#1
I have a physics assignment at school on sound waves and technology, I've decided to investigate how an electric guitar works (possibly with effect pedals to make it more interesting). Anyway - I hope this is the right forum ! I'm sure there would be someone on this website that knows alot about this kindof thing, or can point me in the right direction.

Thanks for the help.

Edit: I'm in year 11 so I want to make it fairly indepth.
#2
Do a search, the same question has been asked a couple of times


pickups: read up on induction and magnetism and such

distortion: by overdring an amp past a level where it can no longer amplify it so it just cuts of the tops and bottoms of the signal
or in most solid state amps they use diodes to clip the signal when it goes over past a certain level

other effects: that depends on what they are
http://geofex.com/fxtech.htm
http://www.harmony-central.com/Effects/effects-explained.html
Last edited by seljer at Jun 22, 2006,
#3
distortion and other effects are more in the realm of circuit analysis.

you'd want to focus on guitar physics, look up harmonics (it should be in the sound/waves/oscillation section of your physics textbook). I think it was called fundamental harmonics (1st would be 1/2 of a wave length or a plucked string, 2nd would be a full wave length, or a harmonic at the 12th fret, 3rd would be 1.5 wave lengths or something around a harmonic at the 7th? fret)

Also, for the electro-magnetic portion. Basically the magnets in a pickup put up a magnetic field. The string (usually steel or nickel, which are 2 of the 4 metals that work with magnets, iron and cobalt (i think), being the other 2). As the string vibrates, it changes the electromagnetic flux, inducing an alternating current in the wire at the same frequency the string is vibrating. Regardless of how HARD you pluck it, it won't change the frequency, it'll only change the magnitude of the signal. You should have some equation where the frequency is a function of the tension and length/thickness of the string.

Effects pedal analysis is a bit too complex for a high school level. Explaining overdrive in terms of a circuit and how it works would be a bit too complex as well, atleast in the level that you should explain it for an academics class.
#4
Physics at the age of 11?

Either you're a genius, or you don't live in America.
#6
Make a EQ or a boost pedal. Check this pedal out... You can boost treble or bass, and then you can also boost or cut mids. 3 different switches to use so a bunch of combinations. Also on the site theres charts of the different frequencies and stuff for the different combinations. This should help alot.

http://www.runoffgroove.com/mreq.html
#8
^ um... how is he supposed to analyze that circuit for his physics class?? or at the very least explain the physics of how that pedal works?
#9
Thanks for all the help!

I'm in year 11 in Australia which means I'm 16 and in the second last year of highschool, hahah.

My assignment is going to be based on the physics of the guitar / magnets. I'm only going to have a small section on effects to make it more interesting, because its a speech with a powerpoint I dont want people getting restless.
#10
Quote by greenbox
^ um... how is he supposed to analyze that circuit for his physics class?? or at the very least explain the physics of how that pedal works?


Idn... How would he explain the physics of how any pedal works... lol. I just thought that it would be a little helpful because it was an EQ pedal and showed the graph of the frequencies.
#11
I thought you said it had to be sound waves? If so, then researching an acoustic guitar would be your best bet. If it can be anything physics related, then magnetic fields in pickups would be a good choice.
#12
Dude...I wrote an exam on this for phsyics too! But I got rid of it awhile back, shame I could've sent it to you. Also grade 11. What a coincidence.
#14
Oh make this interesting: have your guitar amped and on hand with whatever effects you're describing. That should keep your audience on the ball.

And it would just be extremely cool.
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#15
Quote by greenbox
^ um... how is he supposed to analyze that circuit for his physics class?? or at the very least explain the physics of how that pedal works?

Electronics is fully contained in physics (well the parts required for guitar and audio circuits are.) It's all basic impedance and amplifier theory...


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#16
yo if you play bring your guitar in and intro your presentation with a short jam or something...that'll be cool.
#17
oh, for my high school physics anyway, we only went over RLC circuits, explaining clipping and other components like transistors wouldn't be relevant to the coursework (atleast that's my take on it)

and essentially, physics covers EVERYTHING, but physics classes dont

good luck on your assignment!
#18
You might also want to meantion Harmonics by the way. Not many people know that that playing the harmonic on the guitar is making a node at the halfway point of the string where the string is not vibrating. Just like in waves... Thats why it works best on the 12th because thats half of your scale length.
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#19
^ yup, fundamental frequencies, as i explained in the 3rd post on this thread