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We've all seen that some bridge bases are level with (contact) the top all the way across, while some have two "feet." Even within the same brand, both can be found. Is there an advantage to either?
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12-12-2016 02:02 PM
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you'd think full contact would be better.
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I prefer full contact.
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Yeah you would think. But Gibson, for example, makes both styles.
Originally Posted by wintermoon
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two feet are easier to fit Originally Posted by Woody Sound
there is no audible difference IMO
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I'm not sure that I would automatically think that full contact bridge bases would be superior. Archtop luthiery is an outgrowth of violin/cello instrument making. No Strad, Guarneri, Amati, etc., violin would ever feature a full base bridge, no? No Czech carved bass would have a full-foot bridge.
The best guitars I have owned have featured two-feet bridges.
YET, who can knock the sound of the great instruments that Jimmy D'Aquisto made which feature solid bass bridges?
It's a puzzle.
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I read somewhere that the reason for the holes in a violin bridge is so that there is no direct path to the top from all four strings. Kinda odd, you would thing you'd WANT a direct path. But I know very little about how a violin works. Originally Posted by Greentone
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Agreed Originally Posted by fws6
I agree that the distinction between bases, alone, is marginal at most. Full-contact has always seemed a bit darker and a bit louder to me, but I'm pretty gullible on stuff like that. Originally Posted by fws6
On the other hand, going from metal top to wood, going from 'in-the-air' to 'pressed all the way down' and going from wheels to no wheels each yields a difference.
Only superficially. The difference between bowed and plucked tone production is monumental, both with respect to volume and timbre. Construction-wise: Originally Posted by Greentone
. The angles are all way steeper on violin-family instruments
. There's one tone bar
. It's never an 'x'
. There's a sound post
. The f-holes are different sizes and in different places
So I can only guess that the plate mechanics are way different.
Ohhhhhh yeah Originally Posted by Greentone
Last edited by Sam Sherry; 12-12-2016 at 05:47 PM.
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not saying one is better than the other, just some observations:
Gibson switched to single foot in the mid 30s and stayed that way until tune-o-matics were introduced on electrics.
the Johnny Smith always had a single ebony foot, likely specified by Smith.
D'Angelico switched around the same time as Gibson and never changed, same w/D'Aquisto who started making huge bridges at one point.
most modern luthiers use single foot.
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this is counter-intuitive... but if the amount of vibration transferred to the bridge from the strings is equal in each case, maybe the full-base bridge dissipates more of it or alters the vibrations more because the same amount of energy passes through a larger, dense medium. But with feet, all that energy is sent through a smaller channel..
... on the other hand, maybe not.
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From a technical point of view one could state that the larger the lower contact surface of the bridge base is, the lower the surface pressure on the top will be at that point. (surface pressure = force divided by the contact surface). Thin carved archtop tops sometimes are vulnerable for deformation (sinking of the top). Given the same bridge base footprint, a full base is better than two feet.
From a tonal point of view, it could be way different.
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From what I have seen, the Gibson bridges form the golden era of archtops had a single contact surface. From what I have seen recently is cheap two-foot bridges that splay apart under tension.
I try to use single-foot bridges and avoid the others.
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Last month I decided to take a huge risk and I refit my solid base bridge on my Heritage Gretsch. I had no idea what to expect but I was as diligent as I could be. Lo and behold, the dang thing got noticeably louder. It didn't change the tone much if at all but it definitely got louder. And no my ears didn't pop.
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Full acoustic, bridge fitting is probably very important. For electric, I can't tell much difference, before and after a good fitting. The violin people go ape over this stuff...
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Keep in mind that the guitar bridge is the strongest (external) brace or tonebar on the soundboard, thus its entire construction (the base and saddle) will influence the plate resonances.
The stiffness and, above all, the weight of a bridge are really important factors. A bridge with an incision on the base, the more a bridge with two feet, is usually lighter and more flexible than a full contact bridge.
On most archtop guitars that are made according to the construction principle "lighter or thinner, i.e. not much graduated top + heavy (internal and external) tonebars + built-in humbucker(s)", the bridge construction may be less important tonewise. These guitars are, firstly, optimized for easier and more costcutting production and, secondly, get most of their tone potential from the pickups, thus helping to get a relatively even and consistent electric tone out from different examples. Not a bad idea, but I recommend to test also the tone, response and acoustic eveness that guitars with a thicker top of 6 - 8mm - plus the necessary recurve - can deliver. A revelation for some in the past and present...
Please note also that on electric archtop guitars the weight relation of the carved plates to the comparably light tonebars is much less meaningful than on flattop guitars that often combine feather-light plates with more and relatively heavier bracing.
Another difference of the bridge construction is its function as an impedance transformer, though again, this involves both the base and the saddle.
