my research project "distortion pedals"

[Chef]

Below is a link to the research project i have just finished for my final year research project at uni.  Thought some of you guys might find it an interesting read.  Please take everything i say in it with a pinch of salt.  I may even have quoted from some of you but all the quotes are referenced.  A lot of it is just introducing the basics which most of you will find boring and you may even read bits that you think are wrong.  I went into this as a complete beginer and still am today so i will take any criticism as a positive thing.  I posted a lot of questions on this forum during the making of this project and i have a lot of you guys to thank for helping me get unstuck in certain places. 

Please be gentle with me

Adam

http://www.diystompboxes.com/DIYFiles/up/Adam_Horrell_Research_Project.pdf

[DuncanM]

When the electric guitar was invented by Les Paul

Hamm also states that valve amplifiers will exhibit more bass than transistor based equivalents.  This
is directly related to their strong 1st and 3rd harmonics, which reinforce natural bass with synthetic bass.

Surely 2nd and 3rd harmonics?

Hamm ignores the idea of a 1st harmonic,
which is generally considered to be an octave above the fundamental.

No, the first harmonic IS the fundamental. The second harmonic is one octave above.

At this point I have to stop otherwise I'll become confused and angry. Sorry.

[Chef]

The sources that i got all that information from are referenced so you can check them out if you want.  This isn't something i just made up off the top of my head.

Adam

[DuncanM]

Sorry Adam, I didn't mean to be a negative but this confusion over 1st harmonic/2nd harmonic is a bit of a problem.

The expression "generally considered" is a loaded one and I would like to know where you got THAT from. It sort of turns the whole analysis on it's head and could confuse the hell out of the person who's got to grade your report.
Especially if, like me, they generally consider Russell Hamm's view to be the correct one...

Analysis of the different Transfer Functions of the various diodes and the different non-linearities they introduce is the key.
Asymmetric clipping to simulate valves?
Comparison with hard clipping distortion?

Have you submitted it yet?

[wampcat1]

Good read! Looks like you put some *serious* time into it! : )

Also, thanks for the plug in the references. 

[Chef]

I have submitted it but i am interested in the subject so any suggestions will be taken onboard and i might create a revised edition for my own benefit.

Adam

[Mark Hammer]

I'm just kind of taken aback that you might actually have instructors who would accept material on such a topic.  A bit like submitting a philosophy dissertation on "The semiotics of WWF wrestling".  Not wrong or bad, just....not what the prof was expecting.

[jrc4558]

"The semiotics of WWF wrestling" - ROTFLOL

[dano12]

This is a really nice piece of research and writing.--you've obviously put a lot of work into it. Thanks very much for sharing this with the community. I'm going to read it cover to cover tonight.

[Chef]

I'm pleased you all find it interesting, thanks for the comments, makes me feel that the last 6 months haven't been a total waste of time.

Adam

[Paul Perry (Frostwave)]

"The semiotics of WWF wrestling" - ROTFLOL

http://www.mellenpress.com/mellenpress.cfm?bookid=5487&pc=9
I'm afraid that is just one of the many books devoted to the semiotics of WWF wrestling.
(No, I couldn't make up this stuff either. Modern academia transcends satire.)
Give me essays on distortion any day! But as you can see, it's pretty difficult to formalise the perception of the musiclity (or otherwise) of distortion...

[TELEFUNKON]

what a labour, Chef!
(and the first time in such a case, that "R.G." or "geofex" isn`t mentioned in the bibliography).

[Chef]

Not heard of either of those, do you think it's something i should've read?  I'll look into them,

Adam

[wampcat1]

Not heard of either of those, do you think it's something i should've read?  I'll look into them,

Adam

Absolutely...there wouldn't be NEAR the interest in DIY effects had it not been for RG (www.geofex.com), Jack (www.muzique.com), Aron (diystompboxes.com of course) and many of the well known names here.

bw

[Gilles C]

Nice work. Will have to read and check a few things more like about the harmonics thing.

I liked the note about using GE diodes for Blues, Blues being my style. Normally, it's not mentioned a lot in distortion projects...

G.

[tiges_ tendres]

I'm just kind of taken aback that you might actually have instructors who would accept material on such a topic.  A bit like submitting a philosophy dissertation on "The semiotics of WWF wrestling".  Not wrong or bad, just....not what the prof was expecting.

Roland Barthes wrote a nice piece on wrestling.  well, french wrestling, anyway.  And from the 1950's

http://social.chass.ncsu.edu/wyrick/debclass/rbwres.htm

[syndromet]

Learned a lot from this.

[Chef]

I did confuse things a little with the section on harmonics.  After reading another book recently called the science of musical sound it was made clear that you can look at harmonics/overtones in different ways.  Some people call the 1st the 2nd and visa versa but as long as people know exactly what you mean when you say "the 1st harmonic" then it doesn't really matter.  In my project the order is as follows:

using an example of 100Hz fundamental

Fundamental - 100 Hz
1st Harmonic - 200 Hz
2nd Harmonic - 300Hz
3rd Harmonic - 400Hz

Hamm (my main source) uses the following order

1st harmonic - 100 Hz
2nd Harmonic - 200Hz
3rd Harmonic - 300Hz
etc.

i ammended any quotes from his paper to fit into my way of thinking.

Hope this clears that section up as it's quite important to the understanding of the whole paper. I didn't write that section very well.

I'm really pleased people are getting something out of reading it, thanks for all the comments

Adam

[DuncanM]

Fair enough, but when you are approaching this from an "Engineering" perspective it becomes very important that everyone is using the same terms.
Especially when doing distortion measurements - you'll see THD (total harmonic distortion), 2nd and 3rd harmonic distortion, but I've yet to see a 1st harmonic distortion figure quoted anywhere ('cos there aint no such thang).....
Also when doing fourier analysis. <Mmmmm>.

Also, being a pedant, I would take issue with Les Paul "inventing" the electric guitar. Lloyd Loar, Vic Smith, George Beauchamp and Adolph Rickenbacker all have good claims for that while Les was still in his early teens - and they had the patents...
Les was quite an inventor but I wouldn't credit him with the electric guitar.

[Mark Hammer]

I'm just kind of taken aback that you might actually have instructors who would accept material on such a topic.  A bit like submitting a philosophy dissertation on "The semiotics of WWF wrestling".  Not wrong or bad, just....not what the prof was expecting.

Roland Barthes wrote a nice piece on wrestling.  well, french wrestling, anyway.  And from the 1950's

http://social.chass.ncsu.edu/wyrick/debclass/rbwres.htm

Actually, the semiotics of wrestling IS a fascinating topic, and Barthes was a hell of a writer (and godfather of semiology).  So, I was only feigning an outrageous topic.

In a similar way, there is no reason why the deliberate planful introduction of harmonic distortion could not be every bit as academic a topic as the elimination of harmonic distortion in signal processing.  After all, whether you make it go away or whether you make it occur in shovelfuls, you have to grasp the same principles, don't you?