and phenomenology, which in the end works quite well as people can be quite skilled at making them without sitting down to treat the problem like an engineer would with modeling, etc (not to say that some don't take a more quantitative approach). .

I used to work in a physics department at a university with a strong music program, and spent time volunteering for physics outreach. It didn't take long before you could pick out the people who were from the music program (more often the professors and their variety of friends from the industry than the students) because they would stop and ask a variety of in depth questions about some of the wave based demonstrations, while others would just stare and not say anything more than "oh cool." These people knew basic principles of things, but were interested in the details, especially how to predict and understand things without just trying things out. A favorite was the generations of patterns in sand using different vibrating shapes, which while familiar to many of them, they still would spend a long time talking and asking questions about how the structures form and the relationship between different modes, etc. They know about harmonics and at least the image of 1D and 2D modes, but don't know about solving for eigenmodes and how to get the relative strength between them, coupling, etc., beyond knowing that certain things just work.

In this case here, it looks like some professor just has a hobby and decided to write up a bit about it. He seems to have an interest in string instruments, and on his website has images from a collection and talks about doing restoration work on them. The paper he wrote doesn't make any grandiose claims, just a typical introduction and some brief work he did figuring out the why the sound is distinct and reproducing it through software. I don't even see if this was actually published anywhere other than just uploaded on arxiv. Plenty of physicists have hobbies, and get around to applying their physics background. Sometimes this spills over into examples used in classes or in special topic courses for people with similar interest (a lot of universities have someone teaching an electric physics of music course) other times it just ends up on a blog or a collection of write-ups. Medium here seems to be the one that applied the usual problems of the science news cycle (and wouldn't be the first time...), turning some physicist doing something for fun on the side into a bunch of hyperbole.

dont need to replace the drumhead.... (4, Interesting)

Lumpy (12016) | about 4 months ago | (#47342019)

Just hold a thumb against it. a Lot of us players do that to adjust the sound for different "expression"

Re:dont need to replace the drumhead.... (1, Informative)

Charliemopps (1157495) | about 4 months ago | (#47342165)

Just hold a thumb against it. a Lot of us players do that to adjust the sound for different "expression"

Right... this seems like more of "A scientist that doesn't know anything about music explains something everyone who plays already knew" type of thing.

Re:dont need to replace the drumhead.... (5, Insightful)

sribe (304414) | about 4 months ago | (#47342281)

Right... this seems like more of "A scientist that doesn't know anything about music explains something everyone who plays already knew" type of thing.

No, more like: everybody pretty much knew that the bridge being mounted on a vibrating membrane would affect the sound, but a scientist thoroughly analyzed and modeled the whole setup in order to quantitatively figure out exactly how all the parts and vibrations contributed to the sound. Then a dumbass know-nothing journalist wrote an article that misstated what had actually happened ;-)

Re:dont need to replace the drumhead.... (1)

umghhh (965931) | about 4 months ago | (#47343831)

you forgot the endless bitching on /. about dumbass half brain of a scientist while at the same time not being able to explain the exact mechanics of the banjo effect.

I am half burnt now but I still remember times at school when this sort of explanations provided me with joy at learning stuff like physics and math instead of listening to explanation of a teacher that has no f. clue what he is talking about and what role his 'knowledge' has in my and my fellow students reality, combined with explanations in another subject ended with 'it is just so'. I am not sure we have to shoot things into orbit just to find out that parking lot without trees is hotter than one with them but I like when there are formulas at hand when one asks for them.

Neat (0)

Anonymous Coward | about 4 months ago | (#47342021)

So I guess this will get him an Ig Nobel prize for finding out why a banjo sounds like a banjo?

What about the Nobel prize-winning biologists? (3, Funny)

ArcadeMan (2766669) | about 4 months ago | (#47342025)

I've heard some of them are still searching for that elusive Gräfenberg spot in their spare time.

Ig Noble (1)

excelsior_gr (969383) | about 4 months ago | (#47342055)

I think he's just going for the Ig Noble prize.

