Non-adjustable/adjustable bridges

[Mr. Loar]

Sorry if this was posted before.

Has anyone ever calculated the loss of sound/vibrations with adjustable bridges? I would have to think that non-adjustable bridges have advantages over the ones with thumbwheels.

[red7flag]

This issue has been discussed a number of times in the past. #You can do a search. #Red Henry (sorry bout the previous Murphy misprint, Murphy is Red's wife) is one that makes a fine non-adjustable bridge. #I would be interested in doing an AB with the same instrument with the two types of bridges. #Has any one done this and what was the result? #Thanks.
Tony

[Paul Hostetter]

I have done it many times. I know it's counterintuitive that there shouldn't be some evident loss with the metal posts and wheels, but many thousands of fine mandolins are out there with those bridges and their owners aren't remotely interested in switching. Which is why I checked, and continue to do so. Sometimes it's different (neither better nor worse), sometimes you can't really tell at all. Depends on the instrument a little, and on the prejudices of the listener a great deal. No one else's "test" is going to mean much, or even should. In any case it's neither rocket science nor a major expense to do one of each and make up your own mind.

[Mr. Loar]

Thanks. I do know that the difference is much more detectable with a larger instrument like a bass viol or even a guitar.

[Red Henry]

A great deal depends on the particular one-piece bridge you are trying. I think each mandolin and each bridge are different, but Peter Coombe, mandolin builder from Australia, said about trying a one-piece maple bridge, "the difference is immediate, and is not subtle."

My own experiments with bridges included a great many direct A-B (or A-B-C-D) bridge comparisons on several mandolins, because I can't see any other way to really find out something about bridges. I have tried about 25 different designs, and about 30 different woods, for making mandolin bridges.

Dozens of bridgemakers, and hundreds of maple bridges that I have made, have proved this out: http://www.murphymethod.com/redbridge.html

Advantages from a well-designed one-piece bridge will typically include a prettier, bell-like treble; more clarity in the bass range; a more even response from all the strings; more sustain; and often, significantly more volume.

However, as noted in the above post, many mandolin players are not interested in trying anything new, because they're used to what they have and don't want to switch. But the Gibson adjustable two-piece design (and their older one-piece design, for that matter) can be significantly improved upon, as far as tone and volume are concerned.

Red

[Paul Hostetter]

Au contraire, many have tried, and have gone back. And it's not because the one-piece bridges were badly made or fitted, or made from the wrong material. They just resulted in an unacceptable sound. Talk is cheap, and doesn't mean much. You only know if you try.

Re: basses - I have installed thumbwheels in probably about 500 basses (it's almost always to the same bridge). It's an essential to function for most players, not part of a quest for tone, balance, sustain, any of that stuff. Not once has anyone remarked that they heard a trace of a difference afterwards.

[Red Henry]

Whatever others are doing with mandolin bridge design, I've always had a primary goal of customer satisfaction. I have sold over 500 maple bridges, all with a money-back guarantee, and no one has yet asked for their money back.

Red

[first string]

A great deal depends on the particular one-piece bridge you are trying. I think each mandolin and each bridge are different, but Peter Coombe, mandolin builder from Australia, said about trying a one-piece maple bridge, "the difference is immediate, and is not subtle."

My own experiments with bridges included a great many direct A-B (or A-B-C-D) bridge comparisons on several mandolins, because I can't see any other way to really find out something about bridges. I have tried about 25 different designs, and about 30 different woods, for making mandolin bridges.

Dozens of bridgemakers, and hundreds of maple bridges that I have made, have proved this out: http://www.murphymethod.com/redbridge.html

Advantages from a well-designed one-piece bridge will typically include a prettier, bell-like treble; more clarity in the bass range; a more even response from all the strings; more sustain; and often, significantly more volume.

However, as noted in the above post, many mandolin players are not interested in trying anything new, because they're used to what they have and don't want to switch. But the Gibson adjustable two-piece design (and their older one-piece design, for that matter) can be significantly improved upon, as far as tone and volume are concerned.

Red

Obviously this is topic that you have invested a lot of time and energy in, and I am hardly qualified to dispute you. In fact, I am quite intrigued by the idea of the one piece bridge, and of maple as a possible material. I would point out though that Peter Coombe concluded that ebony imparts the best tone (if less volume).

For those who are interested, see:

http://www.petercoombe.com/jaamim4.html

[Bill Van Liere]

One of the reasons I am reluctant to try a non-adustable bridge is that I make small adjustments from summer to winter. Kinda hard to stop a mando from swealing up with moisture in the summer time.

[Red Henry]

Right, and an advantage of one-piece bridges is that they are comparatively cheap and easy to make, and it's easy to keep two or three in you case to use in year-round climate changes.

Peter Coombe did decide that ebony bridges sounded best on his own mandolins, and various other woods can be used when a mandolin likes them best. Cherry, yew, and other woods besides ebony all offer excellent tone and volume. For one particular harsh-sounding mandolin, a mahogany bridge was perfect in producing a mellower tone.

In any case, a good design, arrived at with thorough experimentation, seems to be the route to good sound. The design of Peter's nicely-made ebony bridges guarantees that they will be superior to the old Gibson solid one-piece design, which was actually a lower-cost retreat from Orville's original concept, as shown on these mandolins he made:

http://www.mandolinarchive.com/perl/show_mando.pl?3598
and
http://www.mandolinarchive.com/perl/show_mando.pl?2786



Red

[first string]

Interesting stuff Red. Thanks for the links. I've spent plenty of time looking through the archive, but hadn't seen those.

[Mr. Loar]

For one of my instruments I have two bridges; one for summer and one for winter.

[Fretbear]

I have tried a properly fitted one-piece maple bridge; the results were that the sound and tone was in every way inferior to an ebony Loar-style adjustable bridge.

[Red Henry]

Different mandolins will like one bridge more than another!

I've posted quite a few bridge responses, mostly from those who have tried maple mandolin bridges, at http://www.murphymethod.com/whattheysay.html .

Reports from over two dozen bridgemakers, most working in maple, some with other woods, are linked down the page at http://www.murphymethod.com/redbridge.html .


Red



P.S.-- Fretbear, if that was one of my own bridges, I hope that you will return it for a refund.

RH

[james condino]

Ken Cartwright wrote a nice article in Mandolin Magazine on this subject a while back for his Mando Medic column. He goes into detail about the history of bridge design and his experience using the John Monteleone's solid one piece bridge, the adjustable Gibson style and then a hybrid of the two ideas with the Brekke design. If you search the database for the mag., you'll find the issue.

I've installed hundreds of both styles of bridges and now it comes down to this: The customers that smile when I install a solid bridge get the solid one; folks that smile with the two wheels get that one....My personal preference is for the adjustable on my mandolin, a solid on my archtop guitars and mandocellos, and an adjustable on my upright bass. The reality is that my bias towards the adjustables is pretty much all about seasonal fluctuation and has very little to do with tone.

If any of the numer nerds(I'm one of them...) can lay out solid emprical results such as frequency and spectrum analysis, and ordely test data, I'll be glad to help you publish an artilcle on it.

j.
www.condino.com

[RevJB]

I have just made my own maple bridge and am doing my own A/B test. My initial response was very positive -- much louder with greater sustain (bell-like tones). But I hear odd overtones and buzzing. I am now reducing it to the correct height with better foot fitting. I definitely agree with Red Henry's quote that the results are immediate and not subtle.

[8ch(pl)]

I made some out of beech for my mandolin banjo. They are about 4 inches long and 5/16 in thick. I have not put any finish on them. Should I?

[Red Henry]

Since banjo bridges are customarily left unfinished, I would not think that any finish was necessarily needed. However, a light coat of stain or sealer should not hurt. Make sure, though, that no finish gets on the bottom of the bridge feet, and that there's not enough finish buildup to affect the weight of the bridge (if it is a light design).

Glen, are there pictures of your MB bridges available for us to see?


Red

[Dave Cohen]

Jim Rae and I did some admittance/accelerance spectra on several mandolin bridges fitted to a single test mandolin. The bridges included a Gibson, a few of my own style, a couple of Red Henry's one-piece (one maple and one ebony) and some experimental wedge-type bridges which I made something like D'Aquisto's. There was surprisingly little difference between the spectra for the different bridges. There were some minor differences, but I am not yet able to interpret them. I don't have any correlation with audition, except that neither Jim nor I could hear much if any difference. That doesn't mean much, though, since both Jim's ears and mine are at the far end of middle age. We took some spectra with each of the bridges on a rigid base, and some spectra with the bridges on the mandolin. Did controls with the shaker (impedance head) on the mandolin top plate near the treble side of the bridge, and then with the shaker at each string position on each bridge saddle. I'm capable of publishing the results myself, but I just don't think that there is enough to publish yet. Maybe I'll show the results to Rossing next time I see him.

http://www.Cohenmando.com

[ajh]

A couple years ago I went through the drill of making about a dozen solid bridges (one of which Red sent me gratis...thanks again, Red). I tried maple, a couple myrtlewood and an ebony. The maples were all sliced out of the same piece of straight quartersawn. I tried different body thicknesses, different "wings", different cutouts and different lengths to the bottom. I found a huge difference given different variables. The myrtlewood sounded really brash. The main problem is that for the A/A testing, you shouldn't use new strings....and if you are changing bridges you eventually do break the e and a's. BING! Then where are you? I eventually did find one I liked quite abit, but then started playing around with the ramped Brekkes with some modifications that I got from Peter Coombe (thinning the body and shortening the legs) and wound up going that way. There are so many variables that it really does become a LOT of labor....along with the fact that you are putting wear and tear on the mando itself.

YMMV
Tony

[Red Henry]

Bridge experiments are a certified hassle. As you can see on my website, I went through over a hundred bridges working out variables and arriving at a bridge design which would sound good on all the mandolins I tried it on (A, F, oval-hole, f-hole, and flat-top). This took a lot of time, but I am confident of the bridges I send out, and the customer responses have justified all the work in making and trying about all those experimental bridges.

I do not see how someone could make just one bridge of one design and judge maple bridges as a whole from it, but some of them have done so. As you can figure, the results from just one try will usually be negative, as with a one-off bridge tried by a well-known bluegrass manufacturer, or inconclusive, as with an extra-rigid, super-light maple bridge made by an expert instrument repairman who posted it on line.

As you found out, there's a whole lot of difference in even small changes between one maple bridge design and another, just as there's a lot of difference between one adjustable bridge and another. I don't think that either type should be judged from just one bridge.

For example, should anyone reject the idea of an adjustable bridge when they may have tried just one cheap or worn example, and they haven't ever tried a very nicely-made, good-sounding bridge made by Steve Smith or Randy Wood or another of the fine bridgemakers? I don't believe so, and yet some folks have tried just one maple bridge-- and not one designed by any extensive course of experimentation-- and judged all maple bridges from that.


Red

[peter.coombe]

Since my name has been mentioned a bit in this thread, I think I should clarify a few things. I can hear big differences between Maple bridges and Ebony bridges, and it is consistent. However, as Red has said, it does depend on the instrument, but on my mandolins I much prefer the sound of Ebony. The reason I went for the Brekke is because customers want adjustable bridges so they can adjust the action to suit them, not me. I really think Red is on to something, just the small modification of drilling 2 holes in the Brekke bridge saddle does make a surprisingly large difference to the sound. However, once again, it does depend on the individual mandolin. Some of my instruments have greatly improved tone after this treatment, others hardly at all, but I have never had one sound worse. I have tried to get the best of both worlds with my modified Brekke. It is an adjustable bridge, with the benefits of some of Red's research. I have tried a Maple Brekke that STE kindly made for me to test, but still preferred the sound of the Ebony Brekke.

[Bertram Henze]

Excuse a physicist's 2cts (all theory covering a tiny part, therefore proved wrong easily with other border conditions):

The purpose of the bridge is to transport string vibration energy to the soundtop. There are two obstacles that can disturb this:

1 - material hardness borders: sound speed depends on how hard the conducting material is; a border between differently hard materials will cause part transmission and part reflection - the bigger the difference, the more reflection you get, but that's exactly what we do not want. Problem: the strings are hardest, the spruce top is softest, so ideally material hardness should decrease slowly on the way. This is simulated by making the bridge wider near the soundtop (longer beams are easier to bend and thus act like being softer).

2 - contact problems: in a one-piece bridge, we have two places where contact between sound conductors can be insufficient: the saddle grooves (string-to-bridge) and the bridge base (bridge-to-soundtop). We all know how bad grooves can ruin the sound, but that is surprisingly easy to mend, compared to the bridge base: it is not at all easy to have ideal contact over such a large area. Typically, the break-in process takes care of this to a certain extent.

Of these two, number two is the more critical, because the material hardness differences within the bridge are always small compared to the soundtop-to-air difference which cannot be changed anyway. Therefore, good and bad of thumbwheel mechanisms depends mostly on god and bad of fitting and precision.
One interesting point I found on Red's website were the experiments of trimming out the middle of the bridge base, thus putting the bridge on two smaller feet. This is bound to concentrate the pressure of the bridge into a smaller area and thereby to improve the bridge-to-soundtop contact (kind of a break-in accelerator).

I guess the ideal contact bridge would be directly carved out of the block together with the rest of the soundtop, thus taking mandolin prices to fresh heights of unreachability.

Bertram

[Fretbear]

Just for the sake of discussion and speculation, as there are no definitive answers to this topic.
It is interesting to note that in all cases, whether one-piece or adjustable, that it is always desirable to have a void somewhere between the strings and the bridge base. In a one-piece, this is the double joined cut-out, in the adjustable, it is the space between the saddle and the bridge base. The CA adjustable that I use has a continuous foot (no centre cut away as is usually found) While my particular self-built mandolin is a good one, the almost alarming volume without loss of tone that I get from it was only achieved once I settled in on this particular (tall-boy) bridge combination. Most adjustable bridges have the two-foot cutaway design because the classic Gibson F5's did, but I believe with an adjustable the single-foot base driving the entire top as well the two tone bars can play an important role in both volume and tone.

[Bill Snyder]

...I guess the ideal contact bridge would be directly carved out of the block together with the rest of the soundtop, thus taking mandolin prices to fresh heights of unreachability.

Bertram

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