Ok, stupid question, but how should the bridge be adjusted for the intonation? what effect does all of the little adjustment screws on guitars have on the sound? and why? Doesn't moving them make your fretted notes out of tune?
I am happy to read a long and exhaustive lecture about how al of this works-so don't shorten anything.

its like messing up the scale of the guitar. lest supose a guitar has a 25" scale. this way the 12th fret is at the exact middle (12.5") and the harmonic of the 12th fret is at the same point. both must sound in the same note.

however, if you use a diferent string gauge, the harmonic point might move a bit and therefore your harmonic may move a bit from the 12th fret to the begining of the 13th, or to middle 11th or half 12th instead of the exact end between 12 and 13. so you need to adjust the bridge to accept the new gauge with its natural intonation and scale. the notes move along with the harmonic. that is why when adjusting intonaton you need to check your harmonic note is the same as the fretted 12th fret note. if they are the same, the rest of the notes are too.

if you dont understand something that i said, just ask. this was tiped very fast.

Last edited by ldnovelo at Aug 12, 2008,
thanks alot, that really helped. how can I do this accurately? and do you have any more info on the subject? With a tune o matic bridge (and others i'm sure) I need to take the string off (or loosen it loads) adjust the screw, and put it back on, so isnt this really difficult to do?
just been thinking, if you move the moveable thing in the bridge (what's it called?) then wouldn't that just put the fretted note out of tune but have a harmonic in tune?