Silly question? Luthiers?

[Sweb]

The idea of maximizing string vibration through to the soundboard seems to be the ultimate goal where acoustics are concerned. What if the bridge plate was made of bone? Wouldn't this be a better material to use considering the string ball end is seated against it?

[kwakatak]

That'd be a pretty big piece of bone, wouldn't it. I'd figure they'd have to use a portion of cow pelvis or something...?

Seriously though, I don't know if "harder" is better. From what I hear, when Martin started using rosewood for their bridge plates there was some issues with the effect on tone.

[Sweb]

Originally posted by kwakatak That'd be a pretty big piece of bone, wouldn't it. I'd figure they'd have to use a portion of cow pelvis or something...? Seriously though, I don't know if "harder" is better. From what I hear, when Martin started using rosewood for their bridge plates there was some issues with the effect on tone.

No. It needn't be that big at all. It's actually about the same size, or smaller, than the bridge itself. And, the whole purpose of the harder material saddles (bone) and brass bridge pins is because they transfer vibration better than a softer material, which has more absorption, or attenuation.

The way I see it, vibration resides in the string all the way through to the ball end. With the better vibration transfering material in contact with the string and the soundboard both above and below, it seems to me that all has been done at that point to use the available vibration to its greatest potential.

[MyM.O.]

There is a guitar being made with a bone saddle. I just saw it on one of the forums. I forgot what it was though (sorry, old age ). I'll post the pic if I see it again.

[bjorn-fjord]

A factor you're not considering is the weight of the bridge plate. Ideally a soundboard will be as light as possible while maintaining enough rigidity to resist distorting under the tension of the strings.
The hardness of the bridge plate material really only addresses the issue of protecting soundboard from damage by the ball ends of the strings.
For acoustic considerations, stiffness is the key, not hardness. Ahem...

[Frets99]

Originally posted by kwakatak Seriously though, I don't know if "harder" is better.

But that's what she keeps telling me!!!

[Sweb]

Originally posted by bjorn-fjord A factor you're not considering is the weight of the bridge plate. Ideally a soundboard will be as light as possible while maintaining enough rigidity to resist distorting under the tension of the strings. The hardness of the bridge plate material really only addresses the issue of protecting soundboard from damage by the ball ends of the strings. For acoustic considerations, stiffness is the key, not hardness. Ahem...

 

 

Okay then. So a bone saddle imparts vibration in what manner, considering it is slected as THE material for inducing vibration into the sound board?

 

Another set of physics I've been considering lies in the grain pattern of the soundboard itself. It is uni-directional and therefore has a steering effect on vibration. Consider the practice of reducing the cross section of saddles adjacent to each string. The conventionally purported reason is to drive (steer) vibration in a more linear direction into the soundboard. This same physics consideration lies within the soundboard's grain in that the lion's share of the vibration is driven in a path no larger (wider) than the saddle itself and runs longitudinally between the soundhole and aft end of the top.

 

The bridge on my Larrivee OO-05 lies further away from the sound hole than on my OMV-09E. The OO-05 is louder and has better individual string response/projection than the OM. Is this because there is more material to "sing" between the bridge and soundhole? There has to be a rationale because the top on the OM is significantly larger yet it is the quieter guitar. The point I'm trying to highlight is that I think sound across the top is more uni-directional than omni-directional with losses incurred by perhaps to much attenuating material adjacent to the vibration path.

 

Now, back to the movie.

[bjorn-fjord]

Well I'm not physicist but I'll try to answer your questions from the perspective of my personal experience as a luthier.

Bone was chosen for saddles because it is quite hard and relatively light. The saddle needs to be hard because it is in direct contact with the strings. No other part of the soundbox is subjected to the same conditions to which the saddle is subjected.

I do not believe that the sound produced by the vibration of the strings transfering their energy to the sounboard via the bridge and saddle is "unidirectional". To be perfectly honest I don't even really know what you mean by that. Do you mean that the energy travels down the grain more efficiently than across the grain?

I can't say whether this is true or not. I do know that the grain is oriented the way that it is primarily for strength. The vertical and longditudinal grain orientation is the best configuration for resisting the pull of the strings. If you were to construct a soundboard in any other manner it would need to be much thicker to resist distorting under the stress.

OK, I read your post for the 3rd time and I think I have a better understanding of what you are getting at.

Are you saying that a narrower soundboard should sound better than a wider one because there is less superfluous material that needs to be driven? What about the dampening effect of the sides? The narrower the guitar, the closer the bridge is to the sides of the guitar.

