Bridge change

[LKN2MYIS]

On my Ratcliff "A" model, the bridge began the 'tilting forward thing' at the metal posts.

The bridges feet were seated squarely on the mandolin top
(typical thumbwheel-adjustable ebony bridge). The center part of the bridge, on the mandolin side, had an arch that is apparently part of the design. The bottom of this arch doesn't touch the mandolin top at all.

I bought a Cumberland Acoustic ebony adjustable bridge and had a local luthier do the replacement. When I picked it up, he had sanded the new bridge so that the entire bridge made contact with the top of the instrument. In other words, no arch that was inherent to the old bridge's bottom.

So, MUCH more bridge contact with the top of the instrument.

The issue is that the tone of the instrument has changed. Is this typical? I looked at it first and thought that it should probably make the instrument louder (I'm NOT a luthier, so this was simply SWAG). However, when I played it, the tone has definitely changed. Not in a bad way at all, just different.

Is it valid to assume that the amount of bridge contact with the top caused this (it was the only change)?

Any and all info appreciated. I did the mandatory 'search', but I'm looking for a bit more comfort, I guess.

Thanks to all in advance.

[F5GRun]

The contact of the bridge could have changed to tone a bit. But also it is a new bridge with differnt wood. The size, shape, and density of the ebony could be differnt than the original and the thumbwheels could be differnt size, although not much I would think. It all adds up and all changes the transmission of the vibrations from the strings to the top a bit. Im not as qualified as other on the message board but thats my two cents. I hope this helped.

[Fretbear]

Steve sells full-foot bridges like you describe as an option, Sam Bush has had his bridges fit like this on "Hoss" for a long time. The difference between buying it as an option (Steve is the only guy I am aware of that offers this option) and fitting a standard two-foot one this way is how much wood is removed from the bridge base, which I don't believe is excessive. Mike Compton has reported "having good luck with both kinds". I have one of Steve's full-foot bridges and love it.

[LKN2MYIS]

I don't believe that the amount of wood removal played that big a part. I believe (just an assumption, mind you) that it is indeed the full contact making the change.

I am not a bluegrass guy, and the instrument is plenty loud enough without doing any changes to make it louder. My concern is the tonal quality of the instrument, and I think that the additional bridge-on-top is the cause. I guess I just want to know if this is typical and to be expected.

I also think that the change might be more of hearing the D and A courses more. My reasoning (again, I'm NOT a luthier, nor do I play one on TV) is that the bridge is now making more contact under those 2 courses of strings, and it wasn't before.

Does that make any sense?

[Big Joe]

Anything you do to the signal path will alter the outcome. A full contact will have a different tone from a two footed bridge. As mentioned above, the density of the wood, the shape of the bridge and saddle, the amount of contact, the bridge width, etc. all affect the outcome. Only you can answer whether the tone is better to you. Often a full contact is used if there are issues with too much top sag. It can give more support across the top and help reduce the top deflection in some cases.

[Fretbear]

A single-foot bridge is not typical, the two foot-style is the standard as that is what was on Loar Master Models. Luthier John Monteleone had this to say on the subject:

The cut-out on the bridge base is also another area for consideration. How much of a cut-out is necessary? Well, I like the cut-out particularly for stronger tonal focus on the two tone bars. It will also work somewhat with X braces mandos but it is more effective with the parallel tone bars. You can also dispense with the cut-out to smooth over a situation of wilder imbalances of bass and treble.

[BlueMountain]

What probably happened was that the shape of your top was such that by the time the bridge fit perfectly, there was no space left. I've had this happen. Either one can sound wonderful, and there are a number of things you can do with a bridge that will change the tone. If you want that arch back, it's usually possible unless the bottom of the bridge is too thin. You only need a millimeter or two of space, you know--it doesn't have to be a quarter inch. Your luthier can probably do that for you in a few minutes if you ask. But you can't go back very easily. If you LIKE the new tone as well as the old one, feel free to live with it. Remember, before the adjustable bridge, mandolin bridges generally fit all the way across.

[LKN2MYIS]

Okay, here's an update.

I just spoke with the luthier. He ordered a pair of 'pins' (the metal rods that hold the bridge part and saddle part together).

