What if an acoustic guitar did not need top bracing?

[gitarro]

Wouldn't such a bridge move that one towards the direction of an archtop sound? It may be that a flat top needs the torque effect to at least some degree to produce it's characteristic sound...

[printer2]

So put it on your regularly built guitar and see how it performs, what have you got to loose. Without a diagram I can't seem to visualize how your bridge works. But aside from my lack of visualization, there is not a lot of pressure on a top using a regular bridge and a tailpiece. With 160 lbs of pull I doubt there is more than 5-10 lbs pressure on the top.

[drguitar001]

Originally Posted by gitarro

Wouldn't such a bridge move that one towards the direction of an archtop sound? It may be that a flat top needs the torque effect to at least some degree to produce it's characteristic sound...

I wouldn't call myself a luthier even though I have designed and built a dozen or so instruments in my life. But I have repaired many hundreds of guitars and it's been my understanding that the primary cause for a guitar's tone (other than choice of woods, thickness of top, size/shape of body and about a dozen other things) is the type of bracing used on the soundboard.

Archtops are arched/carved to begin with and often have longitudinal braces running nearly the entire length of the top, while flattops often use an X brace with shorter tone bracing leading off the X. I don't believe that the tailpiece itself has much, if anything, to do with the actual tone of the instrument. However, having the pressure from the strings hold the bridge in place on an archtop probably causes some tonal differences compared to the glued bridge of the flattop.

[drguitar001]

Originally Posted by printer2

...With 160 lbs of pull I doubt there is more than 5-10 lbs pressure on the top.

However, there is 160+ pounds of torque on the top. In addition, there is also 160+ pounds of pull (laterally) on the top. Both of these stressors cause some level of deformation to the soundboard of the guitar.

Now if you are talking about an archtop guitar, I can be pretty sure that the floating bridge on these animals do have quite a bit more than 5-10 pounds of downward pressure on the top when tuned to pitch. However, archtop guitars are not under as much twist (torque) and really only need to be able to resist the downward pressure of the tuned strings.

In either case, there seems to be a stress on the top that could cause problems (not as much with the archtop unless the braces collapse).

[drguitar001]

A quick review of my posts will show that nowhere among them did I ever state that what I asked was unusual thinking nor did I state that everyone does something the same way. I am well aware of the myriad of bracing designs used by countless builders. Many of these builders are looking for a "Holy Grail" tone while dealing with the devastating torque and pull of strings. So your entire aggressive post is based on nothing and is entirely a figment of your angry imagination.

The original post and premise asked if the top of the guitar did not have 160 pounds of pull and torque applied to it, would it be advantageous tonally to the builder? My question is sincere as I am not sure it does help. I do know that various guitar types (archtops, modern flattops, classical, ladder braced flattops...etc.) get much of their tone from the choice of bracing used. So the question about "What if an acoustic guitar did not need top bracing" is a valid one since my bridge design would completely eliminate the concern about stress from torque and pull on the top allowing the builder to design bracing solely for tone and volume.

[printer2]

Originally Posted by drguitar001

However, there is 160+ pounds of torque on the top. In addition, there is also 160+ pounds of pull (laterally) on the top. Both of these stressors cause some level of deformation to the soundboard of the guitar.

Now if you are talking about an archtop guitar, I can be pretty sure that the floating bridge on these animals do have quite a bit more than 5-10 pounds of downward pressure on the top when tuned to pitch. However, archtop guitars are not under as much twist (torque) and really only need to be able to resist the downward pressure of the tuned strings.

In either case, there seems to be a stress on the top that could cause problems (not as much with the archtop unless the braces collapse).

How do you figure there is 160 lbs torque on the top? Almost all the force is in the same plane of the top. The force not parallel to the top is due to the height of the strings off the top. The angle is very shallow (as far as things go) so the force on the top is small. On a bridge and tailpiece guitar there is no torque on the top as the bridge is only producing a force straight down unlike a fixed bridge (no tailpiece). Maybe the language you are using does not quite convey what you intend to get across.

[The Bard Rocks]

DR, the only way to find out for sure is to do it. You've built a dozen, now it can be 13. First, I would take as virtually valueless beater and try it out and if that seemed to work, make one like you are talking about. You may have something - or not - and that will help answer the question.

Yes, I would think long about the longitudinal pull.

[Larry Pattis]

A properly-made double-top (nomex, etc.) guitar does not require bracing for strength/stiffness purposes.

Charles Fox builds his top-guitar in this fashion...no bracing.

[devellis]

Originally Posted by The Bard Rocks

DR, the only way to find out for sure is to do it. You've built a dozen, now it can be 13. First, I would take as virtually valueless beater and try it out and if that seemed to work, make one like you are talking about. You may have something - or not - and that will help answer the question.

