String Height Variation Across Fretboard

[DaveC]

On the guitars I have, as well as the many I have seen and played, I have always wondered why the string height above the fretboard is always higher toward the body end of the fretboard, and lowest toward the nut? I like a low action, and even with the truss adjusted for a flat fret board and the bridge and saddles lowered just above buzzing, or on most every acoustic I have seen, the neck is set so instead of an even string height across the entire fretboard, the strings are at a slight angle (sometimes more than slight) being lower at the nut and higher near the bridge? Question? Is this convention or is there some technical reason? Can a guitar be built with a consistently low string height across the entire fretboard or would that be a poor design for some reason? Before I can get my strings as low as i would like near the bridge I always get string buzz at the lowest frets and the only way to change that would be to have the first couple of frets lower that the rest which seems like a bad idea!

Thanks for the explanation,

DaveC

[killemall8]

On the guitars I have, as well as the many I have seen and played, I have always wondered why the string height above the fretboard is always higher toward the body end of the fretboard, and lowest toward the nut? I like a low action, and even with the truss adjusted for a flat fret board and the bridge and saddles lowered just above buzzing, or on most every acoustic I have seen, the neck is set so instead of an even string height across the entire fretboard, the strings are at a slight angle (sometimes more than slight) being lower at the nut and higher near the bridge? Question? Is this convention or is there some technical reason? Can a guitar be built with a consistently low string height across the entire fretboard or would that be a poor design for some reason? Before I can get my strings as low as i would like near the bridge I always get string buzz at the lowest frets and the only way to change that would be to have the first couple of frets lower that the rest which seems like a bad idea!

Thanks for the explanation,

DaveC

i hate that so much. i want the strings even across the fretboard. you can get the action way lower without buzzing. the only way i have been able to do this is by having no neck angle, and recessing the bridge (tom)

[Prostheta]

Well, technically you can have strings level above a straight-as-a-die adjusted board. This changes when you fret notes however. Having a higher action at the higher end covers a lot of sins such as bad neck relief and bad (or no) fret levelling. It might be it was just set up that way as it's not "wrong"!

Also, when you fret higher up on the board, the angle of the string from the fretted note is slighter over the next fret than it would be from the first position....buzz is more likely, plus "fretting out" when you bend notes.

A better response than mine will follow, hopefully.

[fryovanni]

On the guitars I have, as well as the many I have seen and played, I have always wondered why the string height above the fretboard is always higher toward the body end of the fretboard, and lowest toward the nut? I like a low action, and even with the truss adjusted for a flat fret board and the bridge and saddles lowered just above buzzing, or on most every acoustic I have seen, the neck is set so instead of an even string height across the entire fretboard, the strings are at a slight angle (sometimes more than slight) being lower at the nut and higher near the bridge? Question? Is this convention or is there some technical reason? Can a guitar be built with a consistently low string height across the entire fretboard or would that be a poor design for some reason? Before I can get my strings as low as i would like near the bridge I always get string buzz at the lowest frets and the only way to change that would be to have the first couple of frets lower that the rest which seems like a bad idea!

Thanks for the explanation,

DaveC

There is a very good reason for this. Pluck a string on one of your guitars. Look at the way the string vibrates. Note how much it moves near the nut and bridge saddles. Then look around fret #12. You will see why you need a little more clearance. This is the reason why you can set your string height at the nut to basically the same height as your first fret, and you get no buzzing. While you get fret buzz at higher frets if they are not raised a fair bit(on a dead flat neck you would get fret buzz at around 2/64ths even higher depending on gauge of string and how hard you pick).

Peace,Rich

Edit;

Killemall8-i

hate that so much. i want the strings even across the fretboard. you can get the action way lower without buzzing. the only way i have been able to do this is by having no neck angle, and recessing the bridge (tom)

No neck angle and a recessed bridge will not improve your ability to adjust string height. Neck angle is added to bring the relationship of the strings and a taller bridge right back where they should be.

Prostheta-

Well, technically you can have strings level above a straight-as-a-die adjusted board. This changes when you fret notes however. Having a higher action at the higher end covers a lot of sins such as bad neck relief and bad (or no) fret levelling. It might be it was just set up that way as it's not "wrong"!

Also, when you fret higher up on the board, the angle of the string from the fretted note is slighter over the next fret than it would be from the first position....buzz is more likely, plus "fretting out" when you bend notes.

A better response than mine will follow, hopefully.

You could technically raise the strings higher at the nut, and have equal action down the length of the board. However this would through your intonation off much further than it needs to be. You are right that higher action does of course help string clearance if there are problems with the necks adjustment, or fret level. This ties in with your last comment in the sense that it may help adjust for poor adjustments, but remember you need very very little clearance to avoid buzzing with a well leveled neck(look at the nut height to first fret relation on a neck with low action, extreamly close, but not likely to buzz).

Edited August 28, 2007 by fryovanni

[DaveC]

[fryovanni]

Thanks Rich... and everone else....dah...that makes perfect sense now. The string tension near the nut is higher so less arc as the string vibrates as opposed to near the end on the fretboard which is still far from the bridge, where there is more flex in the strings and therefore more arc and therefore needing more clearance!

With that understanding in mind, to get a little less clearance at the bridge end on a bolt-on neck like on a Strat, could the base of the neck be shimmed in some way underneath so that it changes the angle slighly, closing the gap, or would that be ill advised?

Tension is equal across the length of the string, the only whay to change that would be to bind the string, but that is not the case from the nut to the bridge. I will let one of the physics guru's(there are a handful of those fellas around here that blow my mind with their knowledge) give you more insights into why a string vibrates the way it does.

