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I prefer the tone from traditionally braced guitar tops that are under the full stress from string tension.

Currently I'm in a slow process of building a few new instruments using my system. Both will be OM profile bodies with 3.5 degree angled neck with a target saddle height of about 25-27mm. First instrument I plan to do a 2mm median soundboard thickness (maybe tapered to the edge) with very light lateral /parabolic bracing just to achieve more isotropic stiffness of the soundboard. They will feature composite force compensators aiming for lowest possible mass. I'll check back in when I have some results.

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Breanna Anderson
https://glyphstone.studio

Why such a tall saddle if you are not using it to produce a break over angle and down force on the top?

I am. The high bridge produces increased acoustic forces on the soundboard.

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Breanna Anderson
https://glyphstone.studio

glyphstone:
I found your answer a bit ambiguous. I asked:
"Why such a tall saddle if you are not using it to produce a break over angle and down force on the top?"

And you replied:
"I am".

Are you using the tall bridge to produce a downward break angle at the bridge? My impression was you were trying to eliminate those static forces.

You added:
"The high bridge produces increased acoustic forces on the soundboard."

In a post I made in this thread on Nov. 18 I mentioned an experiment I did on the effect of varying the string height off the top and the break angle on a standard Classical guitar. Basically: so long as the string remains in contact with the saddle top throughout it's entire vibration cycle all of the signal, the 'acoustic force', is transmitted to the top. The only function of the break angle is to keep the string from hopping off the saddle or rolling or sliding sideways.

In my experiment I used a mechanical 'plucker' to impart a known force at a given location in a vertical direction relative to the plane of the soundboard. In that case, with no sideways forces, six degrees of break angle worked fine. Increasing it to ~25 degrees made no audible or measurable difference. Raising the string height off the top increased the relative strength of the twice-per-cycle 'tension' signal (the second and fourth partials). It also increased the relative strength of the longitudinal 'zip' tone. However, neither of these increased the total output of the string, neither the amplitude nor the duration of the tone was changed. After all, the amount of energy being fed into the string was the same every time: an increase at one frequency seems to have been balanced by a small decrease everywhere else.

Break angle at the saddle doesn't need to be down or up. Pianos run the string over a saddle with a pin (or more than one) between it and the hitch pins. The string is bent slightly sideways to keep it in position, but there is a down force. Resophonic guitars often use a tight notch in the the saddle to capture the string so it won't move up and down.

I'm imagining a bridge set up so that it essentially 'floats' freely, with it's base exactly at the plane of the top. The bridge is then glued to the top to transmit the 'up and down' forces. Those are by far the strongest sound producers. Besides, if you've eliminated the 'torque' and 'transverse' forces on the saddle, what else is left?

You say you did your experiment on a "standard Classical guitar", so I assume the strings are tied off at the bridge. If that is the case then indeed the break angle simply has the function of keeping good contact between the string and saddle. In my design, the bridge is usually a floating bridge but the main point is that strings are terminated at the tailpiece so the downward force of the break angle is applied directly to the soundboard, it's not just a force triangle within the structure of the bridge/saddle construction itself. In my design, the increased static and acoustic transverse forces are applied to the top/soundboard but the complementary break angle of the cables and force compensators within the guitar cancel out the increased static transverse constant force of about 38 lbs force. The high break angle does provide for efficient transfer of acoustic transverse forces into the soundboard. The compliance (low spring factor) of the internal force compensators allow for good soundboard movement which is how I can achieve a very high monopole mobility.

_________________
Breanna Anderson
https://glyphstone.studio