What if an acoustic guitar did not need top bracing?

[drguitar001]

I ask this question because I recently have been working on different bridge designs, seeing as the current wood bridge glued to the top with bridge plate below and various top bracing for strength and stability has been around for a long time without much improvement. Certainly, if it ain't broke, don't fix it. However, they do break, with some regularity . And the stresses caused by the pull of the strings and the twisting of the pin bridge can cause all sorts of havoc on the top of the guitar (pulled bridges, twisted/sunken tops, cracked bridges, broken braces...etc).

So I just came up with a acoustic bridge design that has zero twist and nearly zero pull or push on the top. The string energy is transferred to the top by the typical "gluing of the bridge", but there is no other stress other than the string energy. The bridge essentially "floats" without any downward or upward pressure on the top and no torque (twisting). The new design bridge is similar to the mass, shape and size of the typical bridge.

So the question is, would there be any advantage for guitar makers to be able to design the top of a guitar without needing to consider 160+pounds of pull and twist in the bridge area? Could the guitar actually be much lighter braced with only considerations of tone as the concept for bracing? Could the guitar be made louder without the heavy bracing (in other words, would the energy of the strings work to produce a louder tone without having to be "controlled" by heavy bracing to keep the top from imploding?

[kydave]

So how do the strings attach to impart no pull?

Like the old floating Stella bridges?

[warfrat73]

Explain, then, how energy is transmitted to the top/soundbox to be amplified.

A joke, or a way to circumvent the laws of physics?

[Rodger Knox]

Originally Posted by kydave

So how do the strings attach to impart no pull?

Like the old floating Stella bridges?

Looks like that one floated a bit south...

I'd like to see a NEW bridge design that has zero twist and nearly zero pull or push on the top.

The problem is that the twist, pull, and push of the strings on the bridge is what makes a guitar sound like a guitar.

[Earl49]

What Rodger said.....

A bridge that does not pull the top in shear or apply torque is usually called an archtop with a tail piece for string attachment and a floating bridge. Archtops sound different, because it is a different mechanism imparting the vibration to the top. There is only down pressure on the bridge. Are you perhaps talking about something like the JLD Bridge Doctor?

My Rainsong carbon fiber guitar does not have - or need - any top bracing. The CF top is much stronger than lightweight tone woods like spruce or cedar.

[drive-south]

Make the top 1/2" thick and you won't need braces.

[RustyAxe]

It seems to me that regardless of how you attach the strings, there would still be considerable pull longitudinally ... the strings pulling from the neck to their attachment points.

[Bax Burgess]

Maybe a Batson or Babicz meets those requirements.

[slimey]

most cf guitars have no braces on the top.

[tak2]

You might look at the Boulder Creek Guitar website if you are interested in an alternative support and bracing system.

[drguitar001]

Actually. the Stella is not far from what I designed. The big difference is that the Stella has a bridge/saddle that is pressed down to the top from the tension of the strings, pulling down across the bridge/saddle from the tailpiece. My design is different in that there is a tailpiece but the tailpiece is only for holding the strings under tension (sending the pull of the strings to the end of the guitar (end block). And here is what makes my bridge/saddle design different, the tension of the strings across the bridge/saddle does not hold the bridge in place, nor is it the way the energy of the strings is transferred to the top. In my design, there is direct energy transference from the string to the top, there is a 45 degree break angle behind the saddle that solidly connects the string to the saddle, yet there is no deformation of the top from either pull tension of the strings nor from torquing (or twisting) of the bridge on the top. The top of the guitar would not suffer from deformation of string tension or pressure, but would have a solid connection to the energy from the strings when plucked. This would effectively allow the top to be made a thin or lightly braced as the builder would like without any concern for "imploding". In addition, with the removal of torquing the top and the top being under constant tension, less energy would be lost to deformation and top tension (possibly more sustain and greater volume?).

I'm toying with building this bridge and gluing it to one of my less expensive guitars to see how well it works. The problem being that it would make sense to remove (or at least thin down considerably) some bracing to make full use of the radical bridge/saddle design.

Any builders out there that would like me to build a prototype bridge for them to try?

[drguitar001]

Originally Posted by warfrat73

Explain, then, how energy is transmitted to the top/soundbox to be amplified.

A joke, or a way to circumvent the laws of physics?

Without actually drawing it out for you, I will explain. The bridge is glued to the top just like an average D18. However, a tailpiece is added to take the load of the lateral pull of the strings (~160+ pounds of tension). In this way, the tension and torque is removed from the bridge as are the hold in the top needed for pins and such.

By itself, that bridge system would sound terrible with no real connection of the strings to the top. My bridge/saddle design actually fixes this by creating a very tight connection between the strings and the saddle on the bridge, without pulling up or pushing down or twisting the bridge itself. With a solid connection between the string and the top and no tension, all the energy from the string is available to vibrate the top of the guitar without restriction of any kind.

[drguitar001]

Originally Posted by Earl49

What Rodger said.....

A bridge that does not pull the top in shear or apply torque is usually called an archtop with a tail piece for string attachment and a floating bridge. Archtops sound different, because it is a different mechanism imparting the vibration to the top. There is only down pressure on the bridge. Are you perhaps talking about something like the JLD Bridge Doctor?

My Rainsong carbon fiber guitar does not have - or need - any top bracing. The CF top is much stronger than lightweight tone woods like spruce or cedar.

No, my design does not need any type of additional bracing and looks very much like a standard bridge. It is completely different from an archtop "floating" bridge in that the bridge does not rely on the string tension to push the saddle/bridge against the top to transfer energy. The bridge is glued like a normal bridge, but does not have any (or very little) tension on it. This allows the bridge to transfer all string energy to the top unimpeded.

[drguitar001]

Originally Posted by Bax Burgess

Maybe a Batson or Babicz meets those requirements.

The Batson is an interesting design and similar in concept but a different design to what I came up with. However, their bridge still applies torque to the top (mine does not) but the idea of transferring the tension of the strings to the end of the guitar is similar. Batson also does lots of interesting guitar modifications. My bridge is a simple modification that does not need any other modifications to work. However, their bridge design is close enough for me to hear that such a similar design will increase sustain and fullness of tone. I have to wonder what might happen if internal bracing could be lightened enough to really allow the top to sing without restriction?

[AZLiberty]

Originally Posted by drive-south

Make the top 1/2" thick and you won't need braces.

My Rainsongs are unbraced, and the top is considerably thinner than that.