Re: Ig Noble (1)

bill_mcgonigle (4333) | about 4 months ago | (#47342251)

then go out with a Darwin for the hattrick?

Re:Ig Noble (1)

itzly (3699663) | about 4 months ago | (#47343341)

Nah, he's going for the Politzer prize.

Yeah (0)

Anonymous Coward | about 4 months ago | (#47342061)

If you're in any doubt, try replacing the drum membrane with a piece of wood and the twang goes away.

The evidence is that if you change a fundamental part of the instrument, it no longer has its distinctive sound? I think we could have guessed that much.

Lousy Self-Centered Biologist (0)

Anonymous Coward | about 4 months ago | (#47342069)

Bastard ruined all the fun of a great musical instrument that has stood the test of time and silenced its harmonious metallic twang just to reinforce his own intelligence to the public ear.

I hope someday some bored hillbilly discovers a way to use fried chicken to prove that David Politzer was nothing more than a hack who ripped off the ideas of some crazy back-hills mountain man who was the real brains behind quantum chromodynamics.

OK (0)

Anonymous Coward | about 4 months ago | (#47342095)

now explain the sitar...

Sitars (4, Informative)

billstewart (78916) | about 4 months ago | (#47342353)

The sitar has several things going on with it

  • -- The body has a chamber made from a big gourd, and a wooden neck with adjustable frets.
  • -- There's a layer of strings that you pick, optionally pressing on the string over a fret to change the pitch.
  • -- There's another layer of strings underneath that resonate when you play the note they're tuned to on the main strings, which provides some amplification and a lot of sustain; that's one of the things that gives the sitar its characteristic sound.
  • -- In addition to fretting a string when you pick it, you can also bend it to the side, changing the pitch dynamically, which is another characteristic sitar sound. Guitar and bass players also use this technique, but sitar strings are long enough that it's easier to do.
  • -- Generally there are two or three strings that you'll play the melody notes on, and several more strings that you pick without fretting, letting them drone like a mountain dulcimer; that's another characteristic sitar sound.
  • That's most of the technology parts; the rest is about the music itself.

Indian classical music theory is complex, at least as much as European classical music theory or jazz. There's a lot of stuff about "ragas", which are a combination of a scale or scales, melodies, fixed parts and improvised parts, with a lot of rules about which ones are appropriate for which situations.

Re:OK (1)

NemoinSpace (1118137) | about 4 months ago | (#47344439)

Acid. That explains Harrisons early use anyway. There were others, but without copious amounts of acid on both the player and the listener, it fell out of favor. Now, the scientist that invented acid, Hoffman - that's the guy you want to read about.

he must be bored (0)

epyT-R (613989) | about 4 months ago | (#47342105)

Doesn't he have anything better to do?

Re:he must be bored (1)

bswarm (2540294) | about 4 months ago | (#47342201)

I was thinking the same, it really doesn't take a rocket scientist to figure out a banjo has dual harmonic vibrations. Duh, it has a drum and some strings. Maybe he should patent-troll it so he can try and collect for every banjo ever made.

Re: he must be bored (1)

O('_')O_Bush (1162487) | about 4 months ago | (#47343221)

As I pointed out elsewhere, it is common knowledge to traditional music makers that a vibrating bridge makes the banjo sound. That is why there are instruments like this:

http://www.gardnersdulcimer.com/data/Images_Additional/dulcijo3.jpg

Designed just like this:

http://gibsondulcimers.com/In%20Stock/Baritone%20Dulcimer%2047609/Baritone%20Dulcimer%2047609%20Front.jpg

Except, big surprise, they put a tiny drum head only under the bridge so that the bridge could vibrate and make a more banjo-ey sound.

Re:he must be bored (1)

Anonymous Coward | about 4 months ago | (#47342257)

Yeah, that asshole better apologize wasting your precious /. time with his irrelevant, unapproved research. How dare he!!!

Re:he must be bored (1)

epyT-R (613989) | about 4 months ago | (#47343085)

I just don't see how this is really news of interest. I mean, good for him if he wanted to figure it out, but the discovery does not warrant coverage just because he's a nobel prize winner.

Re:he must be bored (0)

Anonymous Coward | about 4 months ago | (#47343713)

No, you are supposed to worship any accredited person and the rest don't matter as they obviously have nothing to contribute.

Re:he must be bored (-1)

Anonymous Coward | about 4 months ago | (#47342411)

Maybe he is studying Republicans. It's important to know the enemy if you want to defeat them. Just why are they so racist, lazy, and fat? If we answer those questions we may can change pre-K education to keep kids off of the path of becoming one of them.

Re:he must be bored (0)

Anonymous Coward | about 4 months ago | (#47342543)

No good, repubs "home school" with belts and rods to beat "family values" into their kids.

Re: he must be bored (0)

Anonymous Coward | about 4 months ago | (#47342729)

I don't see how labeling Republicans as lazy and fat is less wrong than calling women lazy and fat. And since doing so will never help you communicate with Republicans, I would assume that you don't intend to make life on this planet better through understanding and a communication. So what are you going to do, eradicate them at some point and then hope that whoever is left over will agree with you about everything?

Re:he must be bored (1)

Anonymous Coward | about 4 months ago | (#47343107)

Nah, he's studying liberalism. It's important to understand the enemy's ego-driven, self important, aggrandizing motivations, faux sophistication, and how they interact with the inherent fallacies of marxist ideology. Then we can change pre-K education to keep kids off the path of professional victim degeneration and concern-troll lawyering, and focus them towards independent thought and critical thinking, where fallacious sacred cows, like consensus and feelings, don't take precedent.

Re:he must be bored (0)

Anonymous Coward | about 4 months ago | (#47345289)

I always laugh when "Christian" politicians rail on about how people shouldn't make decisions based on "feelings," yet they follow a religious figure, Jesus, who preached love as the basis for all our choices in life. Guess what "love" is?

Limited Ears (0)

Anonymous Coward | about 4 months ago | (#47342125)

One point is that it is the disability of human hearing which enables hearing the metallic character of the banjo. Brass wind instruments are also subject to human, hearing limits as the player receives some of the sound through the jaw bone vibrations, and also hears sounds projected by the body of the instrument whereas the audience hears what is projected from the bell of the instrument. As the hearing of each player is different players tend to get overly concerned about brand and model of an instrument as their own ears deceive them a bit. Sometimes the player may feel that he did not play all that well and yet the audience is very impressed and the reverse can also be true.

fm (0)

Anonymous Coward | about 4 months ago | (#47342139)

noice! mechanical FM synthesis :D

Lewis... (0)

Anonymous Coward | about 4 months ago | (#47342159)

we got a live one here.

So the banjo is FM (1)

Anonymous Coward | about 4 months ago | (#47342205)

So the banjo is acoustic frequency modulating. When was the first electronic FM synth invented? It would be interesting if some engineers could take this one step further and create a mechanical FM synth. How high a frequency could you get, and what kind of sounds could you build?

Banjo jokes (5, Funny)

tomhath (637240) | about 4 months ago | (#47342209)

Q: How can you tell if the stage at a Bluegrass concert is level?

A: The banjo player drools out of both sides of his mouth.

Re:Banjo jokes (0)

Anonymous Coward | about 4 months ago | (#47342287)

Q: What do you call 50 banjos in a dumpster?

A: A good start.

Re: Banjo jokes (0)

Anonymous Coward | about 4 months ago | (#47347207)

I believe that is called perfect pitch

Re: Banjo jokes (1)

bregmata (1749266) | about 4 months ago | (#47354365)

No, perfect pitch is where you toss a banjo into a dumpster and it hits the accordion.

Re: Banjo jokes (0)

mtcups (1613413) | about 4 months ago | (#47347213)

I believe that is called perfect pitch

Re:Banjo/drummer/viola/accordion jokes (1)

billstewart (78916) | about 4 months ago | (#47342373)

Most of them can be recycled easily between genres; the drummer jokes (or bass player jokes) are more likely to be about the players, while the others are more likely to be about the instruments themselves, but either way.

