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Mattia & Michael...

My (quite possibly flawed) thinking about the Yairi string anchor is that they've taken out a piece of sound-distributing straight grain and plugged it with a chunk of hardwood. Yes, the bridge and bridge plate are hardwoods, but they also act as braces, and their straight grain helps (as I understand it) to distribute string vibrations across the top. It seems like that separate plug stuck through the soundboard would act like a wall to sound distribution. Of course, that small piece of top area may be inconsequential compaired to the full area of the top, but maybe not. Just one of those little details....

For what it's worth, I was actually playing guitar last night with a partner
who was playing an Alvarez with that very bridge design. It was a dred
body and sounded fine. Nice full sound. Wasn't as bass-y as my jumbo,
but I still liked it.

Mind you, that's one data point and from an admittedly poor ear, but it's
not like the bridge made the guitar sound like an unplugged electric or
anything.

Let me put it this way - I have an Alvarez in the case at my feet right now
which hasn't been played in six years because the bridge is lifting and
made the action untenable. I'd rather have that two-piece bridge and be
able to play with an altogether reasonable tone than to have my broken
axe languishing away in its case...

Jay

Jay. The one with the bridge lifting is it a Alvarez or a Alvarez Yairi. and if it is an Alvarez is it a proffessional series or the Artist series The reason I ask the Artist series have had a bunch of issues like this but they are a entry level instrument. The Proffessional series are very good all solid wood guitars and of course the Alvarez Yairi are all Hand builts

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Scott van Linge38749.6825694444

Scott, I understand what you're saying, but look at my bridges. Very square corners.

I'm a 3rd generation woodworker, and my Dad would slap us if we took sandpaper to an edge or corner. He was also a machinist, and instilled in us a love of the beauty of a well defined edge in a well machined part, steel or wood.

I cannot make rounded bridges or braces <bg>

So if your theory is correct, my guitars would lack trebles, from the square and sharp-edged bridge, as well as all the bracing that gets little sanding, and much planing(comment once heard is that we can cut cheese on the back braces). Even my side braces are triangular in shape and sharpened to a knife point. End blocks are machines to sharp, crisp, bevelled edges. Yet, treble is not something my guitars lack; if anything, I have too much, bordering on brash. And losing them when moving up the neck also isn't a problem, as my tone and volume is strong and consistent all the way up the neck, often gaining volume and tone as you move up.

Now, your work may indeed yield great results, but I have to question why the results are what they are.

no postScott van Linge38749.6837962963

Have you swapped the rounded bridge for one of equal mass, but with squared edges, then swapped again? How many A-B tests have you done on the same guitar? I'm not talking of changing a huge moustache bridge to your small one, but two of equal mass, yet different shape?

You talk of corners absorbing energy, but again, every aspect of my build has a sharp corner, and yet lack of energy is never a problem.

I'm not questioning that your work yields what you say it does, but I'm more apt to believe it is due to lowering the mass than rounding the edges.

As I say, any more treble from my guitar would require a coil pickup and a "Fender Champ" amp <g> One writer for Acoustic Guitar magazine refered to a particual one that he tried somewhere as "an acoustic telecaster", refering to how loud and bright it is. Honest, I often find myself working on the guitars to warm them up a bit before they leave here, for being overly bright and loud, being more brash than anything. I cannot see anyone wanting more treble. Of course, these are steel string guitars, and not classicals. I would expect the nylon strung guys to have a whole new set of rules.

[QUOTE=MichaelP] Jay. The one with the bridge lifting is it a Alvarez or a Alvarez Yairi. and if it is an Alvarez is it a proffessional series or the Artist series The reason I ask the Artist series have had a bunch of issues like this but they are a entry level instrument. [/QUOTE]

It is certainly an entry-level instrument. It is an Alvarez, and not an Alvarez Yairi. I don't remember specifically anything regarding "professional series" versus "artist series", but between the two I would guess it's of the artist series. The model is 5212B, about 1994-ish vintage.

Not to hijack the thread, but if I were to repair this lifting bridge, I'm thinking I'd maybe heat a knife with a torch and stick it under the lifting bridge to try to melt the glue and pry it all the way off. Then scrape any remaining glue off the body, resand the bridge by attaching some sandpaper to the body, and then regluing the bridge. Does that sound about right?

no postScott van Linge38749.6850115741

yea but you would be better off to heat the intire bridge with a bridge iron first to lossen the the glue. Your knife will loose it's heat qiuck. Also determine the runout direction of the tops grain. One half will be one way the other will be opposite if book matched. You want to go with the runout to avoid tearouts.

are you using ebony for your bridges?

Nope. Brazilian RW is my standard.

I've swapped the bridge back and forth on the same guitars(test mules, I call them), and every time, Brazilian sounded better, brighter, with better note-to-note seperation. I also like African Blackwood for bridges; nicer, more interesting tone, but with a slight volume penalty(both likely due to its greater mass for the same size)

I've also shared much information with Bryan Kimsey, where we both swapped bridges back and forth on the same guitar(we shipped it from Northern Ontario to New Mexico and back; that kind of tells you how seriously we take our experiments), and only shared our writen findings once both of us had done our tests. We also changed a ton of other stuff on the same guitar, but the bridge swap was the first. Our findings were identical, and were exactly what I'd seen on other test mules.

I'll use ebony if a) the client insists, or b), if the client is a rhythm-only player, because I've found ebony to blend the notes together better which sounds "smoother" for a rhythm player.

I'm sure you attain great results; I've hot-rodded many a guitar, too. I'm not questioning your results, only your thinking as to why the results are what they are.

You really need to do some calculated A-B tests, on the same instrument, and on various instruments, to come even close to a solid conclusion. Take that Gibson, take the bridge off(takes 5 minutes...), weigh it, and make one from the same material, but shaped rectangular, to the same weight. Stick it on and play the guitar a month. Then swap the bridge again... this kind of stuff is what we need to do if we wish to be taken seriously. Anything else is pure speculation and calculated guessing...Mario38744.7431134259

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Scott van Linge38749.6875925926

Had my shields up...

It's all good, as long as it works in the end.

Great thread you geniuses!

Don't know if I should run for cover or not, but within (I hope) the next 2 months, my first guitar with this type of bridge will be done. The almond-shaped bridge is about 1-1/4" x 5-7/8" (I know it looks bigger than that.) It is a pinless bridge, except the strings continue back and attach at the butt (it could use a tailpiece, but I made this tail-less.) The bracing in blue is a radial soudboard bracing pattern, and the red braces are all below the soundboard (structural - to hold most of the string force.)

I know I showed this here in another thread a while ago, but thought it might be an interesting addition to this thread. (Or, fodder for snickers.)

Even if this particular radial bracing scheme and/or bridge shape does not do what I hope, I am guessing that the concept of creating two distinct sets of braces - sonic, and structural - is a good concept, and could free up the acoustic design potential of the top.

I know this is more than just a bridge, in a bridge topic, but with this concept, it's a system with (at least the structural) bracing.

OK, I've got me helmet - let 'er rip!

Dennis

Body Plan Section



Section at Bridge (widest point)

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Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

I agree too, i would like to know more on this, it seems to make good sense. If you can Dennis, will you post pics of the building part ?TIA

Serge

Granted I've only built one guitar, but I did sand and re-sand the bridge, test and re-test as I did this and I was amazed at the difference every single time. My limited experience tells me there is something very important going on in this area. I used an ebony bridge and I noticed volume and tonal changes from E to E string after very small shape and weight changes. Interestingly enough I lost a bit of Bass from these changes(Original bass was tremendously special), treble seemed fairly consistent, note seperation improved, clarity and sensitivity improved. I started off at 28 grams on the bridge, sorry not sure where I ended up but quite a bit lighter that is for sure(I sanded a lot of wood off). I actually followed many of Scott's suggestions when building this guitar, except the bridge which I gave some edges for looks. I eventually rounded the edges as the sanding got going, I think my next bridge will be Rosewood and more almond shaped, if you will. All I know is that every LITTLE change MAY make a huge difference in the tone and volume across the board.


Greg

_________________
Gwaltney Guitars

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Scott van Linge38749.6901388889

Hesh,

When I read Siminoff's book, and saw the apparatus that he used to determine the bridge's motion (mostly rocking, neck-to-tail), a light bulb went on in my head. I wanted to try a design that would not inhibit that motion. The tall transverse brace beneath the saddle is the only brace that crosses the bridge patch area, again to promote the pivotal rocking motion.

Serge,

I'm trying to document the whole build, and would be happy to share it (even if the result is poor, because we can all learn from each others mistakes.)

Scott,

All the sonic braces are 1/4" wide. Other than the tall transverse brace, all the radial braces are really dimimuitive. The radial braces start about 1/8" overlapping the bridge patch, and are an attempt to distribute the bridge energy without inhibiting the bridge's rocking motion.

Dennis

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Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

Thanks Scott,

I'm going to look at the bridge again today, might even sand some more...Yikes! It really does sound amazing, but that elusive place is out there somewhere, what the heck if nothing else I'll learn something here. I'll let you know what happens

_________________
Gwaltney Guitars

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Scott van Linge38749.6889583333