IN GENERAL smaller bodied guitars are more responsive than larger guitars but they tend not to perform as well in the lower frequencies. Small bodied guitars respond as well as they do for a couple of reasons. For one, there is less mass to move. Secondly, guitars joined to the body at the 12th fret have more space between the bridge and the crossing point of the X-brace. This smaller size unfortunately compromises bass response. Bass is all about moving a lot of air. Smaller guitars just do not do this very well. The bass notes of a small guitar may sound good but it will lack the sonorous quality of larger guitars. Smaller guitars also likely won't sustain lower frequency notes as well as their larger counterparts.

Compare the bass response of your two guitars by playing a note at say the 9th fret on the low E string. The OM should outperform the OO in this particular comparison. Also consider that because the OM has a more massive top, it really should get heavier gauge strings than the OO for a fair comparison. Of course it's also possible that you got a really sweet OO and just a so-so OM.

[Sweb]

Yes, you pretty much have what I was getting at understood. I understand the physical properties of quarter-sawn wood as the proper cut for use in soundboards, or any other structure requiring the best available strength-per-weight ratios. We use it cut that way in making wooden wing spars, which it the main load/stress bearing component in a cantilever wing, for airplanes. Spruce is also the chosen material for airplane structures.

Yes, the OM does have better base sound. It isn't louder. It just sounds better. I also understand the hardness of bone saddles are such that they are, in my impression of your reasoning, a component of the guitar that serves both as a load bearer and vibration inducer. It is the latter that I explore with regard to the bridge plate. String vibration at work on the ball end of the string it is of little real use if not allowed to disperse. Instead, it is locally attenuated by the soft material normally used for these members. Vibrations, being similar to electrical current or fluids in motion - including gasses - tend to follow the path of least resistance. In this regard they will follow the grain as a natural conductor. The harder materials within the wood, running grain-wise, will tend to steer the vibration not unlike a toy slot car steered by a groove in the track it runs across. There will be cross-grain boundery excursions but most of the vibration will be channeled grain-wise.

If the OO-05 had a size similar to the OM I believe it would have the best of the OO's projection and OM's tone. I also think a bridgeplate of bone properties would serve as an enhancement to available string vibration. Think about it. The saddle rests in a slot in the bridge which separates the vibration from the top. It is the middleman. Eliminate the bridge (middleman) and directly induce the top. That's the purpose of a bone bridge, right? Only, in my example everything remains the same except the bridgeplate material.

You are the luthier. You know what you know largely based upon your experiences as learned from those who have gone before you. We can all describe ourselves that way. If you have the time and inclination, do a one-off outside that box just for exploration's sake. Anyone can do copy work, right?

[Tony Burns]

What about Ivory ( fossil that is ) ?

[Andrewrg]

Sweb, dude, you`re thinking too much-trying to analyse what makes a guitar sound good is like herding cats and only encourages nosebleeds!
I recommend a good dose of a great sounding guitar and a couple of beers.

[Blackwatch]

The reason you don't see alot of them is they look like this:

[bjorn-fjord]

Sweb,

If hardness of the bridge plate material is desirable, why not make it out of steel? Answer: Because it's too heavy and would restrict the movement of the soundboard.

I don't know if the hardness of bone would improve the energy transfer more than the additional weight would impede it.

I can't back this up with any measurable data, but I really don't think that bridge plates have a significant dampening effect on sound because I don't believe the ball ends resting on the plate really contribute much of anything. I've unstrung (destrung?) a guitar to find that one of the ball ends was not in contact with the bridge plate at all and I wasn't able to notice any impact on the sound. I like to think I have a pretty good ear.

[Cldplytkmn]

Originally posted by Blackwatch The reason you don't see alot of them is they look like this:

valiant effort... but no dice, clive... he's talking about the bridge plate inside the guitar.

[Sweb]

Originally posted by bjorn-fjord Sweb, If hardness of the bridge plate material is desirable, why not make it out of steel? Answer: Because it's too heavy and would restrict the movement of the soundboard. I don't know if the hardness of bone would improve the energy transfer more than the additional weight would impede it. I can't back this up with any measurable data, but I really don't think that bridge plates have a significant dampening effect on sound because I don't believe the ball ends resting on the plate really contribute much of anything. I've unstrung (destrung?) a guitar to find that one of the ball ends was not in contact with the bridge plate at all and I wasn't able to notice any impact on the sound. I like to think I have a pretty good ear.

 

 

Precisely. The ball end simply will not "ring" its power in the conventionally built guitar any more so than your example of being lodged away from the bridge plate in thin air. In other words, good ear or not, the ball end's potential is not realized at all so there is nothing to hear with a properly seated string or not. That's the whole point. A material need not have a molecular weight bordering on depleted plutonium. It merely has to be dense, as in bone, to act as a conduit.