I did see somebody the other day with a t-shirt captioned "First violinist problems", showing a musical staff and a note about 10 lines above the staff.

Banjos...not a fan... (5, Funny)

VAXcat (674775) | about 4 months ago | (#47342211)

One day my old pal David has played a gig with some local musicians, including his roommate, Bob, who was a banjo player. After the set, Bob was going somewhere else with some other people, so he asked Dave to take his banjo home for him. On the way home, David stopped at the convenience store to get a six pack. As he was standing in line, he suddenly realized that he had left the car windows down, and that he was in a bad neighborhood. He rushed out, but, sure as hell, the worst possible thing had happened - exactly what he was afraid of - someone had spotted the open car windows, and thrown two more banjoes in the car.

Re:Banjos...not a fan... (1)

Anonymous Coward | about 4 months ago | (#47342631)

http://pic20.picturetrail.com/VOL1600/965874/3155343/180717318.jpg

Re:Banjos...not a fan... (1)

TeknoHog (164938) | about 4 months ago | (#47343821)

On the plus side, you can use the disabled parking space if your banjo is clearly visible.

OP is obliquely critical of Politzer (3, Insightful)

aurizon (122550) | about 4 months ago | (#47342295)

! Interesting what Nobel prize-winning physicists do in their spare time. !

This tells the tail of an inquiring mind that turns it's focus on many things. He reminds me of Fenman, among many similar Nobel Laureates, whose curiosity was not limited by a 9-5 mentality, but was active 24/7.

It is this quality that produces the Nobels...

Re:OP is obliquely critical of Politzer (1)

aurizon (122550) | about 4 months ago | (#47342711)

typo, should be Feynman in my RP

Re:OP is obliquely critical of Politzer (1)

Ultracrepidarian (576183) | about 4 months ago | (#47343241)

It's OK. Most of these banjo fans spell Nobel Noble.

Re:OP is obliquely critical of Politzer (1)

Enigma2175 (179646) | about 4 months ago | (#47343283)

Really, you're going to fix Feynman but not going to fix "Tell the tail" or Politzer?

Re:OP is obliquely critical of Politzer (1)

aurizon (122550) | about 4 months ago | (#47343597)

Arrrgh, typos breed like flies with machines that that both present a tiny view and finish words for you...

old news (0)

Anonymous Coward | about 4 months ago | (#47342375)

Myself and many other banjo enthusiasts have known this for years. Why is this news?

Re:old news (0)

Anonymous Coward | about 4 months ago | (#47344423)

God, every time a new science article appears, a dozen idiots pop up claiming they "know it all along."

Not the first one. (4, Interesting)

140Mandak262Jamuna (970587) | about 4 months ago | (#47342795)

He is not the first Nobel Laureate to be fascinated by the drums and vibrating membranes. Sir C V Raman, of the Raman Effect fame, was intrigued by the Indian drums, the Tabla and the mridangam. He published why and how they produce harmonics (paywall) [nature.com] back in 1920s. A synopsis [wordpress.com] .

In some sense it is not a surprise because his main work was on vibrating electromagnetic fields, and the natural modes of vibration of circular membranes is a very good way to practice the mathematics of vibrations.

Re:Not the first one. (0)

Anonymous Coward | about 4 months ago | (#47343159)

He also invented Raman noodles. Busy fucking guy!

Interesting spare time (5, Interesting)

Anonymous Coward | about 4 months ago | (#47342883)

Richard Feynman enjoyed playing the bongo drums, picking locks, and whatnot; and also

Then I had another thought: Physics disgusts me a little bit now, but I used to enjoy doing physics. Why did I enjoy it? I used to play with it. I used to do whatever I felt like doing - it didn't have to do with whether it was important for the development of nuclear physics, but whether it was interesting and amusing for me to play with. When I was in high school, I'd see water running out of a faucet growing narrower, and wonder if I could figure out what determines that curve. I found it was rather easy to do. I didn't have to do it; it wasn't important for the future of science; somebody else had already done it. That didn't make any difference. I'd invent things and play with things for my own entertainment.
So I got this new attitude. Now that I am burned out and I'll never accomplish anything, I've got this nice position at the university teaching classes which I rather enjoy, and just like I read the Arabian Nights for pleasure, I'm going to play with physics, whenever I want to, without worrying about any importance whatsoever.

