Why are some acoustic guitar bridges crooked? - Tilted Forum Project Discussion Community

Jimellow · 11-04-2008, 09:55 AM

I noticed that the bridge of my guitar, as well as others I've seen pictures of (even expensive ones), have crooked bridges. Why is this?

Initially I thought it was a manufacturing defect with mine, but after seeing others with similarly set bridges, it piqued my interest.

Also, are guitar bridges glued/fastened to the body, or can they be moved when the strings are loosened/removed?

ratbastid · 11-04-2008, 12:39 PM

When you say "crooked", you mean the bridge is set at something other than a 90-degree angle to the strings?

I'd bet the bridge is set the way it is for intonation reasons. Guitar intonation adjustment is a black art that I have only a sketchy understanding of... others will be better equipped to comment, I think.

allaboutmusic · 11-04-2008, 01:00 PM

ratbastid is absolutely right. A string vibrates between its two fixed endpoints, and by fretting the string, you shorten the string and change the vibrating length and therefore the pitch.

In theory an open string vibrates between the two points exactly where it leaves the nut (at the headstock end) and the saddle (the bridge end). In practice though, the thickness and stiffness of the string play a part in it. Think about it this way - if you hold a ruler down against the edge of the table and pull it so it vibrates, its rotational point is a short distance from the edge of the table. The thicker and/or stiffer the ruler, the further away this point is.

The "crooked" bridge is an attempt to compensate for the different thicknesses of the strings. For this reason, thicker strings have to have more compensation than thinner strings.

Aha, you say - but then why does the compensation reduce between the wound and unwound strings? The reason is that wound strings are an attempt to reduce the stiffness of the string. The string is still thick, so gets lower-pitched notes, but because the outer layer is wound the whole thing is less stiff and therefore needs less compensation.

Does that sort of make sense?

Derwood · 11-04-2008, 04:42 PM

then there are the guitars with a symmetrical frets:

11-04-2008, 09:55 AM	#1 (permalink)
Jimellow Junkie	Why are some acoustic guitar bridges crooked? I noticed that the bridge of my guitar, as well as others I've seen pictures of (even expensive ones), have crooked bridges. Why is this? Initially I thought it was a manufacturing defect with mine, but after seeing others with similarly set bridges, it piqued my interest. Also, are guitar bridges glued/fastened to the body, or can they be moved when the strings are loosened/removed? __________________ Desperation is no excuse for lowering one's standards.

11-04-2008, 12:39 PM	#2 (permalink)
ratbastid Darth Papa Location: Yonder	When you say "crooked", you mean the bridge is set at something other than a 90-degree angle to the strings? I'd bet the bridge is set the way it is for intonation reasons. Guitar intonation adjustment is a black art that I have only a sketchy understanding of... others will be better equipped to comment, I think. Last edited by ratbastid; 11-04-2008 at 12:39 PM.. Reason: darn spelling

11-04-2008, 01:00 PM	#3 (permalink)
allaboutmusic Aurally Fixated	ratbastid is absolutely right. A string vibrates between its two fixed endpoints, and by fretting the string, you shorten the string and change the vibrating length and therefore the pitch. In theory an open string vibrates between the two points exactly where it leaves the nut (at the headstock end) and the saddle (the bridge end). In practice though, the thickness and stiffness of the string play a part in it. Think about it this way - if you hold a ruler down against the edge of the table and pull it so it vibrates, its rotational point is a short distance from the edge of the table. The thicker and/or stiffer the ruler, the further away this point is. The "crooked" bridge is an attempt to compensate for the different thicknesses of the strings. For this reason, thicker strings have to have more compensation than thinner strings. Aha, you say - but then why does the compensation reduce between the wound and unwound strings? The reason is that wound strings are an attempt to reduce the stiffness of the string. The string is still thick, so gets lower-pitched notes, but because the outer layer is wound the whole thing is less stiff and therefore needs less compensation. Does that sort of make sense?

11-04-2008, 04:42 PM	#4 (permalink)
Derwood Who You Crappin? Location: Everywhere and Nowhere	then there are the guitars with a symmetrical frets: