#1
I dunno, I had this question for a while..

What is the reason bending alters the pitch of the sound?
Is it because you are applying more tension to the string (like whenever you go further in the bend, you apply more tension and thus the pitch rises)?
Or is it because the distance you bend it (independant of tension, maybe if you alter the lenght of the string somehow)?
#2
You're shortening the string, sort of.

When you play the first fret of the B string, it is C because the diatance between the fixed point and the bridge is no longer nut to bridge, but C to bridge. Thus, the string is shorter and the pitch is getting higher.

When you bend, you are tightening the string, which makes it shorter and then it's the exact same idea as above.

For those of you who don't know how to bend:
http://www.cyberfret.com/techniques/index.php
#3
But how do you get the string shorter if you are "holding" one end of it (the C in this case, which you bend) and the other end is fixed?

I would say you apply more tension to it, since the string is also tied to the nut which applies some tension, so if you bend perpendicular to it, you apply even more tension (kind of like using Pythagora's Theorem)? (I don't know a lot of wave physics though)
#5
Quote by bangoodcharlote
How much do you remember about vectors and mechanics?


Well, I remember that since it is kind of what I've been learning all this year

But if the nut applies tension (horizontal), and you apply tension (perpendicular), then the tension resulting is greater, and thus the pitcher higher...
Is that right?
#7
Quote by gonzaw
But if the nut applies tension (horizontal), and you apply tension (perpendicular), then the tension resulting is greater, and thus the pitcher higher...
Is that right?
Yes.

And you've just saved me from having to give a vector-physics lecture on a weekend!

Quote by branny1982
the string does not get shorter. the string actually gets stretched if anything!
That was poorly phrased on my part, but to explain myself involves vector-physics, which I really don't want to do right now.
#8
theres a physical formula somewhere for a string where the pitch of vibration is a function of the:
  • thickness of the string
  • length of the string
  • material of the string
  • tension of the string

go ask your physics teacher

I'd say the important one here is tension
#9
Quote by bangoodcharlote
Yes.

And you've just saved me from having to give a vector-physics lecture on a weekend!
.


Right
I just wasn't sure how tension would apply to bending (but then I remembered sum of vectors)

Quote by quinny1089
increasing tension on the string does not mean you are making the string shorter.

Their are 2 ways to alter the pitch of a string.
Change length, ie. fretting
or change the tension ie. turning tuning knobs, string bending.


You forgot changing the density

Which is kind of useless since you already have different strings with different density in the guitar..

Quote by seljer
theres a physical formula somewhere for a string where the pitch of vibration is a function of the:
  • thickness of the string
  • length of the string
  • material of the string
  • tension of the string

go ask your physics teacher

I'd say the important one here is tension


Couldn't you just say that as density?
Like thickness=volume and material=mass? (if you change one of those you are already changing the density, unless you are doing it proportionally, meaning it doesn't change the pitch)
Last edited by gonzaw at Sep 13, 2008,
#10
Quote by gonzaw

Couldn't you just say that as density?
Like thickness=volume and material=mass? (if you change one of those you are already changing the density, unless you are doing it proportionally, meaning it doesn't change the pitch)


well...yes.....butl you're probably not going to vary your alloy of metal over the same set of strings
eg: the unwound strings on a regular set for an electric

so its either just the thickness of the string or the whole shebang (like for a nylon string guitar or something)


hmm....how about doppler effect bending? run towards the audience fast enough that they hear a shift in pitch
or if we've got an electric guitar, general theory of relativity bending

Quote by quinny1089
well i meant 2 ways you personally (as a player) can do to change the pitch lol

i suppose heating would alter the density of a material(dont quote me...i know nothin about chem)...so technically setting your guitar alight a la Jimi would work...but i'm sure it would hinder your playing to some extent


heating makes a long piece of metal expand lengthwise, so yeah, I guess that also includes density (but I think its the stretching that will make it more of the effect)


edit:
http://en.wikipedia.org/wiki/Vibrating_string
Last edited by seljer at Sep 13, 2008,
#11
Quote by seljer
hmm....how about doppler effect bending? run towards the audience fast enough that they hear a shift in pitch
Stick a jet engine on your amp, fasten in to a track, and then have a stopper at the end of the stage.

What's scary is that I could have figured out how to achieve the desired pitch in that scenario at one point, and it wouldn't even be a ridiculous question (aside from the practicality of the actual event) on a physics exam.
#12
Quote by bangoodcharlote
Stick a jet engine on your amp, fasten in to a track, and then have a stopper at the end of the stage.

What's scary is that I could have figured out how to achieve the desired pitch in that scenario at one point, and it wouldn't even be a ridiculous question (aside from the practicality of the actual event) on a physics exam.


I once got bored and took my mp3 player and recorded the sound of cars passing by on the highway
then at home I looked at the spectrogram of it an calculated how fast the cars were going from the shift in frequencies
#13
Quote by seljer
I once got bored and took my mp3 player and recorded the sound of cars passing by on the highway
then at home I looked at the spectrogram of it an calculated how fast the cars were going from the shift in frequencies
Major nerd alert! But I like it!

You could only do that on a street with one car going by at a time, though, otherwise the interference of the other cars would create a great big mess.


I suppose it's better than drinking a Dasani, sticking a bunch of dry ice in it, putting some more water in in, sealing the cap, throwing it in the corner of a parking garage, and then taking cover behind a BMW.
Last edited by bangoodcharlote at Sep 13, 2008,
#14
Quote by bangoodcharlote
Stick a jet engine on your amp, fasten in to a track, and then have a stopper at the end of the stage.

What's scary is that I could have figured out how to achieve the desired pitch in that scenario at one point, and it wouldn't even be a ridiculous question (aside from the practicality of the actual event) on a physics exam.


Ridiculous question ehh?:

You have a 15 grams string made of steel, and you play a 456 hz note when shortening the string to 3/2 its lenght.
a) What would you do to play the intro of Ode to Joy?
b) If you break your string in half, and you can't add more tension to it becase it can break even more, and you only have an oven and 100 grams of iron and 50 grams of liquid carbon, how can you play the same piece?




Quote by seljer

I once got bored and took my mp3 player and recorded the sound of cars passing by on the highway
then at home I looked at the spectrogram of it an calculated how fast the cars were going from the shift in frequencies


Wow that's cool...