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View Full Version : The Saddle, The Bridge and the glue and maybe the wood screws.



SuzukHammer
09-01-2010, 09:37 PM
I have a habit of asking dumb questions. Its not that I like asking dumb questions. I just don't normally think before I ask.

So... anyhow Its the saddle that transfers the frequencies to the wood, right? Its the basic need solution. I've seen instruments where the saddle is the only thing between the string and the vibrating medium. easy. no bridge and no glue. .... oh and sporadic intonation; but, what's the fuss with that???

So if you want consistent intonation, you need a bridge. I guess I don't understand why they don't just build the bridge into the top wood; but must be about economics and conserving the wood and that maybe some of that top secret tap-tone-testing-Area-51-stuff.

So they make the bridge and to me I'd think there'd be NO part of the bridge between the top wood and the saddle. To me the bridge is all about keeping the saddle in a certain position only, not a part of the transfer of energy.

But all the cheap ukes I've been checking, there is: 1) part of the saddle, 2) glue and 3) sometimes screws in between the saddle and the top wood.

Do the better ukes not have all that filler in between the tonal transfer? I mean is the saddle in direct contact with the wood?

BobN
09-02-2010, 07:21 AM
I have a habit of asking dumb questions. Its not that I like asking dumb questions. I just don't normally think before I ask.

So... anyhow Its the saddle that transfers the frequencies to the wood, right? Its the basic need solution. I've seen instruments where the saddle is the only thing between the string and the vibrating medium. easy.

On a banjo or violin, etc it is called a bridge

Archtop instruments have tops that are carved and are typically much thicker than flattop instruments.

A bridge on flattop instruments is an attachment point for the strings and is also a brace. The bridge is usually made out of very tough material while the soundboard (top) is usually very thin.

The saddle is usually a tight friction fit into the bridge slot. The saddle and bridge work together to transfer string vibration to the top. The saddle is used to adjust the string height.

Some of the antique Martin guitars had bridges made of ivory.
http://www.gruhn.com/photo/AB7726.jpg

Your idea is good and it would work with an archtop where the string ends are connected to the tailpiece.

Ukuleleblues
09-02-2010, 11:45 AM
If you could look into the uke you would also see a big piece of wood under the bridge glued to the bottom of the top wood called the bridge plate. It's about transferring energy to the top of the instrument and making it VVVVIIIIIBBBBRRRRAAAAATEEEEE.

SuzukHammer
09-02-2010, 12:34 PM
THanks for the input.

THis came about because I am painting (gasp) on some Mahalos.

I had also seen the result of a company selling ukes where the bridges came off the top wood and all I saw was glue.

And then I had read where some lutes built had movable bridges.

To me, I was thinking how to get the best transfer of energy because during my painting, I wanted to modify the bridge on the cheap Mahalos but in the end decided not to dislodge the bridge because it was so firmly set onto the top wood.

I am tempted to buy one of the failed bridges ukes and tinker.

Hey Ukulele Blues, THe big block under top wood seems counterintuitive to me too. THey talk about making the top wood thin to vibrate better, then you put a big piece of wood on that thin wood. It seems like a big bulky moment of inertia thing to me; meaning the largeness of it would hinder movement (vibration). It would seem that less would be more and that plate is not needed unless you want to plant some screws instead of or in addition to the glue.

I appreciate all input because some of this stuff just doesn't make sense to me or maybe I just don't understand it. And I am man enough to admit when my thinking needs to be righted.

SuzukHammer
09-02-2010, 12:44 PM
BobN,

So, you are saying on some intruments, the saddle is not needed and the bridge can be used to transfer the energy and provide the height of the strings?

BobN
09-02-2010, 01:53 PM
THanks for the input.

THis came about because I am painting (gasp) on some Mahalos.
Its not a big deal. You are adding some dampining, but not more sustain.

In plain English & very much simplified:
If I make a thick wooden top, it has lots of sustain but little volume.
It rings out for a long time.
If I build a thin top ( think of the extreme of tightly stretched goat skin)
It has tons of volume, but no sustain.

HEY!
somewhere there is a balance between Ethel Merman and James Taylor.





I had also seen the result of a company selling ukes where the bridges came off the top wood and all I saw was glue.



That is sloppy. The glue should not ever show.


check out hide glue. A hide glue joint will not come apart with heat as an epoxy or super glue(CA) or white glue (cassine) joint will. you can dissamble a hide glue joint with heat
+ moisture (steam).


To me, I was thinking how to get the best transfer of energy because during my painting, I wanted to modify the bridge on the cheap Mahalos but in the end decided not to dislodge the bridge because it was so firmly set onto the top wood.

transfer of energy on a plucked instrument is very inefficient.


I am tempted to buy one of the failed bridges ukes and tinker.

I started tinkering. It keeps leading to new "what ifs?"


Hey Ukulele Blues, THe big block under top wood seems counterintuitive to me too. THey talk about making the top wood thin to vibrate better, then you put a big piece of wood on that thin wood. It seems like a big bulky moment of inertia thing to me; meaning the largeness of it would hinder movement (vibration). It would seem that less would be more and that plate is not needed unless you want to plant some screws instead of or in addition to the glue.

I think that the bridge plate was developed for bridge pins. It helps to keep the ball end of the string from wearing the underside of the top.


I appreciate all input because some of this stuff just doesn't make sense to me or maybe I just don't understand it. And I am man enough to admit when my thinking needs to be righted.

IMO, you should tread lightly into these issues. -----------this part of my post deleted -----------------------

No, No, No. Your thinking does not need to be righted.

