Where Did Our Bridge Come From? Answering Your Questions about Our Bi-Level Bridge
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- Опубликовано: 26 июл 2024
- We get so many questions about our bridge, especially our direct-coupled bridge. This week we’re going to explain exactly, comprehensively, all Mr. Yairi’s thoughts about this amazing design.
2:55 Direct Coupled Bridge vs. Bi-Level Bridge
3:50 Bridge Pull
4:32 String Tension
5:00 Mr. Yairi’s Solution
Featured in this Episode:
Chris is playing the Alvarez Masterworks MDA66CESHB: alvarezguitars.com/guitar/mda....
Dee is playing the Yairi FYM60HD OM Guitar: alvarezguitars.com/guitar/fym....
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I would love to have the Alvarez designed bridges on all my guitars. I am absolutely convinced that both the bi level and direct coupled bridges are the best deigned bridges in the world. Thanks again Chris and Dee, for sharing your informative video's with us.👍👍🎸
It's certainly working for us! Glad to hear its working for you too @ronchave6354
There is still upward pressure at the bridge pin. However, it is spreading the force over a much greater area. The end result is no bridge lift and better top activation. Brilliant!
Great video. Very informative and thought provoking. Thanks!
2nd page of my Patent post: Description
BACKGROUND OF THE INVENTION
This invention relates to guitars having a resonance body or a sounding box such as a folk guitar and a classic guitar and other acoustic stringed instruments.
Unlike so-called "electric guitars" providing electrically synthesized sound, guitars having a resonance body are characterized in that they produce natural or acoustic timbre. The timbre depends greatly on wood materials of a surface plate, side plates and the like that constitute the resonance body. Therefore, vibration of strings must be transmitted reliably to the surface plate through a lower bridge, but in the conventional guitars of this kind, the lower bridge is merely bonded to the surface of the surface plate by an adhesive.
While the strings are stretched for a long period of time, bonding power drops and the lower bridge peels off from the surface plate. It also peels off from the surface plate due to the difference of their expansion coefficients, and the surface plate is curved by the tensile force of the strings. Unless the bond surface of the lower bridge is sufficiently great, therefore, it cannot withstand the tensile force of the strings.
SUMMARY OF THE INVENTION
It is therefore among the objects of the present invention to provide a bridge construction for acoustic-type stringed instruments which reliably transmits vibrations from the strings to the surface plate; to provide such a bridge construction that is secured to the surface plate and will not separate therefrom, and to provide such a bridge construction that does not deform the surface plate.
The bridge construction for an acoustic stringed instrument according to the present invention comprises an opening in the surface plate of the resonance body and a bridge member comprising a protrusive portion adapted to protrude into the opening in the surface plate, and a step portion surrounding at least a portion of the protrusive portion and adapted to engage the underside surface of the surface plate adjacent the opening. The construction includes means for mounting the strings on the protrusive portion of the bridge member in the direction of its width.
The bridge member is firmly fixed to the surface plate and reliably transmits the vibration of strings to the surface plate. The tensile force of the strings actually pulls the bridge member against the surface plate, and thus the bridge construction eliminates the problem of the bridge separating from the surface plate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the body of a folk guitar incorporating the bridge construction of the present invention;
FIG. 2 is a longitudinal cross-sectional view of the bridge construction taken along the plane of line 2--2 in FIG. 1; and
FIG. 3 is a transverse cross-sectional view of the bridge construction taken along the plane of line 3--3 in FIG. 1.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred embodiment dealing with a folk guitar, by way of example, will be described with reference to the accompanying drawings. In the drawings, reference numeral 1 represents a surface plate of a resonance body, 2 is its sound hole and 3 are strings. Reference numeral 4 represents a bridge member for fixing one of the ends of each string 3. The bridge member 4 is formed by cutting out a stiff wood material such as an ebony in such a fashion that it has a protrusive sectional shape. The bridge member 4 is then fitted into an elongate opening 5, bored in the surface plate 1 so as to extend in the transverse direction of the surface plate 1, so that only the narrow portion 4a of the bridge member 4 is exposed to the surface of the surface plate 1. Reference numeral 6 represents a backing plate which is bonded around the periphery of the elongate opening 5 on the back of the surface plate 1. A step portion 4b of the bridge member 4 is bonded to the periphery of the elongate opening 5 on the back of the surface plate 1 while sandwiching the backing plate 6 between them. Reference numeral 7 represents end pins that are fitted in holes in the protrusive section 4a in order to fix the strings to the bridge member 4. Reference numeral 8 represents a pillow, which is disposed movably on the surface plate 1 and separately from the bridge member 4 and has a curved plane shape. This pillow, too, is made of a stiff wood material such as an ebony, and a bridge 9 made of stick-like resin material is put transversely on the upper surface of the pillow 8. The strings 3 bridge over this bridge 9 and are spaced apart from the surface of the surface plate 1.
