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  #1  
Old 09-30-2018, 01:47 AM
capefisherman capefisherman is offline
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Default Break angle on saddle, affect on tone/volume?

Does a low saddle transmit the string vibration to the bridge and the top less efficiently than a tall saddle?
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Old 09-30-2018, 03:10 AM
Paddy1951 Paddy1951 is offline
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In a word, yes. This is why many guitars eventually need neck resets. They become too hard to fret and lose a lot of their oomph. (A very technical term, lol.)
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Old 09-30-2018, 03:20 AM
thegazza thegazza is offline
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I've got a Martin that's had low saddle height and minimal break angle for many years. It's the best sounding and playing acoustic that I've heard or played.

Gazza
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Old 09-30-2018, 03:29 AM
D-utim D-utim is offline
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If the guitar has been set up properly, then low saddle height and break angle will have little or no impact on tone.
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Old 09-30-2018, 03:32 AM
Wade Hampton Wade Hampton is offline
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The height of the saddle and its break angle do have an impact on both tone and volume, to an extent. This is why bluegrass guitarists often have their saddle height pretty high, just so the guitar will cut through better in purely acoustic jam session situations.

Naturally, this reaches a point of diminishing returns fairly quickly. But if the player is willing to sacrifice some playability in exchange for greater projection and “cut,” that’s one common way of doing it.

Hope that makes sense.


Wade Hampton Miller
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Old 09-30-2018, 03:37 AM
cuthbert cuthbert is offline
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Yes it's physics, the bigger the angle is the more the vertical component loads the saddle.
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Old 09-30-2018, 04:12 AM
dneal dneal is offline
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It’s the height of the saddle, not the “break angle” from the saddle to the pin.

A saddle works as a lever, with the strings applying torque to the top. A taller saddle is a longer lever - giving more torque. There’s a limit to how much stress the saddle, bridge and top can handle; and 1/2” above the top seems to be the “ideal” height.

The break angle from the saddle to pin (or anchor point if a pinless bridge) is just a consequence of anchor location relative to the saddle. If it were as vital as some believe, you wouldn’t see so much variation. Some pin locations are parallel to the saddle. Some are parallel to the bridge. Some are in a ‘u’ shape, and some (particularly pinless systems) have a much less acute angle.

The neck angle can (and should) be set to give good playability with the appropriate amount of height at the saddle. In a perfect world, you would adjust the neck angle instead of sanding the saddle to get good playability. With a fixed neck, that’s not cost effective. Taylor’s shim system and other makers’ adjustable necks are an attempt at this.
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Old 09-30-2018, 04:37 AM
cuthbert cuthbert is offline
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Quote:
Originally Posted by dneal View Post
It’s the height of the saddle, not the “break angle” from the saddle to the pin.
If the pins were positioned at the same height of the saddle the vertical component of the force would be 0 and you would have 0 vertical load on the saddle itself.

On the other side you can have a low saddle but if the pins are even lower you will have more vertical force than with higher pins, it's like a bowed instrument with tailpiece.



If the tailpiece were on the same plan as the saddle no vertical force on the top....and that was the reason why in the early XIXth they converted almost all what we call today "baroque" violins with horizontal neck to the current configuration with a neck angle, it allowed to install a highger bridge and therefore more volume due to the fact the angle of the tailpiece had increased.
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Old 09-30-2018, 04:53 AM
pszy22 pszy22 is offline
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Quote:
Originally Posted by dneal View Post

A saddle works as a lever, with the strings applying torque to the top. A taller saddle is a longer lever - giving more torque. There’s a limit to how much stress the saddle, bridge and top can handle; and 1/2” above the top seems to be the “ideal” height.
I don't understand how the saddle acts as a lever. Where is the pivot point designed to be? I always thought the bridge was designed to prevent the saddle from rotating, that torque on the saddle was a bad thing. Of course alot of things turn out to be not as I thought.
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Old 09-30-2018, 07:32 AM
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devellis devellis is offline
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Calling Alan Carruth! Calling Alan Carruth!
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Old 09-30-2018, 07:35 AM
dneal dneal is offline
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Quote:
Originally Posted by cuthbert View Post
If the...
We’re talking about flat top guitars, not violins.
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Old 09-30-2018, 07:38 AM
dneal dneal is offline
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Quote:
Originally Posted by pszy22 View Post
I don't understand how the saddle acts as a lever. Where is the pivot point designed to be? I always thought the bridge was designed to prevent the saddle from rotating, that torque on the saddle was a bad thing. Of course alot of things turn out to be not as I thought.
The pivot point is at the base of the saddle. The bridge does prevent the saddle from rotating, and that’s why torque is applied to the top.
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Old 09-30-2018, 07:39 AM
dneal dneal is offline
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Quote:
Originally Posted by devellis View Post
Calling Alan Carruth! Calling Alan Carruth!
Seems that not enough people pay attention when he posts...

—edit—

Quote:
Originally Posted by Alan Carruth
Changes in string height off the top can alter the tone, but if you keep things in a 'normal' range you might not notice much change. Note that it's the string height off the top that makes the difference in tone, not the change in break angle.
Quote:
Originally Posted by Alan Carruth
Bridge rotation distorts the top, and this alters local stiffness, which, in turn, changes the way the top vibrates. Obviously the higher the strings are off the top the greater the effect. In my experiment raising the strings from 11mm off the top to 18mm nearly doubled the rotation of the bridge: pretty much the expected linear change, and this altered the way the top vibrated.Changing the break angle without changing the height also changed the way the top vibrated, but only a very little bit, and far less than changing the height. More to the point, it made no measurable or audible change in the way the guitar worked. I included it in my earlier post more for completeness than anything else. Could it change the tone, in theory? Of course; anything can. Does it in practice? Not that I can tell.
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Originally Posted by Alan Carruth View Post
I did a rather thorough experiment on the effects of break angle and string height off the top some time ago. People often change the break angle by putting in a taller saddle, and report that the guitar sounds better. I worked out a way to isolate the two variables of break angle and height off the top, and made careful measurements of the sound output of the guitar under identical plucks, and also listening tests to see whether people could hear the difference. The results were pretty clear.

In the listening tests, when I had people compare the sound when the break angle was different but the string height off the top was the same they were guessing, saying it was 'the same' about half the time and 'different' the other half. This was true across the board; no individual got it right significantly more often. When they listened to the sound when the string height was different, but the break angle was the same, almost everybody heard the change.

Measurements showed that there was no significant difference in the sound the guitar produced when the break angle was altered. When the strings were raised further off the top there was a bit more energy in the signal at two frequencies.

One was the second partial of the string. This is due to the fact that the string gets tighter twice for every full cycle of vibration, and pulls the top of the bridge toward the nut. This 'rocking' motion of the bridge doesn't produce much sound, for a number of reasons, and didn't add to the power of the instrument as far as I could tell with the measurements I could make. However, it does change the timbre somewhat...

...Making the break angle higher does have one effect for sure: it increases the tipping force on the saddle. This tends to deform the slot and, in extreme cases, can break out the front of the bridge. Structurally there's every reason to keep the break angle as low as you can. Acoustically, so long as the string stays in contact with the saddle top through it's whole vibration cycle, and doesn't roll from side to side, it will transmit all of the of the signal to the saddle. What the saddle and bridge do with it after that is their business....
This probably doesn't require more than about a 15 degree break angle, which is what you get on most guitars over the nut.
Quote:
Originally Posted by Alan Carruth
...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...
Quote:
Originally Posted by Alan Carruth View Post
One of the experiments I have done was a look at the relative effects of string height and break angle on the sound. People post saying that they increased the break angle on their guitar and got 'better tone'. When I would ask how they got the higher break angle, a lot of the time it was from putting in a taller saddle. This changes both the break angle and the height of the strings off the top. I wanted to isolate the variables.

I have described this experiment a number of times on various sites on line, so I won't go into details at the moment. I'll say that I used the same guitar and the same set of strings throughout: the only 'playing' it got was from the test. That consisted of using a mechanical plucker that would impart the same (within +/- 2%) force to displace the string before releasing it, in a known spot along the string length, and causing the string to vibrate 'vertically' with respect to the plane of the soundboard. The tests were done in my 'semi-anechoic closet', which is far from perfect, but is, at least, quite reproducible. The plucks were triggered remotely, and the sound was recorded on my computer using a dB meter as a microphone, always in the same location. I made the bridge to allow for three different setup cases"
'A', where the strings were 11mm off the soundboard, and the break angle was 25 degrees,
'B', where the string height was the same but the break was 6 degrees, and
'C', where the string height was raised to 18mm off the top (don't try this at home!), and the break was back to 25 degrees.

I recorded six plucks of each open string for each case. A short initial segment of individual pluck sound was chosen from each string and case at random and strung together to produce a 'synthetic strum'. This was played back through earphones in random pairs to listeners who were asked if the strums were 'the same' or 'different'. I also evaluated the individual plucks for each string and across cases for:
1) 'rise' and 'fall' time,
2) peak amplitude, and
3) harmonic content.
Together rise and fall time and peak amplitude define the overall power in the pluck (there is no 'sustain' like you can have on a violin: no time after the initial rise when the power is not falling, so rise and fall times get it all). Harmonic content speaks to timbre.

What I found in the listening tests was the nobody could reliably distinguish the difference when the string height was the same and the break angle was changed. However, virtually everybody could pick up the change almost every time when the string height varied.

Basically, when the string height is increased the twice-per-cycle tension change has more leverage to torque the bridge and produces more sound. This puts more of the second partial, and sometimes more of the fourth partial, into the sound. There is also more power at the high-frequency 'compression wave' or 'zip tone' pitch,since that also acts by pulling the bridge forward. However, the overall power output does not increase when the string height does: there is a noticeable change in timbre, but not a change in power.

Thus it appears that there is no playoff for increasing the break angle beyond
the minimum that is required to keep the string in contact throughout it's vibration cycle. This makes sense, since the forces the string exerts on the saddle top as it vibrates are fixed, and readily definable: increasing the break angle does not 'put more power into the top', since that's limited and all the force is transmitted so long as the string remains in contact. I will note that the low break angle I used would not be sufficient for normal playing, where there is some sideways force on the string end that could 'roll' it sideways across the saddle top. I strongly suspect that a break angle beyond 15 degrees or so is unnecessary, but can't demonstrate it with my data.

Increasing the break angle has costs. If you do a vector analysis on the bridge loads you'll see that the actual force the string puts on the saddle top bisects the break angle. This can be resolved into two components: a 'downward' force against the bottom of the saddle slot, and a 'forward' force that is trying to tip the saddle toward the nut. The greater the break angle the more tipping force you have. At a 45 degree break the tipping force is equal to the down force, and about 70% as great as the string tension, if I've got the math right. This is trying to break out the front of the saddle slot, and sometimes succeeds. With more break angle the tipping force only gets larger. This can be mitigated by routing the saddle slot at a backward angle. When the saddle angle bisects the break angle there is no net tipping force. That's how violins get away with that tall, skinny bridge that just sits on the top.

At some point I want to do a similar experiment on saddle material. I think it plausible that the material could change the sound, probably by acting as a filter, but it would take some effort to get all the data. I did one preliminary experiment and could not measure any difference, but that was not as carefully done as the work cited above.

Last edited by dneal; 09-30-2018 at 08:06 AM.
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Old 09-30-2018, 07:44 AM
ripdotcom ripdotcom is offline
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I think there is some confusion as to pitch angle and height in this thread. The OP wants to know about height. Some individuals will lower a saddle and find an excellent playability combination of neck relief. Some people will utilize the truss rod first to lower the action. Some people dont understand this and automatically think a low saddle needs a neck reset when the guitar could be adjusted differently and maintain a higher saddle. I have an 00-18V with a very low saddle however i could easily put a taller one in it and adjust the action accordingly with the truss rod but it plays so excellent now I wont bother. Now the pitch is a different story and thats probably why there is a picture of a violin here. There is a break point in pitch angleand of course a taller saddle will allow fo rmore of a pitch but I dont know how much more it matters after 15-20 degrees if any. Then again yo ucan ramp a low saddle and achieve more even on a lower bridge. I have some at a 45% angle on some but I doubt its much different ton than if it was at 20 degrees. Just make sure there is some pitch or its like a telecaster B and E without string retainers.
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Old 09-30-2018, 08:10 AM
AcousticDreams AcousticDreams is offline
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Quote:
Originally Posted by capefisherman View Post
Does a low saddle transmit the string vibration to the bridge and the top less efficiently than a tall saddle?
Depending on the guitar builders relative bridge and pin design, in most cases yes.
And in most cases, saddle height will also effect the break angle to the pin. Low break angle might give you more sustain and less attack. And High break angle gives you more attack and slightly less sustain.
However there are also other ways to increase break angle over the saddle without increasing saddle height. You can ramp the string groove on the bridge so that it is closer to the saddle. This will increase the break angle. Some say that this will increase the attack time and make that string more pronounced. In my own personal experiments for my guitars I have found this to be true. But again, this does depend on the builders design.
There is no right or wrong. Some people like the effects of a low saddle and break angle. Personally I like a little bit of height and greater break angle.
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