The best sounding classical guitars I have played had a slightt "dip" in front of the bridge and hump behind the bridge.
The tops looked to be on the "bleeding edge" of failure. But not really on the "bleeding edge". The builder knew what was goin on. A factory builder like Martin and Taylor Kayla, Lanaki cannot compete with smaller luthiers. The larger manufacturers cannot afford the time

IMO
Best thing is to find a local luthier that has students and do some classes. Build a uke. It's not a bad hobby. You will have something to show for your money. AND refine the focus of your idea.

Crap! I sound like I know what I am talking about!

Everything in my post is from the standpoint of a hack luthier, musician, composer and philosopher.

SuzukHammer
09-02-2010, 02:15 PM
haha.

actually, my wife wants to show me the temple where they provide vocational training. She hints that they make music instuments there and hinted I'd likely want to see what they have and maybe make some things.

I need to become more of a philosopher and less of a hack luthier!!

Like I said, I appreaciate your response. It will help satisfy my curiosity when I see differences in design.

Tread lightly??? haha. I'm a Noobie. You don't think I would be shot for asking these questions, do you? :)

DaveVisi
09-02-2010, 03:25 PM
This is my kind of thread. I like the technical aspects of instrument design.

Think of the bridge and the bridge plate as a "megaphone" helping to amplify the vibrations of the saddle. The saddle alone just doesn't have enough surface are to be a good vibrator.

If you look inside most classical guitars you'll find a bridge plate. They don't use bridge pins, so that blows that theory out of the water. It's there for a reason. I think that reason is to add stiffness so the bridge doesn't twist and damage the top, and as I indicated, helps to efficiently transmit the vibrations of the saddle to the much larger surface area of the top wood. It's that delicate balance between "bleeding edge" and total top failure that gives you the maximum efficiency.

SuzukHammer
09-02-2010, 10:02 PM
This is my kind of thread. I like the technical aspects of instrument design.

Think of the bridge and the bridge plate as a "megaphone" helping to amplify the vibrations of the saddle. The saddle alone just doesn't have enough surface are to be a good vibrator.

If you look inside most classical guitars you'll find a bridge plate. They don't use bridge pins, so that blows that theory out of the water. It's there for a reason. I think that reason is to add stiffness so the bridge doesn't twist and damage the top, and as I indicated, helps to efficiently transmit the vibrations of the saddle to the much larger surface area of the top wood. It's that delicate balance between "bleeding edge" and total top failure that gives you the maximum efficiency.

ok. I can buy into that.

To me, I think in terms of a speaker. Its got a circular cone and I could see that as a better sound shaper to that first cicular sound board top wood. It seems to me there'd be an optimal circular size and not a rectangle or crown shape but maybe that crown shape puts a certain voicing to it.

I also think in terms of hitting a wall with a hammer instead of a big piece of wood. THe hammer would seem like a brighter sound and the larger the area (like a piece of 2X4 wood )would seem more mellow. So I'd think there would be a certain variation in uke size and bridge size/shape.

My next questions were along the lines of: Could each indivual string have its own saddle and bridge? oi!!!!

Basically, I'm taking the simplicity out of the design, aren't I? haha.

DaveVisi
09-03-2010, 04:38 AM
Think of it... Why are trumpets shaped the way they are? Why a bell? Why not just a straight tube? It's the interface between sound source that needs to make the transition from small to big. In your speaker cone comparison, it's why we need cones in the first place. The coil itself is vibrating, but we can barely hear it, if at all. Of course Ukes aren't circular, so a circular bridge design wouldn't be right either. Look at a Kascha guitar's bridge. He tried to couple the different pitches of each string by using an asymmetrical bridge design. Does it work? Probably. Can I really, truly hear the difference? Probably not.

Regarding multi part saddles: Yes they can, and often do! My Alvarez Yairi classical guitar had this. My favorite undersaddle pickup design (not mine, I just like it) is six separate saddles, each centered over it's own pickup. Each is intonated separately, and you can even isolate the channels to separate outputs. One such layout is the "Hexaphonic" system. Something like this was used to build a MIDI guitar where each string activated it's own controller.

http://farm3.static.flickr.com/2455/3611664554_c9b5dd39b1.jpg

Ukuleleblues
09-03-2010, 09:55 AM
Seemed that way to me also but I was told by Howlin Hobbit it helps distribute the sound to the sound board.

I found the following stuff about the bridge plate in addition to it's there for Bridge pins:

http://kepasaukulele.com/head-to-tail.htm
Here is more info in a thread I found.

"While you certainly don't want to add any more mass than necessary to the center of the soundboard, adding stiffness in that location is a good thing. A stiff center area of the soundboard, coupled with low mass and a compliant surrounding area toward the perimeter of the soundboard, helps to create a broader frequency response so that the overtones will be propagated. With a limited frequency response, a uke sounds "boxy".

There is also a good structural reason for the bridge patch. It extends beyond the ends of the bridge and helps distribute the stresses that are concentrated there (a "stress riser", in engineering terms). If the bridge patch is feathered thin at its ends (to prevent creating yet another stress riser there), the soundboard will be much less likely to crack from changes in humidity."

http://uketalk.com/v-web/bulletin/bb/viewtopic.php?t=1701&sid=98053055f8926d0285002105b9df5203


"The bridge plate does what you mentioned, but also helps distribute the load from the saddle to the soundboard. There is a lot of stress applied to the SB by the strings rocking the bridge/saddle toward the neck. The tonebars help distribute this more evenly across the SB. Too stiff a SB is counter productive to what you are trying to accomplish. Finding that sweet spot where you get big volume, good sustain, and great tone is the Holy Grail that every builder is looking for. "