Why are Bridges not straight

J

juststartingout

New member
Why are bridges not parallel with the fret wires. but the intonation is correct?

Shouldn't intonation and scale length be the same for a high E and a low E. As far as I know, the 12th fret should be exactly 1/2 of the scale length.

My SG has a 24 1/2 scale length and the intonation is dead on. On my hi E, the distance from the bridge to the 12th is 12 1/4, right where it should be. On the low E the distance from the bridge to the 12th is 12 1/2, which is 1/4 too long. While I havn't measured the rest of my axes, it seems to be consistant, where the low E is longer than the high E.

Why is this?
 
Different tensions for different strings.
Also the higher strings usually have a lower action (requiring the string to bend less to make contact with the fret, thus requiring less compensation via intonation).
 
Right. You have to bend the string to get it down to the fret. In the same way you bend the string across the fingerboard to raise the pitch bending it down to the fingerboard raises the pitch. The effect that bending has on pitch varies with string thickness, the thinner the string the less it changes. For the wound string the change in pitch is mostly a function of the core, so you usually see the low E longest, A a little shorter, D a little shorter, G long again but usually a little shorter than the low E, B a little shorter, and high E shorter still.
 
beezelbubba said:
Was I wrong or right?It's very important for me to feel that I was right!
Click to expand...
NO!!! YOUR WRONG!!!!!!!!!
"WRONG" I SAY!!!!!!!!!!!!!!!!! :D



































Ok, I guess you could have been onto something there :)
 
beezelbubba said:
Was I wrong or right?It's very important for me to feel that I was right!
Click to expand...

Well shit, I don't know, I asked the question.

I figured it had to do with string size and tension, but I was looking for one of those totally technical answers.

I had to set up a bridge on a tele today and I just set it up with a 1/4" difference and it all worked out. I was just curious as to why.
 
juststartingout said:
I had to set up a bridge on a tele today and I just set it up with a 1/4" difference and it all worked out.
Click to expand...

You can do it more accurately if you have a tuner. Tune the harmonic at the twelth fret to the right note. Check the same string fretted at the twelth fret. If it's sharp make the string longer and if it's flat make the string shorter by adjusting the saddle's position. Repeat as necessary.
 
If you want to know what sounds good....ask a guitar player.
If you want to know why it sounds good...ask a physics professor.
I"ve wondered about it too, but never lost sleep over it.
 
1. Do a search here on "intonation" and you'll get about 500 hits.

2. Read the sections on intonation on any of the books on guitar repair/setup. This issue is thoroughly discussed because it's central to getting guitars to play in tune.

Bridges are slanted because each string is a different gauge, and stretches differently when a note is fretted. The action for each string is never exactly the same as the others on a guitar, and this affects intonation also. Intonation can be adjusted with the help of a tuner, but for a guitar with a non-adjustable bridge you'll need to take it to a repair person.
http://www.1800instruments.com/archive/ghBooks12.htm
http://www.soundinformation.com/books/instrument-repair/0825601568/
I have both these books and they are extremely useful, especially when you are starting out.
 
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