In the conventional folk guitars, the bridge is disposed integrally with the bridge member as is known in the art. Therefore, the bridge cannot move. In accordance with this embodiment, however, the pillow 8 is disposed separately from the bridge member 4 and the effective length of each string 3 can be adjusted as desired by a player by moving the pillow 8. Thus, delicate adjustment becomes possible. Furthermore, since the pillow 8 is disposed separately from the bridge member 4, it is possible to change the materials of the pillow and thereby change delicately the timbre inherent in the material employed.
As described above, in the acoustic stringed instrument in accordance with the present invention, the bridge member has a protrusive sectional shape and only its protrusive portion is fitted into the elongate opening 5 while its step portion 4b is bonded to the periphery of the elongate opening 5 on the back of the surface plate 1, thereby firmly integrating the bridge member to the surface plate. Therefore, the vibration of the strings is reliably transmitted to the surface plate 1, improving resonance. Moreover, the acoustic characteristics are improved. Deformation of the surface plate 1 and separation of the bridge from the surface plate due to the tensile force of the strings is eliminated.
Another great video gentlemen. Thanks for the info. I really do love my Alvarez masterworks. Saving up for the 2 piece.
Lovely video! Always been curious about the direct coupled bridge
Interesting
Thanks for all these discussions and your openness to pursue these topics
extremely fun series to watch and the instrumental at the beginning is my fav you played so far
Thanks so much for your willingness to talk about this. Very informative.
Chris. Would love to see an in-depth video of the Factory making the direct couple bridge. I think this would explain alot.
Thanks Anthony! Coming soon...
Great Video. Love the musical intro.
Love this channel! Not only are Alvarez guitar stellar instruments but their is real porpose in the effort to create the best ssound as wel as longevity. Keep up the amazing work.
Thank you Chuck, appreciate the kin d words :)
All non-classical acoustics have a bridge plate under the top to support the top when the strings try to pull up the bridge. I guess the separation of the pin section from the saddle section might increase the contact between the saddle and the soundboard, like an arch top has. Thanks for the explanation especially the diagram.
It does solve the bridge lifting issue, but the 2 opposing forces are still there. You could say that they may cancel each other out, but the down force on the bridge is more of a vector force imposed by the string tension and is probably less than the up force on the top since the strings are anchoring into the top, (this is also a vector force since the strings enter at about a 45 degree angle as opposed to being perpendicular to the top). The increased break angle of the strings, I would say, is putting more energy into vibrating the top than on a typical bridge design, so this should increase responsiveness and volume and have an affect on the tone. I'm sure there is an engineer out there that could do a force analysis if they are supplied with the string tension force and the dimensions of the bridge.
Thanks for the thoughtful comment Steve, certainly more investigation to do!
ENERGY created by the string in motion is the real issue, not the pulling / tension forces. What happens when the oscillation ENERGY - created by vibrating string - must be absorbed?
A) Using the DCB: String directly coupled onto the top transfers the entire oscillating string energy onto the top, and as a result, the entire top (having a much larger surface), absorbs oscillation energy more efficiently in ALL directions, from the pin across the guitar top. The received energy drops with the square of the radius of impact, and in this case, the radius of dissipation of energy from the pin is LARGER and more of the guitar top is excited.
B) Using the Bridge: String pinned to the bridge, transfers the energy onto the bridge. The bridge and the top are two independent oscillation energy consumers. Both must absorb the same amount of energy as the top alone in DCB design. Even a small loss lowers the amount of energy that can be transferred onto he guitar top. Let's presume that the bridge can transfer 90% of energy to the top, but it still retains 10% which it must use somehow. The bridge is made from a different material, glued on top, vibrates differently, and therefore uses the remaining energy to vibrate independently. Bridge, being independent, also vibrates left to right instead of top to bottom alone, so that tiny horizontal movement slowly DECOUPLES the bridge from the top. The energy that the guitar top received via the bridge is smaller in amount, and it must dissipate in a SHORTER radius of intensity from the pin on the bridge.
There is zero doubt that Direct Coupled Bridge transfers more oscillation energy right on the guitar top, and that energy excites the top in a wider radius until it's absorbed.
Another example we can use to illustrate this is to compare the guitar top and bridge as grounding/earthing devices for the electric energy from lighting. The bridge is too small to ground the entire energy of lightning, but the guitar top is a far more efficient grounding device.
Very informative guys. Mr. Yairi is an acoustic guitar genius!👍👍
We agree! Glad you enjoyed. 🙌
I have three Alvarez' hanging on the wall. They are amazing guitars and I play them more than my Martins and Taylor !
