CA bridge vs stock bridge

[John Adrihan]

What makes a CA bridge better than some stock bridges and not others? Specific example: I have read discussions that say to improve a Loar brand 600 or 700 to replace the bridge with a CA bridge, but I have read that the Kentucky bridges are fine. There are probably other examples also. Any way just wondering, are they fitted better from Kentucky or is there such a thing as better ebony? Thanks for any replies.

[bart mcneil]

You are going to get some differing opinions on this subject. But i would suggest that a Cumberland bridge is pointless for a beginner and simply a means of increasing the price of a new mando by selling you a more expensive bridge when you can do quite nicely with the original bridge supplied by the Kentucky manufacturer. It may or may not be an improvement but its cost suggests that its biggest improvement will be in the sellers bank account. one of the features discussed about the Cumberland bridge is that it is better fitted to the instrument than the original bridge. But any bridge, cheap or expensive, can be made to fit the Kentucky (or other brand) as well as the Cumberland bridge. So what makes it worth so much more money? I dunno.

[Tom Coletti]

Bart brings up a good point. When people replace stock bridges with new bridges, I always wonder if the added benefit was from a proper fitting and slot filing on the new bridge as opposed to the material or design of the new bridge itself. Really the only way to tell would be to have four bridges tried on the same mandolin: stock unfitted, stock fitted, new unfitted, and new fitted. Or perhaps it's because a lot of entry-level bridges are often made of rosewood, and the player just prefers the sound qualities of ebony.

Regardless of how this debate ends up, according to the Tichenor Paradox, Cumberland Acoustics should get a huge boost by the thread's end. Have fun, guys.

--Tom

[multidon]

There are different types of ebony each with different properties. Indian ebony is less hard and dense than the others, brown ebony and Brazilian ebony are the hardest and densest, and Gaboon and Macaasar ebonies are in between. I don't know what type most bridge makers use. I don't know what is better for a bridge, but my guess would be denser is better. I am just pointing out there are differences with different species of ebony. They are not all created equal.

[Dave Cohen]

There are different types of ebony each with different properties. Indian ebony is less hard and dense than the others, brown ebony and Brazilian ebony are the hardest and densest, and Gaboon and Macaasar ebonies are in between. I don't know what type most bridge makers use. I don't know what is better for a bridge, but my guess would be denser is better. I am just pointing out there are differences with different species of ebony. They are not all created equal.

That's the 2nd time that I have seen "Brazilian ebony" mentioned recently. I must be missing something. Can't find it in the Wood Database, or anywhere else. There is a "Texas ebony", which is an ebanopsis genus, hard and heavy, but not a true ebony.

Second point: The densities, hardnesses, and Young's moduli of any given species can vary pretty widely. The numbers you see in places like the Wood Database, Hoadley's text, & etc., are averages. What you usually don't get are the standard deviations or ranges. I routinely determine the densities of wood samples that come through my shop. F'rinstance, the range of walnut samples I have seen so far is very wide. I have seen walnut samples with a density as low as 0.43 g/cm3, and other walnut samples with a density as high as 0.72 g/cm3. Same with maple. I have seen a few Bigleaf maple samples w/ densities at ~0.5 g/cm3 or slightly below, and a birdseye maple sample w/ a density of 0.78 g/cm3. Similar variations in ebonies. I have seen some samples of W. African ("Gaboon") ebony that were denser than most sample of Macassar ebony, and some samples of Macassar ebony that were denser than most samples of W. African ebony. W/ both of those species, I have measured densities as low as 0.85 g/cm3, and as high as >1.1 g/cm3. I suspect I haven't yet seen the extremes.

3rd point: Hardnesses and stiffness (i.e., Young's moduli) roughly track the densities, but even there, there are exceptions and outliers. If you determine densities, you may find some low-density pieces of wood that are especially hard & high modulus, and vice versa. At this point, I am not sure whether more dense or less dense is better for a bridge. I generally favor lower densities, as I favor low bridge masses. But, I could be wrong.

[Pete Jenner]

I've said it before and I don't mind saying it until I'm blue in the face. West African ebony is Gabon ebony not Gaboon ebony. It's named after the country, Gabon. It's not difficult.

[Larry Simonson]

For many years I have read claims that a well fitted bridge bodes well for the best performance of a mandolin but I have not seen any experimental results to that affect. In case I missed it, could someone point me in the direction of these results?

[Ivan Kelsall]

CA bridges are very well know as a well made,reliable & good sounding bridge. Whether they will add or detract from any given mandolin's tone/volume, can only be determined by fitting one.The main reason (IMHO), that people recommend them, is that if you fit a CA bridge,it is of a 'known quality' & should produce a good result when fitted. That does not mean to say that a CA bridge will improve all mandolins.That is very much dependent on the quality of the mandolin to begin with,but it might do.
From Larry above - "I have read claims that a well fitted bridge bodes well for the best performance of a mandolin but I have not seen any experimental results to that affect.". It's not down to any experimentation. Luthiers & Violin makers have understood for centuries that all musical instrument bridges should be well fitted right from the off. It's when a bridge isn't properly fitted that the problems arise. It's the same for anything that's 'fitted' for a purpose,if it's not done correctly,it usually doesn't work properly,
Ivan

[multidon]

My apologies to Dr. Cohen, Pete, and others for passing along what seems to be somewhat erroneous information. I used a commercial site to get my information. Upon further research it seems Brazilian ebony is not a true ebony but has that trade name for its dark color. Pete, Bell Forest Products uses the name Gaboon not Gabon.

As someone who is not an expert but does like to do research I am only as good as my source material. Lumber trade names can get confusing. Still trying to figure out things like Brazillian "cherry" Philippine "mahogany."

Dr. Cohen is also quite correct to point out that there is variability in density and hardness even within the same species. So to the OP query as to whether there is good ebony and bad ebony, I suppose the answer has to be yes, there is. But what the characteristics are of good ebony and how a layman can tell the difference, that I have not been able to find out.

[multidon]

double post. Sorry.

[multidon]

Having had the time to do more research, it seems to me that "Gaboon ebony", "Gabon ebony", and "African ebony" are all trade names in common usage. It seems to be common in the wood trade for there to be several different names for the same wood. The term "Gaboon" may have been coined because the tree is found in both Gabon and Cameroon. It also is found in Nigeria and Zaire.

Not meaning to be argumentative Pete, truly I am not. But there are so many wood trade names floating around it is hard for me to understand why one is correct and another is not. I think the reality is that the only wood name that has any specific "real" meaning is the scientific name, genus and species. The lumber industry has confused us all to the point that we need that to know what tree we are really talking about. In the case of the wood from this particular tree it is Diospyrus crassiflora.

[Dave Cohen]

I've said it before and I don't mind saying it until I'm blue in the face. West African ebony is Gabon ebony not Gaboon ebony. It's named after the country, Gabon. It's not difficult.

Gaboon, Gabon, potayto, potahto,..., libations, craic,...what the hey do I know. Gimme some symbols and numbers, man. I can deal with those.

[Pete Jenner]

Don, as far as I can discern, it's only called Gaboon in America. You wouldn't call Brazilian rosewood "Perzilian Rosewood" if you found it also grew in Peru. Ask yourself: "If I went to Gabon and asked for some Gaboon Ebony, is it likely I would get a punch in the nose?".

I am however convinced that "Young's moduli" is in fact a misspelling of "Young's mooduli" and I shall use that term until such time as the resident scientists start calling west African ebony 'Gabon' ebony. After all, I know I get denser and stiffer when I'm in a bad mood so why shouldn't wood? It's human too isn't it?

[multidon]

Pete, I don't think wood is human, but some believe trees are inhabited by spirits. I'll bet the spirits don't really give a hoot what we call them.

Did somebody say spirits? Sounds like a good idea!

Point taken about local nomenclature. I'll bet they don't call Brazilian Cherry that in Brazil. Especially since it bears no fruit. It bears seed pods as far as I can find out.

I guess we kind of drifted off topic. Sorry about that John. As for the CA bridge, it is a well made bridge that should function as intended when properly fitted. But I don't believe it is a magic bullet. It might help, or it might not. And it is not the only well constructed bridge out there. I have always bought mandolins that sounded good with their stock bridges. Better I think than buying an instrument lacking in tone then trying to retrofit variables in the hope that something will get better.

[Pete Jenner]

Pete, I don't think wood is human

Oops ...maybe I'd better stop talking to my wood then. It would be a lot easier if it stopped answering back. Is it wrong to be attracted to a particular piece of red maple? She ....err I mean it is only a curvy little off-cut.

Pass the spirits Don.

[Stephen Perry]

QA. Consistency. Mechanical stability. The stock bridges have improved on many instruments, but not all. One of the things that used to happen to one brand was that the bridges would bend and lean towards the fingerboard. Other than QA, the CA and other good bridges offer distinctly tighter tolerances on the saddle hole fit to post and on the wheel threading. This is a good thing and I suspect makes for better performance.

I've replaced a goodly number stock bridges on some brands that I fitted earlier with better bridges and have had consistently better results.

So the view here is that the added upgrade isn't really required?

[PaulVA]

The stock bridge on my "The Loar" LS 600 cracked, and I replaced it with a Cumberland Acoustics. It did improve the tone, more volume and the trebles are noticeably stronger, so the upgrade was worthwhile but it was in this case driven by necessity. What is worth mentioning are some obvious differences in the two bridges, stock v. C.A. The CA is bigger in all dimensions except the length, and seems a lot stronger, so it's easy to see how it should be much less prone to leaning and cracking, both of which the stock bridge did.

[Folkmusician.com]

I believe I hold title to doing the most CA bridge upgrades of anyone. Aside from what I sell on new mandolins, I get a fair amount of instruments shipped in for work. Now you may think that I just can't wait to sell customers on an expensive upgrade, but in all honesty, that is not the case. It takes around 2 hours to do a really good fitting from a bridge blank. It's a lot of work! I actually have a slight cringe when we sell a mandolin with one. There goes two additional hours of my day. Granted I do enjoy the process. Anyway, I am here to tell you that there are more profitable things I can do with my time that fit bridge blanks.

So when a customer asks about upgrading, I tell them that it will make a difference. It will not be a night and day change, but it is something that is noticeable. Whether or not it is a good value depends on the the cost of the mandolin it is being fit to. As a general rule, once you get up toward $1000 it is an ok investment. While the bridge will improve a $500 mandolin, it is harder to justify the expense.

Any Kentucky lower than the master models can really use the upgrade. Once you get to the master models, the bridges are higher quality. There is still an improvement fitting a CA bridge to something like a KM-900/1000. It just isn't as dramatic as the mandolins with lower grade bridges. The Loar's, Kentucky's (below the KM-900) and Eastman's absolutely benefit from the bridge upgrade. At least as important as the bridge itself is the fitting. Slapping a CA bridge on without the detail work is not going to help much if any. It is not just about fitting the foot to the top. Can one single part make a difference? If we are talking about the bridge, then yes. Other parts, not so much.

Until you get up into the expensive instruments, the best sounding mandolins that are readily available will be something like an Eastman, LM-600 or 700 or a higher model Kentucky, with a great setup and an upgraded bridge.


Like Stephen has said in the past, much of what I have learned came from working with violins. Until I had experienced it myself, I just would't have believed how big of a factor the bridge can be on an instrument. Lightly working a violin bridge can drastically change the tone. Granted a mandolin bridge does not function as a violin bridge, but it is still a very good reference that has had a great deal of study. Ask any talented violinist and you should hear stories about dramatic changes (for better and worse) as a result of a new bridge, or bridge work on their instrument.

[Dobe]

[QUOTE=multidon;1346210]
Did somebody say spirits? Sounds like a good idea!

I'm with ya, barley based however ?

[Charles E.]

I have found that the quality of the Ebony that Steve uses is quite good and the intonation pattern is also fine. The posts and thumb wheels are much better then on a stock bridge from the imports.
I had the pleasure of doing a custom order from Steve with some African Blackwood pieces that I sent him and was VERY happy with the results. He is also just a wonderful person to do business with and hoot to talk to over the phone.

[Willie Poole]

I might as well put in my two cents...I think most people also change strings when they fir a new bridge, whether it be a CA or just making a better fit on a stock bridge, so right away they feel that the bridge gave them a better sound when it could have just been the hew strings....I bought two CA bridges in case I messed one up when fitting it, I didn`t see a bit of difference when I fitted it on a Kentucky KM-900, so I put the stock bridge back on and sold one of the CA bridges to a Café member for about 1/3 of what they cost...Now that is just what I did and some of you may get different results and how would you ever know if you never tried one? Just maybe some builders are using the CA bridges, might be a selling point if they would say what they are using, I see them tell about what wood the top, back and sides are made of so why not the bridge also? On an `50s F-12 that I owned the rosewood bridge sounded better than an ebony one did, but that is just one mandolin and also the sound that I like which may not be what the OP likes...AGAIN, TRY ONE AND SEE....You are the person that has to like it...

Willie

[Stephen Perry]

I'm with Robert above. The bridge makes such a difference. Well, everything does. I'm so tempted to make some mandolins so I can experiment with grounds etc from the violin world.

I have a big bag of cracked bridges and the like from cheap mandolins, and the density of the wood is all over the place. The design is also often unpleasant. On the other hand, I often get violins in unset because I know I'll be unhappy with the setup. I'm one of those people who hand splits out soundposts and so on.

The filtering aspect of bridges is what really interests me. In the not so hot bridges there's much less consistent filtering. The design I'm working on allows more consistent and easier manipulation of filtering. In the meantime, Steve' are so consistent that I will continue to use them.

[Steevarino]

Stephen, as you know, I am anxious to see what your clever mind comes up with in terms of your new bridge design. Be sure to keep us/me posted!

Willie, sorry it didn't work out! In almost all cases, we offer a full refund if a customer is unhappy with the bridge we sent them. Even if it has been altered to some degree, we still offer a generous partial refund, as we can use them on repair jobs, etc. So, if you are in the small camp of unhappy customers, call or e-mail us first!

Charlie, I ended up with quite a few bridges from those small scraps of Aftrican Ebony you sent me. Below is a picture of one that I kept for myself. I liked these two pieces, as they retained a bit of the yellowish sap-wood. I fit it to my Cliff Sargent F-5, and it really woke this mandolin up!

[John Adrihan]

Since I am the OP I will disclose that I have a very good sounding km1000 that Is my spare, and actually gets a lot of use because of of how good it sounds. When I bought it the store said no need to replace the bridge. Well around 6 mos or so of playing I ordered a CA bridge. I actually bought a high boy, with the theory that I like my action real high and with the extra height of the saddle maybe I would not have raise it on the posts so much. So it came and I started to fit it and during the fitting process I sanded it enough to lose the gap of the arch. So I re- arched it myself. To make along story short, during this process at one point at band practice the guitar player said "what ever you are doing stop, because it sounds great" anyways the reason for my post is, I am really happy with the CA bridge but don't understand why it made the mandolin better. The original bridge seemed to be fitted just as good or better. Is it because it is lighter?

[Andrew B. Carlson]

Pretty sure they're heavier actually. More wood in the CA than the KM-1000 bridges. Made a difference on my KM-1000. I read from one guy in here, maybe Tom, that more mass calms down the trebles on those Kentucky's. He also put a CA on his KM-1000.