When he gets them in, he'll take the ORIGINAL bridge bottom, put in the new pins, and use the ORIGINAL (or even the new one, I would guess) saddle piece. This should replicate the original footprint and get the original tone back. I could always swap out for the new bridge if I want - I'll have them both.

Again, I'm not necessarily adverse to the new tone, but now the whole process has my imagination tweaked and I'm real curious as to the changes taking place.

Does the above make sense?

[Kevin K]

The overall mass (weight) could be greater than the original bridge too which will change the tone.
The CA is supposed to be Loar spec'd and are a little heavier than what Roger Siminoff Loar spec'd bridge is. Not that one is better than the other just tonally different a little.

[LKN2MYIS]

That's interesting.

How much difference in weight could their possibly be? Or is it that even a tiny amount of weight difference would have such a great effect tonally?

[labraid]

There is also the factor of "tap". Does the old bridge have a bright and warm ping when dropped on a hard surface, and the new one a dull thud? Vice versa? A bridge is much akin to an internal brace. It must have strength, resiliency, and tonal capability. You can actually, and quite literally, tune the new bridge to match the old one, and get your old tone back. Just like anything else which takes part in tone production, physical dimension means next to "squat" (sp? ;)

G'luck on that.

[LKN2MYIS]

More interesting stuff. I was not aware that the bridge would
have the same type of tap-tuning as on other parts of the mandolin.

Honestly, I don't know if my ear could pick up such a subtle difference in dropping the two. It such a small piece of wood, and ebony at that, I would think that tonally it would be incredibly difficult to discern (at least for me).

[Geoff B]

I've noticed a mellowing of the tone when using a full fit bridge. I've also noticed with the two feet I get a little more clarity and note separation. I can't say why, but that has been what I notice with the same materials and the same mandolin but different bridges.

[markishandsome]

So, what do you mean "different"?

[Tavy]

So, what do you mean "different"?
LOL if you want him to describe tone in words that's going to be interesting (and hard!) #http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

A couple of observations from an inexperienced "instrument tinkerer": #Change in bridge material, size and weight all effect tone in subtle and unpredictable ways. #But also so does the height of the action, and the angle of the strings over the bridge (ie how much of the string tension goes into the bridge vs how much into the tailpiece). #The brand of strings you use, and whether you're using a heavy or light set will also effect tone: generally I find heavier (higher tension) strings to produce a more definite and less muddy sound, but your mileage may vary.

Actually, this leads to another observation: is the change in tone any greater than you get from a string change? #Are you using the same strings as before? #If yes, and they've been taken on and off a few times during bridge fitting do they need a change?

Just my 2c, John.

[LKN2MYIS]

Well, the bridges are VERY similar in size, shape, and are both ebony.

I realize that this doesn't mean that they are exactly the same, but I'll say they are VERY similar. New strings, J45's, same as has always been on this mando.

I'm curious how it wil sound with the OLD bridge base, new 'pins', and either the old or new upper saddle. I'm kind of thinking the newer saddle should alter tone on its own.

This whole 'experience' has been incredibly interesting for me. The change is definitely noticable.

[markishandsome]

LOL if you want him to describe tone in words that's going to be interesting (and hard!)

Huh? Folks describe tone in words here all the time. I agree it's not the most concrete thing in the world, but it's got to be more illuminating than saying that changing the bridge makes some sort of difference.

[LKN2MYIS]

I'm sure everyone's description of tone (or anything else for that matter) will be different.

I, for one, find it incredibly difficult to describe tone. I've heard others describe the tonal qualities of an instrument one way, and, to my ears, I wouldn't describe it that same way. I'd guess what some people might describe as a 'bright' tone, others might describe as 'tinny'.

Everyone interprets according to their own experiences. No way around that. I don't know if that is illuminating, but I think that's a fairly truthful statement.

In this instance, the tone is different than it was with the original bridge. I don't know if it's always a competition for which is 'better' or 'worse', but in this case it's simply different. I'm interested in what about the bridge change affected the tone.

With that in mind, here is an attempt at a description of the change that I hear.

The tonal shift is different than that which occurs with a string change. It almost seems as if there is more of a harmony to the tones. By that I mean that the notes seem to be less distinct, and more blended.