 

Experiment: Removed the saddle and insert a piece of wood in its place. Simply stated, yes, but for argument's sake use a little imagination. Listen to the difference in the sounds of the string with a bone and then wood saddle. Now, slide a washer with a center hole smaller in I.D. than the string ball end O.D. From the inside of the guitar, slide the string through its respective hole. No bridge pin is necessary as the washer will now seat and retain the string against the bridge plate. Finish stringing the string the usual way. Now the ball end has a larger and more vibration sensitive inducer between it and the bridge plate. Using the wood saddle, what is the difference between the string's sound with and without the washer? The wood saddle is a tool in this example to remove the normal path of vibration as much as possible to find out how much can be heard from the ball end of the string. Remember, the string's vibration is not isolated to two points - nut and bridge - it dwells in the string and, from both terminations, completes a vibration path, or closed loop, through the neck and soundboard.

 

Your point about bass moving air is true, but only after the string's power has been absorbed by the soundboard. We are hearing frequencies - middle C at 440 Hertz, etc - and amplified by the absorption and release of these vibrations, or yield, from the soundboard in tones (not pitch) colored by the selected hardwoods adjacent to the soundboard and bulk/arrangement of other structural members. It is the absorption, or inducing into the soundboard, that is vital to the yield. Tap lightly, hear little. Tap hard, hear more.

[Blackwatch]

My bad .........Sorry....

[Cldplytkmn]

Originally posted by Blackwatch My bad .........Sorry....

 

 

no worries man... i actually had the same thought when i first skimmed the post...

[Andrewrg]

Sweb, when it comes to theory and practise when addressing the acoustic properties of a guitar we come up against an insurmountable obstacle-inconsistency of materials.
Two identical guitars, adjacent on the production line are very likely to sound quite different from one another.
Therefore if we are to have any meaningful result from such an investigation as you propose the one single most important thing we are lacking is a control.
Take an example. My friend and I both own same year Martin D28`s. Both are made from the same woods, both are strung the same, have identical nuts, saddles and bridge pins. Both sound very different.
So, yes, any change you make to a guitar will affect everything else but not in any consistent way, guitar to guitar.
So, given the aforementioned inconsistencies the bridge plate material MAY make a difference in tone in one guitar but not necessarilly the other in an audibly measurable way.
Therefore we could not categorically say it was the bridge plate which made a difference.
Also it would be impossible to eliminate all the variables other than the plate in order to determine the cause of change, the guitars tone being the result of the sum of its parts.
Dont know if I`m making any sense here, I aint a scientist!

[bjorn-fjord]

Damn you Sweb, you're making me think!

More thoughts...

Is it not possible that if the bridge plate material is too hard it will actually resist transmitting the strings' energy to the soundboard?
You spoke of the energy "loop" produced by the string and fed through the bone and wood and then back to the string.
This is grossly oversimplified but if the bridge plate material were titanium isn't it likely that the energy from a plucked string would just bounce right back into the string and not into the surrounding wood?
Imagine driving a car into a strongly fortified brick house. The energy from the car's momentum would bounce right off the bricks and back to the car, destroying it. But if you drove a car into a wood house, much more of the energy would be transfered to the house, inflicting greater damage to the structure.

Would this analogy not also apply to the subject at hand?
If so, a guitar's bridge plate should be made of the weakest, lightest material possible that is still stiff enough to resist the twisting forces from the bridge and hard enough to resist damage from the ball ends.

Notice that the brigde plate on a classical guitar is spruce. Also there is a builder (some Japanese guy in California) of beautiful steel strings who makes his bridge plates from a composite of rosewood and spruce.

[Sweb]

Originally posted by Andrewrg Sweb, when it comes to theory and practise when addressing the acoustic properties of a guitar we come up against an insurmountable obstacle-inconsistency of materials. Two identical guitars, adjacent on the production line are very likely to sound quite different from one another. Therefore if we are to have any meaningful result from such an investigation as you propose the one single most important thing we are lacking is a control. Take an example. My friend and I both own same year Martin D28`s. Both are made from the same woods, both are strung the same, have identical nuts, saddles and bridge pins. Both sound very different. So, yes, any change you make to a guitar will affect everything else but not in any consistent way, guitar to guitar. So, given the aforementioned inconsistencies the bridge plate material MAY make a difference in tone in one guitar but not necessarilly the other in an audibly measurable way. Therefore we could not categorically say it was the bridge plate which made a difference. Also it would be impossible to eliminate all the variables other than the plate in order to determine the cause of change, the guitars tone being the result of the sum of its parts. Dont know if I`m making any sense here, I aint a scientist!

