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I know it's been discussed here before but ......... What are the effects of a guitars bridge on sound and sustain? If a bribge is of equal size and shape will it matter what material it is made from? Is the difference just because of the weight of the wood? Or do some woods promote certain tones?

How much should bridges weigh? (Range Please)

My typical bridge is made from Mad Rosewood and weighs about 29g before it has been slotted and drilled. (Probabaly about 25-26g after drilling and slotted)

Is that heavy? Causing what effect?

Thank you for your patience and forethought

Joe

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Joe Beaver
Maker of Sawdust

If you think about the bridge as the heaviest, and one of the stiffest, braces on the top, then the effects changes in it will have on tone should follow. The top is not a simple thing, of course, and neither are the effects of even a simple alteration on the bridge. But you can make some useful generalizations.

All else equal, making the bridge heavier should drop the top resonant pitches and cut down on the treble response of the instrument. The effect is usually heard as a 'bassier' sound.

Again, with all else equal, making the bridge stiffer should raise the resonant pitches of the top modes, and cut down the low frequency power.

I'd say that 25 grams was a tad on the heavy side for a classical bridge ,and light for a steel string, but that's only my opinion.

25 to 30g is about normal for a steel-string bridge.
Damping is the important factor, ebony having more damping than, say, Braz. To my ears an ebony bridge, all other things being equal, yields perhaps more sustain and a more solid tone. A lighter, more resonant bridge material (like Braz or EIR) sounds more "open", or "airy". For my bridges the difference between ebony and Braz is about 6g. Cocobolo, HRW, ziricote and other "heavy" tonewoods are about equal to ebony in weight, but with much less damping.
The shape and footprint probably have more influence on tone than the material used. Up to a limit, a smaller footprint is better for tone, but then the gluing surface must have enough strength to counteract string tension, and support the top/bridgeplate there.
The thickness and scoop of the wings control flexibility.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

To see the effect on tone the bridge can have may easly be seen if someone has a guitar that they think may have a too heavy a bridge by taking some weight off the bridge while still on the guitar . This of course may reduce the stiffness of this brace,but in a disproportionate amount compared to the weight loss.The area of the top in the bridge location is a very sensitive portion of the guitar.Weight gained or lost here can have a large effect on tone.As to size ,the smallest that would be safe would be about 1"by 6"and only on the stronger woods such as red and sitka.Also in play are things like damping and the use of such woods as BRW to add some brightness. Just my 2 Canadian cents worth.Worth less then 2 U.S. cents. The Canadian buck is still down.

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A person who has never made a mistake has never made anything!!!

For an idea of the differences in weight, I made five bridges this week with a new design. All are pretty close to identical in dimensions. Below is a pic with a standard LMI bridge. Weights as follows.

LMI Ebony - 40g
Ziricote - 26g
Mad Rose - 30g
Coco - 32g
Af Blackwood - 36g
? Ebony (I'm assuming African)- 36g

The Coco and Blackwood may still be a tad wet. We'll see if they get any lighter after sitting around for a while.

I hate Ebony bridges because of the weight and damping. I will usually only use Ebony with a pyramid bridge. I done a bridge experiment a while back with a Sitka/Mahogany Slope D. I played the guitar for a month with three different size and weight bridges. (all BRW) The first bridge was a straight bridge, 6"x1" similar to an Advanced Jumbo bridge. It weighed 24 grams. The next bridge was similar to a "belly" bridge, but it wasn't as wide. It was 1 5/16" x 6" with 1" wings. It was tapered, or thicker on the bass side instead of just rounded on the top. This is my "standard" bridge design. It weighed 32 grams. The last one was a huge bridge that looks similar to a Taylor bridge. I didn't intend it to look "Taylorish" that's just how it turned out. It weighed 44 grams. With the lightest bridge the guitar was.......lively, but it was kinda thin sounding, without much bass. With the middle size and weight bridge it sounded good, to me. The tone was balanced and also had a good balance between volume and sustain. With the BIG HEAVY bridge it sounds like it's stuffed full of socks. It's not loud, it doesn't really have much sustain, and it's got no treble. I had recordings and pictures but I lost them when a hard drive died. (Keep backups of all your data.) Someday, when I have time I plan on removing the anchor, re finishing the top and going to my "standard" bridge. The guitar has 1/4" scalloped bracing, with a Honduran Rosewood bridgeplate. I believe the lightest bridge would have probably sounded better with a Maple bridgeplate, and the big bridge would sound better with heavier bracing.


I don't think theres a right or wrong bridge size, shape, weight or material, but the bridge needs to work with the rest of the guitar.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

I think one should read Al's comments more intently. His point is that this is all a part of a system and that density and stiffness of a bridge alone will not be determinant of it's affect on the sound of an instrument, but rather within the context of a particular overall design encompassing all the subconscious decisions that builders make. My bridges are ebony and are bigger than some, particularly on my baritones, and it doesn't have a deleterious affect on the sound; they might in the context of another's building.

From what I've been learning and read here it seems to me that the bridge should be thought of as a specialized brace. And from what Alan and the other have said it goes with stiffness and weight and dampening effects from it.
So this also raises a question in my mind. Here we go and voice a top and then after appling finish glue the bridge on.
I guess that's a chance to either tweak the top in or screw it up.

In response to Zac's post, one can't stress enough not to rely on standard densities. If you're interested in weight, weigh the piece you have. I for one have two cnc machined identical bridges, one ebony one EIR and they both weigh the same. I then have some African Blackwood I bought to use for bridges and it is significantly heavier then the Gaboon or Macassar Ebony I have. Then I have some Madagascar that is much lighter than any other rosewood I have.

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David White, Toronto

"All my favourite singers can't sing."