I have no real knowledge of the construction aspects (aside from my perusing this section at the Cafe). So this change kind of sparked my intereste in how the "whole of the mando is truly the sum of its parts" type of thing.

As someone suggested, swapping bridges around depending on your taste at any given period in time sounds like it might be fun.

If after the next change is made, the tone is back to the orignal tone, I'll certainly keep the other bridge to swap out if I decide I'd like to hear a different sound from the mandolin. I guess, again as someone else said, like changing picks as well. Everything affects everything.

I thank everyone for contributing to this post. It is very interesting and informative for me, and, hopefully, others.

[Red Henry]

I've done quite a bit of experimentation with the size of the center foot-cutout (or, to put it another way, with the length of the bridge feet). On most bluegrass mandolins, maximum response (tone and volume) seem to come with the bridge feet only 1" to 1 1/8" inches long. Feet 1 1/4" or 1 3/8" inches long, and especially if longer, can have a muting effect. In any case, it seems important that the bridge not exceed 4 1/4" total length for best response.

But this is not a universal rule, and applies primarily to Gibson-pattern mandolins. Instruments which stray from strict Gibson-copy specifications, Old Waves for example, may like different bridges. And any individual instrument may like a particular bridge best, a bit different from any other. I guess the moral is: Try several bridges, and keep the one you like best!

Red

[Manfred Hacker]

Hello there,
Like many of you, I have an adjustable bridge on my mando with the saddle resting on the thumb wheels a few millimeters over the base.
What would happen if I lowered the saddle so it would fully rest on the base rather than on the thumb wheels.
Big change in tone, sustain, projection?
Thanks for any thoughts.
Manfred

[Red Henry]

What would happen if I lowered the saddle so it would fully rest on the base rather than on the thumb wheels.
Big change in tone, sustain, projection?
Some people have reported an improvement in sound after doing this, but the difference is usually not dramatic. More improvement comes from eliminating the top/base discontinuity and using a one-piece bridge, if it is properly designed.


Red

[labraid]

Aren't violin bridges made with much discontinuity... on purpose? "Improvement" being very subjective in this case, in need of more precise qualifiers?

A funny note on psychology.
"I've been playing this mandolin for years, and yesterday I tweaked 'x' factor... What an incredible improvement in tone." = in fact, I was a little bored with the same old tone, something changed, and now it is different. I may improve it yet again next week, when I change it back.

Sorry, thinking again. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/smile.gif

[Red Henry]

Violin bridges I have seen (except for the ones with swiveling feet) are all one piece-- no wood-to-wood or wood-to-metal barriers. Of course, they are made in such a way as to process the sound before passing it on to the violin top-- this involves, among other things, few direct paths for the vibrations to follow between the string slots and the bridge feet.
# #Similar principles can be used in designing a good-sounding mandolin bridge, and maple seems to be the wood of choice here too, though some other woods work pretty well. Some examples, and reports from a good many bridgemakers, are given at #http://www.murphymethod.com/redbridge.html .

Red

[Moldrush]

I just had a full contact bridge base put on my mandolin this week. It did slightly change the sound I've been told by some luthiers that it can improve bass response. I also beleive after any kind of work like this to an instrument that it needs a little bit of playing in to reopen up before you will completely know what it will do. They also said that they use that alot in cases where the top may be a little thin to help gaurd against top sinkage.

[Dave Cohen]

When you think about vibrations in a bridge, remember that a bridge is an object of rather small dimensions. #Those "vibrations" that you are throwing around are not tiny little traveling waves; they are standing wave motions with wavelengths comparable to the dimensions of the object. #To understand something about those waves, you need only the most basic relation between wavelength and frequency:

frequency = speed of sound/wavelength,

or

f = c/lambda

The speed of sound in woods is typically about 3000 m/s. #So what would be the frequency of the lowest frequency motions in bridges? #Consider first a violin bridge. #Iirc, they are about 1.5" tall (+/-0.5"?). #1.5" is 0.038 meters (m). #So the lowest possible frequency for a full-wavelength motion of any kind, be it a bending motion or a compressional motion, would be

f = (3000m/s)/0.038m = 79,000/s = 79,000 Hz or 79 kHz.