Yes, I would think long about the longitudinal pull.

I think this sums it up. None of us can meaningfully comment on your concept without actually seeing and hearing a guitar that uses it.

If strings run over a bridge and saddle without down-force but, say, through a channel of some sort, then their vibrations could be transferred to the bridge and hence to the top. But the top would have to be incredibly light for those vibrations not to be completely dampened, it seems to me. It's kind of like pulling a bow string back a millimeter. The bow wouldn't be subjected to much pressure but neither would there be much energy in the string when it was released. Some banjo players use a very low bridge and a very high tailpiece setting so that the bridge only creates a very straight break angle from the tailpiece to the nut. But this requires a very thin, tight head on the banjo and a lot of energy input from the player to produce a loud tone. Is that the sort of arrangement you're referring to? The resultant tone, obviously, is nothing like a guitar's.

I may have this all wrong. We're all trying to guess what you're talking about. We can't meaningfully respond without at least seeing what you mean. Better still would be seeing and hearing a functioning guitar that uses the design. We will have difficulty accepting the idea that you've designed a better mousetrap (a bold claim that you're making at least implicitly) without some credible evidence. And vague verbal descriptions don't add up to much evidence, respectfully.

[drguitar001]

Originally Posted by The Bard Rocks

DR, the only way to find out for sure is to do it. You've built a dozen, now it can be 13. First, I would take as virtually valueless beater and try it out and if that seemed to work, make one like you are talking about. You may have something - or not - and that will help answer the question.

Yes, I would think long about the longitudinal pull.

I think you are right. I will find some time to build the bridge and install it on one of my acoustics. Even though I have it drawn out, you can never tell how it will work until it is in place on an instrument.

[drguitar001]

Originally Posted by Larry Pattis

A properly-made double-top (nomex, etc.) guitar does not require bracing for strength/stiffness purposes.

Charles Fox builds his top-guitar in this fashion...no bracing.

I've seen, but never played, one of these guitars. It was a while back, so I cannot comment on whether I like the tone or not. Carbon fiber tops also do not require bracing and tend to be pretty loud instruments. This is what had me wondering whether a solid wood top without bracing would also be louder than normal.

[drguitar001]

Originally Posted by devellis

I think this sums it up. None of us can meaningfully comment on your concept without actually seeing and hearing a guitar that uses it.

If strings run over a bridge and saddle without down-force but, say, through a channel of some sort, then their vibrations could be transferred to the bridge and hence to the top. But the top would have to be incredibly light for those vibrations not to be completely dampened, it seems to me. It's kind of like pulling a bow string back a millimeter. The bow wouldn't be subjected to much pressure but neither would there be much energy in the string when it was released...

I may have this all wrong. We're all trying to guess what you're talking about. We can't meaningfully respond without at least seeing what you mean. Better still would be seeing and hearing a functioning guitar that uses the design. We will have difficulty accepting the idea that you've designed a better mousetrap (a bold claim that you're making at least implicitly) without some credible evidence. And vague verbal descriptions don't add up to much evidence, respectfully.

Hmm... first off, I do not think of it as a "better mousetrap", more of an evolutionary step. You see, I was trying to design a flat top mandolin for my son that did not need the typical "bent wood top" seen in Martin mandolins to create sound transference between the strings and the top. Then I realized that to get the energy from the strings to transfer to the top, all you really need is to tightly clamp the strings to the bridge (like a pin bridge). But then the problem is that 8 strings pinned to the top of a mandolin is an awful lot of tension and torque on the top and could (would?) cause more problems than it might be worth (glue surface so large to possibly weigh down the top...etc). So then I wondered if I could design a bridge that uses a tailpiece but also clamps the strings tightly to the bridge so that picked energy is directly transferred to the top and not lost in some way to top compression or torquing. And that is when it came to me.

I would rather not post pictures of the design on a forum, even though it may only be evolutionary (certainly not revolutionary). However, if a luthier would like to try the bridge, I would be happy to show them the drawings and explain the parameters. In the meantime, I my try it out myself when I find a spare dozen hours or so.

[DenverSteve]

Originally Posted by printer2

So put it on your regularly built guitar and see how it performs, what have you got to loose (lose).

Originally Posted by The Bard Rocks

DR, the only way to find out for sure is to do it.

My thoughts as well. The next step in any idea development is a prototype. If it works, it should be at least as loud on a modified brace-topped guitar as the traditional bridge. Then maybe get a kit and build your guitar(s) with no top bracing/ or simply remove the bracing from a low-end solid-topped guitar and see what happens. You may have the next "got-to-have" product in the acoustic guitar world. Or, you may have a great 6-month hobby. Good luck.

[Jabberwocky]

Nik Forster has a nice solution:

[Jabberwocky]

Torres-La Leona-style Bridge.