The Physics of Lead Guitar Playing

[Joe Gwinn]

I came across this in an electronics-related trade rag.

The Physics of Lead Guitar Playing

Citation: The paper 'String theory – the physics of string-bending and other electric guitar techniques' by David Robert Grimes is published in the journal PLOS ONE. The author is at the University of Oxford in the UK.

[bbsailor]

Most Western music and guitar fret spacings are based on the 12th root of 2 with the frequency of the open string exactly two times higher at the 12th fret. http://en.wikipedia.org/wiki/Twelfth_root_of_two Voices can hit any notes between fixed scale intervals to stylize a song, create tension and resolution. Just listen to any of Gladys Knight songs or any sax player who trys to articulate the sax notes like a human vocalization for a stylized signature sound.

Playing the guitar can mimick vocal chords because the notes are not just fixed by the frets but can be stretched by finger action or loosened by a vibrato to connect notes in a more interesting and stylized way. With electric guitars the range of sounds increases with added gain, sustain and distortion along with interesing string bends. Just listen to the guitar lead on Hotel California for a good example of this.

Joseph Rogowski

[ric]

Just listen to the guitar lead on Hotel California for a good example of this.

Joseph Rogowski

Kind of chichen pickin with sustain.

[ric]

Kind of chichen pickin with sustain.

Ok, maybe not. That's what I hear but don't let it be a thread killer.

This topic should be interesting. Lead guitar/amps...come on.

David, thanks for putting Joseph's quote back in a blue box in previous post. First time trying to edit a quote to just the part I was trying to speak to.

[Mike Sulzer]

"But no one has previously worked out how effects like bending the string change the pitch of the sound." Does anyone have a link to the PLOS ONE article? There has to be a lot more to it than that quote from the "review" that Joe referred to. If you have the physical characteristics of the string, and some idea of how little the neck bends in response to string bending, it is not so hard to work out the effects of string bending.

I came across this in an electronics-related trade rag.

The Physics of Lead Guitar Playing

Citation: The paper 'String theory – the physics of string-bending and other electric guitar techniques' by David Robert Grimes is published in the journal PLOS ONE. The author is at the University of Oxford in the UK.

[g1]

Here's the actual article: PLOS ONE: String Theory - The Physics of String-Bending and Other Electric Guitar Techniques

[J M Fahey]

Well, the original paper is:
PLOS ONE: String Theory - The Physics of String-Bending and Other Electric Guitar Techniques

EDIT: huh!!!!! simulposting!!!!

[tedmich]

http://www.plosone.org/article/fetch...esentation=PDF

PLOS one is a decent journal, a bit more than its share of retractions but hey...

[tedmich]

Now THAT'S a string theory! Physicist reveals how science could make you a better guitar player | Mail Online
video is therin, guy plays waaaay wet on an Ibanez, decent but no Uli

[J M Fahey]

Excellent no nonsense investigation and well written article.

And compact to boot, others might have written 200 pages to say the same

[Mike Sulzer]

Ever notice that when you bend a string, it is easy to push for some distance, and not much happens to the tone and then it gets a lot harder, and the tone shifts a lot?

This article explains why, but let's see if we can simply the equations a bit. The equation for the force to bend a string to angle theta contains the term (1 - cos(theta))/cos(theta). This is needlessly complicated. As the article states, the angles involved are very small. Therfore it makes sense to approximate the cosine by something else. For really small angles cos(theta) is nearly one. That will do for the demominator. For the numerator, we need to do a bit better, 1 - ((theta)^2)/2. (See Small-angle approximation - Wikipedia, the free encyclopedia. Angle is in radians, not degrees, but never mind, the variation is the same.) Put this all together and the force is just approximately proportional to (theta)^2. That is, the force to move the string a little bit is very small, but it rapidly increase with the square of the angle. This is why it is easy to bend a little bit, but it gets really hard to bend a lot.

Excellent no nonsense investigation and well written article.

And compact to boot, others might have written 200 pages to say the same

[Steve A.]