 

 

Yep, yep and yep. No 2 soundboards are alike. The variances in the tonewoods may also flavor it differently as well as the bracing and the bridge and et al, ad nauseum.

 

So, what you describe is the norm. I'm describing something else, though quite possibly of little sonic consequence, to eek out an enhancement that may be lurking untapped. That's all.

[Sweb]

Originally posted by bjorn-fjord Damn you Sweb, you're making me think! More thoughts... Is it not possible that if the bridge plate material is too hard it will actually resist transmitting the strings' energy to the soundboard? You spoke of the energy "loop" produced by the string and fed through the bone and wood and then back to the string. This is grossly oversimplified but if the bridge plate material were titanium isn't it likely that the energy from a plucked string would just bounce right back into the string and not into the surrounding wood? Imagine driving a car into a strongly fortified brick house. The energy from the car's momentum would bounce right off the bricks and back to the car, destroying it. But if you drove a car into a wood house, much more of the energy would be transfered to the house, inflicting greater damage to the structure. Would this analogy not also apply to the subject at hand? If so, a guitar's bridge plate should be made of the weakest, lightest material possible that is still stiff enough to resist the twisting forces from the bridge and hard enough to resist damage from the ball ends. Notice that the brigde plate on a classical guitar is spruce. Also there is a builder (some Japanese guy in California) of beautiful steel strings who makes his bridge plates from a composite of rosewood and spruce.

Take a tuning fork, strike it one good time and place the handle end directly on one of your front teeth. Then, after you've come to your senses, do it again but have an isolator - piece of wood flat stock superglued to the bottom of the handle - and observe the difference.

Soft material attenuates. Hard material essentially becomes integral, or one with the vibration source and rings-through as if it were the string.

Edit: In this example your tooth is the bridge plate.

[smokiee]

titanium alloy... somebody make one!!

adamantium.. well... if wolverine wouldn't mind hahaa

diamonds.... wonder how that'd sound

reinforced carbon fibre.... it could work

[bjorn-fjord]

Originally posted by Sweb Take a tuning fork, strike it one good time and place the handle end directly on one of your front teeth. Then, after you've come to your senses, do it again but have an isolator - piece of wood flat stock superglued to the bottom of the handle - and observe the difference. Soft material attenuates. Hard material essentially becomes integral, or one with the vibration source and rings-through as if it were the string. Edit: In this example your tooth is the bridge plate.

 

 

I'm aware of the dampening characteristic of softer materials but I don't think your illustration is really addressing the point. Since we already agreed that the ball ends resting on the bridge plate are not really a significant factor in transmitting the energy from the strings to the soundboard, my tooth, in your example would be the saddle, not the bridge plate. In fact the bridge plate is pretty far down in the succession of material that the sound energy must travel through, ie, saddle, bridge, and soundboard.

 

My point is that it wouldn't matter what material you placed 3 layers behind my tooth, the effect would be the same.

[Sweb]

I used to think the strength of a signal, in this case vibration, was a contained phenomenom existing between two tap points touching the string. In this case the saddle and nut. But that isn't completely true. While it is true that these points, especially the load bearing point across the saddle, will absorb the greatest energy of the signal, that doesn't mean the signal ceases to travel in the string beyond the saddle. It continues on. The highest energy potential travels through the saddle, bridge and is induced into the sound board. The remaining energy travels through the string to the ball end. It remain there until completely dampened. It is this residual energy that I'm wondering about and if it is significant enough to give additional boost to the sound board through the right conductor rather than be attenuated by the wood.

Let me qualify this thinking another way. I had a bridge doctor device installed in a 12 string guitar. Due to the manner in which the strings were retained one of the hi E strings did not touch the saddle. This was not intentional. The ball end passed through a brass fastener that protruded above the bridge placing the string at a higher elevation from the bridge than normal. As the saddle was radiused to the fretboard while the bridge was not, the string missed the saddle. Sonically, it sounded identical to its counterpart hi E. This brass fastener passed through the bridge and was retained against the bridge plate with a washer and nut.
The resulting intonation characteristics of that string were off-kilter but that was the only loss by contrast. The tension on the string was a straight pull - no perpendicular load to the soundboard - so it stands to reason the resulting torque load on the brass fastener was fairly equal above and below the soundboard rather than through the normal downward load exerted on the saddle via the break angle. And, there was more material above the soundboard than below due to the dimensions of the bridge and bridgeplate, respectively. No saddle contact, no break angle yet little effect on the signal by contrast.

It's a theory of sorts. If the facts don't support it, it's faulty. An experiment would eek out the facts.