Thank you Thom, thats music to our ears 🎶
@@AlvarezGuitarsOfficial They really are the most amazing guitars on the market in their price range.
I think I have owned at least 7-8 over the years ! Never had a single issue with any of them !!!!
I have the wy1 cutaway rosewood cedar top .Awesome guitar
He did patent it. I’ve seen it somewhere. DCB is superior in my opinion. It feels and sounds different, and it just plain makes sense, when you examine it, as you have so clearly done here. Thanks for the video!
This is a engineering statics problem, not dynamics since nothing is moving, very straightforward, should get one of my old Ga Tech professors to make an analysis and use it in advertising (and compensate generously). Luthier Chris Alvarado at Driftwood Guitars talks about the string angle being as acute as possible and using solid pins to make the string contact as much as possible.
The genius of Mr. Yairi's guitar building lends itself to believing in his theories. I have two Yairi's; FYM66HDE and DYMR70. Both are superb guitars. The placement of the direct coupled pin set is different on each model, with there being more space in the dreadnought version. I am assuming this is intentional. Can you expound on the reason why? Or am I going off track?
Thanks MK, we'll make sure to include this in one of our Q&A videos!
Great video! I wonder if you could do a DCB version on the Alvarez by having a pin plate on the top instead of set in the top. Could still remove the opposing forces on the bridge, reduce bridge lift, and continue to allow for adequate production time in the factory line.
Interesting idea Steve!
ON the cusp of innovation, two questions: 1. Why did Alvarez make the MD Solid Wood series, in the mid 2000's, and then discontinue it, I own five models(MD70, MD90, MD 200C, MD 500 and yes, a 5000 Brazilian, two pattern's to die for)) and they are beyond the pale in sound et. al.
2. My luthier gave my newly purchased NOS 2007 European Model DY 40 DBKE a once over last year and said, "this type of design, with individual saddles and DCB; he did not know the design name, will eventually start to lift. He totally missed the engineering purpose of this innovative design. And the modern Yairi's have a separation space from the main bridge to the endpins and the Alvarez guitars are solid piece of wood with no space. And, yes, I can feel the difference of the DCB as it relates to my 1970's Yairi's/Alvarez's with regular "old school" bridges. Thanks for the reply.
In my thinking, the direct couple bridge would spread the pulling of the strings across the width of the top. As the Direct couple bridge is joined into the top. What do yous think Guys.
Are you familiar with the Babicz acoustic guitars? They also have a bridge separate from the pins, but they use an intermediate piece to hold the strings down on the bridge, ans they anchor the strings near the outer edge of the top. I'll admit, it's kind of odd looking, but I know a performer who has a couple of them, and he loves them.
Thanks Jim, we are familiar with the Babicz designs. It's great everyone has their preferred approach!
That means the top cant be lifted very much under string tension as the strings are anchored in a stronger area of the top. Its a bit like using a tail piece in effect but strings are still coupled to the sound board. Not the most aesthetic look but someone who has thought about the forces imposed on a guitar and how they may be overcome. He has the adjustable neck design as well.
D6 cort??? same
Since there is more upward pull on the back piece, is there a greater chance of getting a belly in the top behind the back piece?
Thanks for the question Rick. This is not something we experience with the DCB.
I thought that they used an oscilloscope back in the 80s to measure the increased resonance.
Wouldn't a tail piece like on a mandolin be the same type design but without the strings pulling up the sound board ? They've used them on archtops for years except for only having f holes.
We think anchoring the strings on a tailpiece has a different mechanical impact to taking them to the top. Thanks for commenting👍
If it isn't patented then why aren't you building at least some with the direct coupled bridge? If the emphasis is quality?
There are some traditionalist that do NOT like the looks of the newer Alvarez or Yairi bridges . It does NOT bother me , I have a couple of the masterworks guitars they are pretty good guitars . I'm NOT crazy about Alvarez pickguard shape and the AA on the headstock , Id rather have just Alvarez on the headstock and a pickguard design thats across between a Taylor , Guild , and Gibson design .
Thanks Todd, and you're right, some people do prefer the traditional approach. Thanks for watching!
A little disappointing. You don't tell us what material the Yairi bridge plate material is (some sort of composite but what?) and you don't speak to what sort of bridge plate design the Alvarez uses. The Alvarez would need some sort of extra support underneath than a traditional bridge plate or some modification in brace layout to compensate for lack of bridge strength.
Sorry, that bridge gives every guitar a sad smile.
one of the ways to get rid of the opposing forces of even the 2 part bridge is to bring the strings over the saddle as usual , and have the end of the string achored to the edge of the guitar somewhere above the end pin. That would put all of the downward force on the saddle/bridge.