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  #1  
Old 01-22-2018, 02:22 PM
RockyRacc00n RockyRacc00n is offline
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Default saddle height question

I hope I can describe this without pictures.

The question is regarding the saddle height and the resulting angle in which the string exits the pin hole.

So, the higher the saddle, the more obtuse the angle is at which the string exists the pin hole. Conversely, the lower the saddle, the more acute the angle is at which the string exits the pin hole.

And my question is, if the saddle is too low, and the angle at which the string exits the pin hole is too acute, do you need to worry about the long term effect of the string cutting into the bridge too much as it exits the pin hole? Especially the high E string (thinnest, thus exerting the most cutting pressure against the bridge material)
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Old 01-22-2018, 02:41 PM
YamahaGuy YamahaGuy is offline
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To alleviate the problem of having too shallow (acute) an angle, which can create a sitar sound and result in not enough downward pressure of the string on the saddle to get a good tone, many times the pin holes are slotted.

http://www.stewmac.com/How-To/Online..._Slotting.html

I've done this to my guitars where the break angle is questionable.

So to answer your question, I would be less concerned about the string damaging the bridge and more concerned with getting the angle right to get the best tone.
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  #3  
Old 01-22-2018, 03:48 PM
RockyRacc00n RockyRacc00n is offline
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Quote:
Originally Posted by YamahaGuy View Post
To alleviate the problem of having too shallow (acute) an angle, which can create a sitar sound and result in not enough downward pressure of the string on the saddle to get a good tone, many times the pin holes are slotted.

http://www.stewmac.com/How-To/Online..._Slotting.html

I've done this to my guitars where the break angle is questionable.

So to answer your question, I would be less concerned about the string damaging the bridge and more concerned with getting the angle right to get the best tone.
I see. So it seems there is a tonal effect... not that I noticed. I was more concerned about increased cutting pressure against the bridge, which sounds like is not a concern... and in fact, it looks like this tool is made to cut into the bridge, the very thing I was worried about happening. But I don't quite understand what that slot is supposed to do?
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Old 01-22-2018, 05:56 PM
YamahaGuy YamahaGuy is offline
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Quote:
Originally Posted by RockyRacc00n View Post
I see. So it seems there is a tonal effect... not that I noticed. I was more concerned about increased cutting pressure against the bridge, which sounds like is not a concern... and in fact, it looks like this tool is made to cut into the bridge, the very thing I was worried about happening. But I don't quite understand what that slot is supposed to do?
The slot creates a lower ramp for the string to approach the saddle from a lower spot which allows for a steeper break angle over the saddle. Imagine a 7' tall person holding a rope that is anchored to the top of an 8' wall while standing 20' away. Then imagine that 7' tall person holding the same rope while sitting on the ground still 20'away. Same idea.
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  #5  
Old 01-22-2018, 09:38 PM
RockyRacc00n RockyRacc00n is offline
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I think I get it. The result being greater downward pressure on the saddle.
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Old 01-22-2018, 10:34 PM
John Arnold John Arnold is offline
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Quote:
do you need to worry about the long term effect of the string cutting into the bridge too much as it exits the pin hole?
The short answer is no.
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Old 01-23-2018, 04:50 AM
YamahaGuy YamahaGuy is offline
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Quote:
Originally Posted by RockyRacc00n View Post
I think I get it. The result being greater downward pressure on the saddle.
That's it.
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  #8  
Old 01-23-2018, 11:18 AM
Alan Carruth Alan Carruth is offline
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I can see your concern for avoiding having the string cut into the bridge; As John Arnold says, it's pretty much hypothetical. The real issue is with the other side of this, the break angle over the saddle, and the load that puts on the saddle and the bridge.

You do, of course, need some break angle, so that the string will make good contact all through it's vibration cycle and 'know' how long it is. I've done an experiment with very low break angle, down to about 6*, and found that to be 'enough' if the string is plucked so that it starts out moving 'vertically'. Given that there is some horizontal (relative to the soundboard) motion in a normal pluck you need a bit more break angle to keep the string from 'rolling' on the saddle top; 12*-15* should do.

The experiment I did looked at both string height off the top and break angle over the saddle independently. What I found was that changing the break angle by itself did not change the sound of the guitar in any way that could be measured or heard. Changing the string height off the top did change the sound.

The string breaking over the top of the saddle produces a down force along a line that bisects the break angle. There is a downward component, and also one that pushes the top of the saddle forward, trying to tip it over. That's one reason we put the saddle in a slot, unlike, say, a violin, where the bridge more or less bisects the break angle, and doesn't tend to tip forward if you keep it all properly adjusted. The greater the break angle, the greater the tipping force. This can, in some cases, be enough to break out the front of the slot. Even when it doesn't it can cause the wood to distort, making the slot wider, and the saddle fit looser, in the middle.

There is one possible benefit of increasing the break angle; it does put more down force on an under saddle transducer. These seem to work better with more down force. You can get the same effect from angling the saddle slot back, as seen from the side. Setting it up so that the saddle bisects the break angle is the best of all possible worlds; you maximize the down force on the UST, and zero out the tipping force trying to break out the saddle slot. Usually this is not possible as a retrofit.
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Old 01-30-2018, 09:55 AM
RockyRacc00n RockyRacc00n is offline
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Quote:
Originally Posted by Alan Carruth View Post
I can see your concern for avoiding having the string cut into the bridge; As John Arnold says, it's pretty much hypothetical. The real issue is with the other side of this, the break angle over the saddle, and the load that puts on the saddle and the bridge.