Within a week I was in the cafeteria and some guy, fooling around, throws a plate in the air. As the plate went up in the air I saw it wobble, and I noticed the red medallion of Cornell on the plate going around. It was pretty obvious to me that the medallion went around faster than the wobbling.

I had nothing to do, so I start to figure out the motion of the rotating plate. I discover that when the angle is very slight, the medallion rotates twice as fast as the wobble rate - two to one [Note: Feynman mis-remembers here---the factor of 2 is the other way]. It came out of a complicated equation! Then I thought, ``Is there some way I can see in a more fundamental way, by looking at the forces or the dynamics, why it's two to one?''

I don't remember how I did it, but I ultimately worked out what the motion of the mass particles is, and how all the accelerations balance to make it come out two to one.

I still remember going to Hans Bethe and saying, ``Hey, Hans! I noticed something interesting. Here the plate goes around so, and the reason it's two to one is ...'' and I showed him the accelerations.

He says, ``Feynman, that's pretty interesting, but what's the importance of it? Why are you doing it?''

``Hah!'' I say. ``There's no importance whatsoever. I'm just doing it for the fun of it.'' His reaction didn't discourage me; I had made up my mind I was going to enjoy physics and do whatever I liked.

I went on to work out equations of wobbles. Then I thought about how electron orbits start to move in relativity. Then there's the Dirac Equation in electrodynamics. And then quantum electrodynamics. And before I knew it (it was a very short time) I was ``playing'' - working, really - with the same old problem that I loved so much, that I had stopped working on when I went to Los Alamos: my thesis-type problems; all those old-fashioned, wonderful things.

It was effortless. It was easy to play with these things. It was like uncorking a bottle: Everything flowed out effortlessly. I almost tried to resist it! There was no importance to what I was doing, but ultimately there was. The diagrams and the whole business that I got the Nobel Prize for came from that piddling around with the wobbling plate.

-- Surely you're joking, Mr. Feynman (c) 1985, PP 157-158

Re:Interesting spare time (0)

Anonymous Coward | about 4 months ago | (#47345019)

That's nothing. When I was bored at lunch I tried to work out the math of the low frequency vibration mode of paired loosely coupled lightly damped hemispheres. Trouble was I never got to the math, my mind just got stuck at the mental image [break.com] of what I was trying to model

Re:Interesting spare time (1)

ToddInSF (765534) | about 4 months ago | (#47345337)

Thank you very much for sharing this !

This has been known about for a long time. (3, Interesting)

Anonymous Coward | about 4 months ago | (#47343001)

Florian Pfeiffle and Rolf Bader wrote a paper called "Real-Time Physical Modelling of a complete Banjo geometry using FPGA hardware technology" that explores this:

http://www.systmuwi.de/Pdf/Papers/Bader%20papers/Physical%20Modeling/PhysicalModeling_Banjo/Pfeifle,Bader_04FPGA_Format.pdf

Re:This has been known about for a long time. (0)

Anonymous Coward | about 4 months ago | (#47345477)

Yes but was he a nobel prize laureate?

FM (1)

Anonymous Coward | about 4 months ago | (#47343055)

This effect on timbre is well known and was the basis for the range of Yamaha DX synthesizers in the 1980s. Basically when a tone is modulated (pitch changed) at high speed, instead of hearing a vibrato, you hear it as additional overtones, i.e. a change in the quality (timbre) of the sound. This technique is called Frequency Modulation (FM). It's especially useful for generating metallic and bell-like tones, like the famous FM electric piano sound of the 1980s.

The vibration of the drumhead at audio frequencies causes additional overtones through an FM effect. Damping the drumhead (or replacing it with a solid alternative) eliminates this effect and the additional overtones created. This is basic synthesis theory that any keyboard player would know.

Unsurprisingly, FM synthesizers can do a very convincing banjo copy.

Re:FM (1)

Alioth (221270) | about 4 months ago | (#47348793)

The size and construction of the head probably makes quite a lot of difference. I have an old Dallas D banjo ukulele (a George Formby branded one, no less) and the head had an inner hoop in it which makes the effective area of the head a bit smaller than the entire diameter. As such the overtones are softer and it sounds less "banjoey" (but still very different from a standard ukulele). The other consequence of the banjo uke head is that if you play a chord like F# where one string is not strummed, you need to mute the string that's not played otherwise the head will cause the string to vibrate and make the chord sound awful.

The Tumbi goes.... (0)

Anonymous Coward | about 4 months ago | (#47343343)

bunka-bunka-dinky-dinky-KHALISTAN ZINDABAD!

Sound of a basketball (0)

Anonymous Coward | about 4 months ago | (#47343709)

Here is a similar recent article analyzing the sound made by a bouncing basketball:

http://arxiv.org/pdf/0808.3278... [arxiv.org]

Huh? (0)

Anonymous Coward | about 4 months ago | (#47343795)

WTF? I've played string instruments for many years, and I'm astonished that it took so much research to prove what those of us that pley the banjo always knew.

Whats the difference (0)

Anonymous Coward | about 4 months ago | (#47343851)

Between a banjo and an onion?
Nobody cries when you cut up a banjo. ;-)

Thanks for explaining what a banjo is. (0)

Anonymous Coward | about 4 months ago | (#47343867)

I would never have guessed.

"The banjo is a stringed instrument that produces a distinctive metallic sound often associated with country, folk and bluegrass music. It is essentially a drum with a long neck."

WTF? Who could NOT know this?

Re:Thanks for explaining what a banjo is. (0)

Anonymous Coward | about 4 months ago | (#47344377)

Oh, god. Shut the fuck up, Mr. Know-it-all.

Joke (0)

Anonymous Coward | about 4 months ago | (#47344341)

What is the difference between a banjo and a motorcycle?

You can tune a motorcycle.

Discovery vs Publicity (0)

Anonymous Coward | about 4 months ago | (#47344699)

Is it fair to say he discovered this secret? I respect his status as a nobel prize winner, but could he not have simply publicized this knowledge? It is far more likely that a banjo player or maker has long since discovered this fact about their instrument and has even related the concept to others. I know the voice of an honored somebody will always be louder than that of an honest nobody, but still the headline does seem to eschew impartiality in favor of spectacle.

Do you have room in your heart... (0)

Anonymous Coward | about 4 months ago | (#47344751)

For the 5-string banjo?

That plunking sound...

Do you have room in your heart for the 5-string banjo?

It's round...

Finally! (1)

zawarski (1381571) | about 4 months ago | (#47344973)

My bucket list is complete.

FTFY (1)

SpaceBuggy (3689757) | about 4 months ago | (#47345181)

"...acoustics experts with too much free time have long puzzled over exactly how the instrument produces its characteristic tones."

A lot like FM synthesizers, apparently (0)

Anonymous Coward | about 4 months ago | (#47345291)

Yamaha's iconic DX7 keyboard broke new sonic ground with its "FM synthesis" model, which allowed a note to be frequency-modulated at any desired rate and amount. This gave it the ability to make those "clangy" tones that are so characteristic of FM, and that are apparently produced naturally by the banjo.

What this means! (1)

frank_adrian314159 (469671) | about 4 months ago | (#47346745)

Overheard at banjo manufacturers worldwide:

Gentlemen, we now have the technology to make a banjo that doesn't sound sucky!

But then how would anyone know it's a banjo?

A major award (0)

Anonymous Coward | about 4 months ago | (#47346889)

Confirming he got a Nobel prize for something real and not figuring out how a man made musical instrument works.

finally, a scientific explanation (1)

DulcetTone (601692) | about 4 months ago | (#47347011)

How long before before we field a serviceable apology?

Load More Comments
Slashdot Login

Need an Account?

Forgot your password?