The lowest possible mode of motion would actually be a half wavelength, so you could halve the frequency to about 39 kHz. #For comparison, the open E (1st) string fundamental on a mandolin or violin is about 660 Hz, or 0.66 kHz. #Quite a difference!

For a mandolin bridge at, say, 7/8" tall, the above relation gives an even higher frequency for the half-wavelength motion, ca 67 kHz! #For a typical guitar bridge, at maybe 0.5" tall (total), the lowest half-wavelength motion should have a frequency of about 118 kHz. #Do you think those high frequencies have a significant impact on the body and air motioins of a plucked stringed instrument? #I won't say absolutely that they don't, but you'd have to show me how they could, and given the disparities of wavelengths, that should be a pretty tall order.

What actually happens is that the vibrations of the string result in pulses of force at intervals of the frequency of the string. #the Fletcher & Rossing text ("The Physics of Musical Instruments", 2nd Ed.) has a good description of this on pp 241-245, in the chapter on Guitars and Lutes.

http://www.Cohenmando.com

[Fretbear]

I also believe after any kind of work like this to an instrument that it needs a little bit of playing in to reopen up before you will completely know what it will do.
This is really true, it has as much to do with unloading and reloading the top as it does the bridge modification. You have to let it settle and play in for a couple of days before you know what you've got.

[Red Henry]

...And sometimes, you find a difference which does not require playing-in. As mandolin-builder Peter Coombe said on CoMando after he first tried a one-piece maple bridge, "The difference is immediate and is not subtle."

Peter eventually settled on a good one-piece design in ebony as a standard bridge for his mandolins. The paper he wrote about the bridges is here: http://www.petercoombe.com/jaamim4.html .

Red


.

[Moldrush]

After having mine back for a week and playing it I'm really impressed with the difference it made for mine. My mando was pretty awesome to begin with but it really sounds great. again I just had a solid bridge base put on.

[peter.coombe]

Well I did not actually settle on a one piece bridge mainly because customers want adjustable bridges. I ended up modifiying a Brekke bridge to make it as close as practical to the one piece Ebony bridge, and it works. Sounds very much like the one piece Ebony bridge, and quite different from a standard unmodified Brekke bridge. The unmodified Brekke sounds somewhat dull and lifeless in comparison.

[jim_n_virginia]

LOL if you want him to describe tone in words that's going to be interesting (and hard!)

Huh? #Folks describe tone in words here all the time. #I agree it's not the most concrete thing in the world, but it's got to be more illuminating than saying that changing the bridge makes some sort of difference.
I've had folks hand me their mandolins and tell me they love the dark chop on it and when I play it to me it sounds bright and tinny.

Describing tone will always be colored by the tastes of who ever is doing the describing.

[mandolirius]

<Huh? Folks describe tone in words here all the time.>

True but rarely do they do a good job of it, myself included. Bell-like, ringing, woody, tubby....this is the language for describing tone, but it really doesn't say much. I think it is hard to do with words only.

[man dough nollij]

<Huh? #Folks describe tone in words here all the time.>
I put a new bridge on my McGillicuddy F6, and I find that it sounds supremely elegant, marrying New World opulence with Old World restraint, exhibiting full wood tonieness enhanced by hints of minerality and savory spice. Its lusciously layered tone portrays a singular eclipsing sonority of focus and primal posture unusual in less translucent bridges. Sounds pretty good, too. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/tounge.gif

[Doug Hoople]

<Huh? #Folks describe tone in words here all the time.>
I put a new bridge on my McGillicuddy F6, and I find that it sounds supremely elegant, marrying New World opulence with Old World restraint, exhibiting full wood tonieness enhanced by hints of minerality and savory spice. #Its lusciously layered tone portrays a singular eclipsing sonority of focus and primal posture unusual in less translucent bridges. Sounds pretty good, too. #http://www.mandolincafe.net/iB_html/non-cgi/emoticons/tounge.gif
I know exactly what you're saying, Lee. I can practically taste the sound of your mandolin from the meal in words you've painted here, and I must say it do taste mighty fine! At least, to my mind's palate, that is. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/smile.gif