When we are talking about weight are we really talking about how weight coresponds to dampening which is probably related to the density of a wood and the different species dampening qualities. Seems like a somewhat stiff bridge might be better at transferring the string energy to the top and moving the top. I would think that you might want a solid center to drive the top. I don't think that the weight of the bridge is a load factor on the top since the strings are trying to pull the top out at that area. I might be wrong about my logic so if I am help me out.

Very interesting replies. As usual there is more than meets the eye. When I make my standard bridge out of ebony it comes in at 35-38g. I've never considered a bridge as part of the bracing but I can now see where it is a very big part. I use a maple back plate, 1/4"x5/8" or 3/4" scalloped, forward shifted bracing. I've used the same bridge on my jumbo and small jumbo with very little thought except with regards to how it looked.

My bridge is 6.5"x1.5"x3/8".

Here is a picture of it. I slot and drill after it is on the guitar. That allows me to easily change string spacing.
I believe I'll pay more attention to bridges in the future.

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Joe Beaver
Maker of Sawdust

I didnt make all five of my bridges with the intent to compare weights, but after I weighed them I was a bit surprised at how the compared. I didn't expect Ziricote to be significantly lighter than the others. I always had the perception that it is a heavier wood. Maybe this is just a light piece. I expected the mad rose to be the lightest and african blackwood to be lighter than it is. Coco was a bit lighter than I expected. I guess you cant assume somethign about a piece of wood, there all different.

Woody mentioned Taylorish looking bridges. While designing my own bridge, my Taylor was one of my comparisons. Their bridges are HUGE! I never noticed it before. Close to 1-7/8 wide and rather thick throughout.

Zack

I know what you mean about the weight of woods. I was supprised when I weighted this Mad Rosewood bridge. Usually I slope the back of the bridge some but this on was already on the light side. I like the looks of your bridges. do you use the same pin spacing for all of yours?

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Joe Beaver
Maker of Sawdust

I wish I knew more about the effect on tone of the damping factor of bridge material. It sure seems as though it ought to matter, but how do you do the experiment?

I don't see any correlation between damping factor of the material and density. African ebony is dense and has high damping, African Blackwood is dense and has low damping. If there's any correlation it's usually the lighter woods that have the higher damping, but then again, the black locust I've measured is less dense than most Indian rosewood, but has lower damping, so.....

The bottom line is, as has been said, measure, and take notes.

Thanks Joe. I took some time to come up with my own design that I was happy with that didn't look too much like a copy of someone else's. It was influenced by Taylor, John Mayes and Hesh's bridges. I wanted something that was along the lines of a traditional bridge, but with a little different feel. Not too different or ornate. After a bunch of sketching I drew it up in Autocad. Its really rather simple. one straight line and all the curves are the same radius. 6.5x1.5x.0360

I use 2 1/4 on most except for OOO, OO and O. Those are pyramid bridges with 2 5/16.

Something I did earlier this week may actually be pertinent....

My factory Tak -- It sounded so good when I first got it... then I built 2 guitars... and it sounds dead compared to both of them... so I decided I would poke around and see if I could do something about it.

Now.. Bridge weight has a giant effect on the sound of the guitar... so knowing this, I removed the bridge bolts. 5 g of steel and brass... In theory, this should have changed the Mass of the bridge without really changing the internal damping of the wood... as the bridge footprint didn't change.

Well... The effect was amazing. A huge difference in Tone and Sustain by just removing those weights.... but it did change the balance of the instrument as well... pushing the balance towards Treble/Midrange.

Instead of trying a range of weights and dampings... it is probably better to try 2 at the extremes... Super high damping and Super low damping if possible... Maybe a particle board bridge and an Aluminum bridge or some such beasts... as it lets you get enough effect that it is either obvious or doesn't exist... because if a particle board bridge sounds the same as an aluminum bridge with the same weight -- it isn't the damping that matters.

Good luck with your experiments

John

Damping and weight have different effects on tone, and are not necessarily related.
The footprint of the bridge, its size and where it intersects the x-braces have far more importance.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

There you go. I thought they were. How does one check or test or measure for the dampening of a wood? Seems like something worth recording.

Very timely thread as far as for a current experimental build that I'm doing.

I am close to finishing a WRC over Hondo Mahogany OM which will have an Indian Rosewood bridge (my first attempt at IRC for bridges). The density of this particular IRC seems to be very low compared to other materials I have used and as a result, the weight is almost half that which I have previously used...(15 grams vs. 25 grams) I'm looking forward to the results and will even add weight (coins) to the bridge to observe tonal changes.

Any predictions as to what I can expect?

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JJ
Napa, CA
http://www.DonohueGuitars.com

JJ

It would be interesting to hear what effects you think the light bridge has on sound of the finished guitar.

Joe

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Joe Beaver
Maker of Sawdust

In my experience, when talking about the weight of the bridge, you really need to consider the weight of the bridge patch with it. Bridge patches can vary a lot from one builder to the next so it's not particularly helpful to to talk about the bridge weight alone.

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http://www.chassonguitars.com

Kent,

That makes sense. I've heard bridge plate materail matters. Darker sound with rosewood, brighter with maple. Maybe some or more of the difference in sound of the back plate comes from the combined weight of the back plate and the bridge. Good point.
Joe

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Joe Beaver
Maker of Sawdust

I read maple more bass then RW.

Chris

You may be right, the memory is not what it use to be.

Joe

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Joe Beaver
Maker of Sawdust

I still need to build the bridge for my first. Any reason I shouldn't use cocobolo? It's pretty dense but I don't think it's as heavy as the ebony I have.

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Steve Smith
"Music is what feelings sound like"