As far as shimming. Well not exactly, unless you have a problem with the ability to lower your bridge height right now. As long as you can lower the bridge height you can achieve the lowest possible action(neck and fret setup not withstanding). If your nut slots are not set properly(if they are too high or too low), that can limit your ability to set your action low as possible.

Peace,Rich

Edited August 29, 2007 by fryovanni

[soapbarstrat]

i hate that so much. i want the strings even across the fretboard. you can get the action way lower without buzzing.

I'm curious if you are putting this "want" into practice, and what the actual string height measurements are on your neck(s).

I don't see it happening. Comfortable first fret action for me is .015" max on the low E. I want to see someone set their low E .015" at the 12th fret as well. It's going to buzz like hell. Maybe you want the first fret action way up around 1/32" ? Ouch !, that's going to be very uncomfortable to play near the nut.

I see it as the whole fret-board having the "fall away" thing going on. The string vibration increases as you get closer to the body, and also the frets get closer together, which also requires action height to go higher to keep the next fret up from buzzing out your fretted note. Also, as you go up the neck, you are getting closer to where the string is being plucked.

[dh7892]

Tension is equal across the length of the string, the only whay to change that would be to bind the string, but that is not the case from the nut to the bridge. I will let one of the physics guru's(there are a handful of those fellas around here that blow my mind with their knowledge) give you more insights into why a string vibrates the way it does.

Peace,Rich

I'm not sure what you mean by binding the string. If you mean wrapping stuff around it then this will increase the mass per length of string but the binding will not be particularly in tension (it's only the core of a wound sting that's load bearing as I understand it) and so will not affect the tension of the string (except that the whole string will need to be a bit tighter to get it up to pitch).

Binding the sting with different mass per unit length as you move along the string (ie thicker binding at the bridge end) would affect the formation of the standing waves on the string when it was plucked. I think this would be pretty weird and hard to tune/get the intonation right.

[fryovanni]

Tension is equal across the length of the string, the only whay to change that would be to bind the string, but that is not the case from the nut to the bridge. I will let one of the physics guru's(there are a handful of those fellas around here that blow my mind with their knowledge) give you more insights into why a string vibrates the way it does.

Peace,Rich

I'm not sure what you mean by binding the string. If you mean wrapping stuff around it then this will increase the mass per length of string but the binding will not be particularly in tension (it's only the core of a wound sting that's load bearing as I understand it) and so will not affect the tension of the string (except that the whole string will need to be a bit tighter to get it up to pitch).

Binding the sting with different mass per unit length as you move along the string (ie thicker binding at the bridge end) would affect the formation of the standing waves on the string when it was plucked. I think this would be pretty weird and hard to tune/get the intonation right.

Binding/Pintching/Increase friction to the point that you do not allow it to move/locking. This is what I was refering to.

However, you bring up an interesting subject in string construction. Winding material around a core allows us to use similar string tension and have strings with greater density(mass/weight), while at the same time maintaining a good degree af flexability. You are absolutely right that altering the density along the length would not be a good thing, also altering the flexability along the length is a bad thing.

Good thoughts.

Peace,

Rich

[dh7892]

Binding/Pintching/Increase friction to the point that you do not allow it to move/locking. This is what I was refering to.

However, you bring up an interesting subject in string construction. Winding material around a core allows us to use similar string tension and have strings with greater density(mass/weight), while at the same time maintaining a good degree af flexability. You are absolutely right that altering the density along the length would not be a good thing, also altering the flexability along the length is a bad thing.

Good thoughts.

Peace,

Rich

I can think of two possible reasons why one MIGHT want to experiment with different mass distributions along a string (but I'm not sure how much they would work):

1. To compensate for intonation (but you'd have to custom make each string for the guitar in question and I'm not even sure it would work anyway
   
2. By having the last cm or so of the sting (near the bridge) having continuously increasing mass, you would create less of an impedance mismatch at the bridge (although this would probably allow more energy to be absorbed by the bridge and hence reduce sustain)
   

Just some wacky ideas, like you say it's a bit of a crazy thing to do. If you vary the mass over the whole string, I doubt you'd even get a sinusoidal looking waveform on the string. I suppose that different pickup positions might end up "hearing" different pitches.

Anyway, sorry if I've gone a bit off topic, I'll shut up now.

[fryovanni]

Binding/Pintching/Increase friction to the point that you do not allow it to move/locking. This is what I was refering to.

However, you bring up an interesting subject in string construction. Winding material around a core allows us to use similar string tension and have strings with greater density(mass/weight), while at the same time maintaining a good degree af flexability. You are absolutely right that altering the density along the length would not be a good thing, also altering the flexability along the length is a bad thing.

Good thoughts.

Peace,

Rich

I can think of two possible reasons why one MIGHT want to experiment with different mass distributions along a string (but I'm not sure how much they would work):

1. To compensate for intonation (but you'd have to custom make each string for the guitar in question and I'm not even sure it would work anyway
   
2. By having the last cm or so of the sting (near the bridge) having continuously increasing mass, you would create less of an impedance mismatch at the bridge (although this would probably allow more energy to be absorbed by the bridge and hence reduce sustain)
   

Just some wacky ideas, like you say it's a bit of a crazy thing to do. If you vary the mass over the whole string, I doubt you'd even get a sinusoidal looking waveform on the string. I suppose that different pickup positions might end up "hearing" different pitches.

Anyway, sorry if I've gone a bit off topic, I'll shut up now.

Please elaborate on how you would go about adjusting mass(where would you add or subtract?). I am curious as to how that would work as you fret up the neck. I am not sure about the impeadance mismatch, but here is a little food for thought on a low B bass string construction option-link. I would love to hear more of your thoughts. If you want to get a good chat going on your ideas. Fire up a new topic, and we can hash out some ideas.

Peace,Rich