On a fretted guitar, the string is depressed until it makes contact with the fret marker.Doesn't sound like something earth shattering to me- didn't we all figure that out intuitively 40 or 50 years ago?
The author is an ignorant butcher and should not be encouraged:

Grimes says: 'I took one of my oldest guitars down to the engineering lab at Dublin City University to one of the people I knew there and explained that I wanted to strip it down to do this experiment. We had to accurately bend the strings to different extents and measure the frequency produced. He was a musician too and looked at me with abject horror. But we both knew it needed to be done – We put some nails into my guitar for science.'

So a modern Asian import that was made and set up well would NOT have worked? The guy is a butcher!

Steve A.

EDIT I am responding to the article in the OP link- I just started reading the PLO's one article.

On a fretted guitar, the string is depressed until it makes contact with the fret marker.

This guy is a guitarist?

For the wound strings the author weighed a section of the string to determine its unit weight (UW). I wonder how that compares to the tension charts from d'Addario which I would trust more than an arbitrary figure.

https://www.google.com/url?sa=t&rct=...71778758,d.cGU

Question: Did the author bring up the effect of jumbo and extra jumbo frets on string bending? It has been suggested that with less finger contact with the fretboard is an important factor but I think that there is more metal to raise pitch with the bigger frets.

[Steve A.]

Now *this* is an article that turned my head around as it explained why an LP with a wraparound bridge is more responsive to bends tmore responsive.one with a T-O-M and tailpiece.

Lutherie Myth/Science: Human Perception of String Tension and Compliance in Stringed Musical Instruments

Although the tension is determined by string length, mass and pitch the total length from tuner to tailpiece will determine how easy it is to bend the string on a LP. Ry Cooder has a giant lap steel that takes up a good portion of a room. Imagine a LP nailed to a board with the tailpiece two feet from the bridge. Now imagine trying to bend the 1st string at the 12th fret- you would be pushing against a total string length of 4 feet!

What gets tricky is figuring out how the through-body strings of a tele or a strat would be affected. I think it would depend on the sharpness of angle of the string going into the block. I suspect that tsharp enough angle would prevent any string movement in the block but I could be wrong. A locking nut would eliminate the string length to the tuners. In any case I think a top-mount bridge on a strat or a tele would make it more responsive to string bends...

Steve A.

P.S. Another example is the high E string on a strat compared to one on a LP. Stringing a strat upside down would make string bends more responsive.

EDIT here is a link to the companion article on string tension

http://liutaiomottola.com/formulae/tension.htm

[Mike Sulzer]

Now *this* is an article that turned my head around as it explained why an LP with a wraparound bridge is more responsive to bends tmore responsive.one with a T-O-M and tailpiece.

Did you actually read the article? He did show how nut-to-tuner and bridge-to-tailpiece distances might affect the feel of the string. However the conclusion of the paper is this:

Bob Benedetto's experiments strongly suggest that modifications such as scale length changes and tailpiece length changes intended to provide some difference in string feel may not be very fruitful.

The question of course is whether or not during a string bend the change in tension distributes all along the string. I think it does; this is why people like either low friction nuts, so the process happens very smoothly, or locking nuts, the other extreme, which prevent changes in tension beyond the nut.

I think it is pretty clear that the "extra" lengths do not make much difference in the feel because they really are not very large.

Furthermore, the effects, if significant, are not simple. First, the "extra" length makes the string easier to bend (moves farther for a given force), but you have to move to a greater angle, and provide more total energy, to change the tone by the same amount, that is, you have to provide the energy to change a longer length of string to the same change in tension.

[Mark Hammer]

Just snagged the paper and have to read it later today. But I guess the next step is going beyond the strings themselves and looking at the biomechanics of bending. First up to bat: why is from-above-pull-bending, like the late Jeff Healey would do, more efficient than push-away bending, like the rest of us do. I imagine it would likely have something to do with the decreased force available to the finger tip as it gets extended outward, but that's just a guess off the top of my head.

The next frontier after that is explaining, via string physics, why octave-up fuzzes, and octave-dividers, tend not to give up their magic until around the 7th fret or so.