You do, of course, need some break angle, so that the string will make good contact all through it's vibration cycle and 'know' how long it is. I've done an experiment with very low break angle, down to about 6*, and found that to be 'enough' if the string is plucked so that it starts out moving 'vertically'. Given that there is some horizontal (relative to the soundboard) motion in a normal pluck you need a bit more break angle to keep the string from 'rolling' on the saddle top; 12*-15* should do.



The experiment I did looked at both string height off the top and break angle over the saddle independently. What I found was that changing the break angle by itself did not change the sound of the guitar in any way that could be measured or heard. Changing the string height off the top did change the sound.



The string breaking over the top of the saddle produces a down force along a line that bisects the break angle. There is a downward component, and also one that pushes the top of the saddle forward, trying to tip it over. That's one reason we put the saddle in a slot, unlike, say, a violin, where the bridge more or less bisects the break angle, and doesn't tend to tip forward if you keep it all properly adjusted. The greater the break angle, the greater the tipping force. This can, in some cases, be enough to break out the front of the slot. Even when it doesn't it can cause the wood to distort, making the slot wider, and the saddle fit looser, in the middle.



There is one possible benefit of increasing the break angle; it does put more down force on an under saddle transducer. These seem to work better with more down force. You can get the same effect from angling the saddle slot back, as seen from the side. Setting it up so that the saddle bisects the break angle is the best of all possible worlds; you maximize the down force on the UST, and zero out the tipping force trying to break out the saddle slot. Usually this is not possible as a retrofit.


I think I understand most of what you said. Would it be correct to say that you are confirming what was said prior but with more of an experimental analysis you did?

That is, the concern should be more about the downward pressure on the saddle than the increased cutting pressure by the string (especially the thin ones) on the bridge material?

I didnít include a picture before but here it is.

Few shots of the saddle





I needed this saddle height to achieve nickel height action on the low E and a penny height action on the high E. Donít have a fine ruler nor the good eye sight to measure in 1/32 inch increments.





This is on a new Martin D18 so Iím pretty sure the neck is straight so felt Ok about sanding down the saddle to get the action I wanted. But as stated before, after sanding it down and seeing how low it sat in the bridge, I wasnít sure if this is typical or something to be concerned about.

I just wanted to ask the question again, this time with some pictures.
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Old 01-30-2018, 10:57 AM
Guest 1928
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Quote:
Originally Posted by RockyRacc00n View Post
...I needed this saddle height to achieve nickel height action on the low E and a penny height action on the high E. Donít have a fine ruler nor the good eye sight to measure in 1/32 inch increments...
No doubt you did need the saddle that low. However, a nickel is about 0.075" and a penny about 0.060". That is ridiculously low action for an acoustic guitar. The guitar wasn't designed for that kind of setup, so it does force you to have a saddle that is lower than would be ideal.
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Old 01-30-2018, 11:12 AM
RockyRacc00n RockyRacc00n is offline
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Originally Posted by Todd Yates View Post
No doubt you did need the saddle that low. However, a nickel is about 0.075" and a penny about 0.060". That is ridiculously low action for an acoustic guitar. The guitar wasn't designed for that kind of setup, so it does force you to have a saddle that is lower than would be ideal.


I see. Yes. I was wondering about that too... if I am lowering too much. Before getting this D18, I was used to my DRS2 which wasn’t adjusted at all but has the action I specified with the saddle sitting up higher. (Wondering if there was some sinking of the top due to lack of moisture on the DRS2, even though I tried to keep it humidified?)

Anyway, I was going for the same action on the D18 but then it resulted in this saddle height. I don’t normally play up in the higher frets that much so maybe it’s more about me getting more proficient at fretting on the higher frets but being used to such action coming from the DRS2, I wanted to try the same action on the D18.

The basic rule I am familiar with is, get it as low as you can without it buzzing when strummed as normally played. Is there something else that should be considered? You said the D18 wasn’t designed for this low of an action. I wonder what you mean by that.

Last edited by RockyRacc00n; 01-30-2018 at 11:21 AM.
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Old 01-30-2018, 11:25 AM
Guest 1928
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Quote:
Originally Posted by RockyRacc00n View Post
The basic rule I am familiar with is, get it as low as you can without it buzzing when strummed as normally played.
That is generally correct, and the action you have would not tolerate what I would consider normal playing without buzzing.

Quote:
Originally Posted by RockyRacc00n View Post
You said the D18 wasn’t designed for this low of an action. I wonder what you mean by that.
Let's ignore any tonal considerations and just look at the geometry. Martin expects a higher action, so bridge height, saddle height, and neck angle are chosen collectively to meet a particular action height. Someone who wants a very low action would need the neck set at a steeper angle to accomplish than, while maintaining the bridge and saddle height. Someone who wants a very high action would need to do the opposite. Martin (or any manufacturer) would generally choose a middle-of-the-road setup as their default.

If you set this action up closer to 0.090" low E and 0.070" high E, you'd have a much more reasonable looking saddle. And I'm making a leap here and accepting that the relief is more or less correct. Relief should not be used to adjust the action, but it does affect it.

Last edited by Guest 1928; 01-30-2018 at 01:48 PM.
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  #13  
Old 01-30-2018, 12:24 PM
RockyRacc00n RockyRacc00n is offline
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Originally Posted by Todd Yates View Post
If you set this action up closer to 0.090" low E and 0.70" high E, you'd have a much more reasonable looking saddle.
I think you meant 0.070 on the High E, but I get what you mean on the rest of your response.

I have a new saddle so something to play with.

Quote:
Originally Posted by Todd Yates View Post
And I'm making a leap here and accepting that the relief is more or less correct. Relief should not be used to adjust the action, but it does affect it.
Yes, it's a new guitar. And I tried that method where you fret down the 1st and 12th and look for very small gap at the about the mid point. And that looked OK.
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