>> I read somewhere that the reason for the holes in a violin bridge is so that there is no direct path to the top from all four strings. Kinda odd, you would thing you'd WANT a direct path. But I know very little about how a violin works. <<
If a violin or cello bridge is scientifically constructed and is the right height according to the width, and the incisions are placed right, and the strings spaced correctly, it will be the same distance from any string to either foot of the bridge. At no place the vibrations from the string pass directly to the foot of the bridge. Since almost five centuries violin makers think regulating this would be important in overcoming any uneveness in the strings or instrument. By breaking up the vibrations from the string before they reach the top of the violin, a much more even compass on all four strings would be sure to occur.
>> The difference between bowed and plucked tone production is monumental, both with respect to volume and timbre. Construction-wise:
. The angles are all way steeper on violin-family instruments
. There's one tone bar
. It's never an 'x'
. There's a sound post
. The f-holes are different sizes and in different places
So I can only guess that the plate mechanics are way different. <<
I know there are some heavy violin and guitar separators here around and in all guitar milieux. But if it comes to archtop guitars, they are off the track. Sure, some differences between the construction of bowed and plucked stringed instruments exist, but much less than most guitar players would ever think of! Just in a few words, the most striking differences are:
1. Violin/cellos are usually played - with a bow. Hence, these instruments can get more power input, endless 'sustain' or rapid stop/decay. The bow handling is also responsible why violins/cellos must have the slightly stretched body (narrower, but longer), compared to guitars.
2. The specific bass bar and soundpost assembly of violins/cellos helps to prevent a potential phase cancelation of both top halves, the bass and the treble side, i.e., a power and volume issue. The old guys worked really hard to enable the violin/cello players to get heard well by the audience in a larger venue - even as a solist. Try the same with your best archtop guitar, unamplified, of course... This concept is still waiting to be tested in the archtop guitar world - well, some did already...
3. The frets make for one of the biggest differences.
The rest are peanuts, like the longer neck on the guitar (which makes it the more a real tuning fork: watch it, you guitar makers!) or the tuners (who thinks he/she would really need a 18:1 gear ratio?). By now, the best archtop guitar makers were trained violin makers or former students of trained violin makers. IMHO, there's no way around that on an average the violin makers are more trained, sophisticated and experienced in delicate repairs and restoration work than guitar makers. Exceptions prove the rule. Men like Ken Parker frankly admit that they've learnt so many from violin making techniques, and are still learning.
. The steeper break-over angle on violin-family instruments is mostly due to the handling of the (long) bow. The same is for the necessary 'C-bouts' at the waist. Internally, violins/cellos show the guitar's 'figure-of-eight' body shape. And some German vintage acoustic archtops like Arnold Hoyers or Rogers imitated the steeper break-over angle/higher bridge/steeper neck angle - mostly with success! It's also nice to have sufficient clearance for using a full-size floating humbucker - some players like this constellation.
. E. Stromberg used a single (diagonal) tonebar on some models, I guess, with success. German makers like H. Todt or H. Wurlitzer or G. Graubner, and others, who made 'custom' archtops in the 1950/60s, loved the single violin tonebar. Just because only a few happy guitarists know how these guitars sound and feel, doesn't mean these must be inferior axes.
. Neither the violin/cello makers nor the German vintage archtop guitar makers use(d) X-bars, for simple constructional-mechanical reasons. You can also ask the modern physicists and engineers how to get the best stiffness/mass relation out of an archtop body, by longitudinal or by X-bracing. Well, I know, the tone perception is nothing but subjective... that's fine - paradise is a personal thing! However, the former groups experimented like crazy from the 'no tonebar concept' to 'two or more tonebars' in different sizes and places under the top. They found the better (though more time-consuming) way to control the necessary flexibility of the soundboard was the proper wood selection, the plate graduation, the recurve, the tonebar shaping and the sound hole opening/placement.
. If a good luthier would put proper soundposts correctly into our favorite axes, I am convinced that many of us wouldn't even notice the difference. The uncrowned former GDR master Heinz Seifert used soundposts in some of his late (1980/90s) guitars, often in the more electric archtops, probably to eliminate feedback issues. Acoustically, these (often slightly slimmer) guitars are as loud as any electric L-5. Of course, tonewise these are not identical. Many of the German vintage guitars were designed a priori to sound less 'bassy' or muddy, but shine more with well defined, even mids and a clear-voiced, strong treble range - that is acoustically again.
. Comments on the varying sizes and placements of the sound holes, and their effects on the sound of archtops would fill half a book. The 1940s Epis, for example, and newer guitars like those by Theo Scharpach and Dan Koentopp, and some others more, successfully more or less sport the violin/cello-shaped sound holes in comparable placements.Last edited by Ol' Fret; 12-12-2016 at 10:28 PM.
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There can be a difference in sound between the bridge types, but IMO the difference is unpredictable. The top of each instrument is different, and there are different designs - laminate, carved, pressed, etc. Smaller feet do mean more pressure per square inch (or square cm, whatever the unit of measurement) but whether that's good or bad is uncertain. Considering the cost of bridges, it would make sense to try both and see which is preferable on the guitar in question. If it's a full-contact bridge base, then it needs to be properly fitted.
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Yes. On purpose. I think it originally was a Gibson effort to make a "self-adjusting" bridge which did not need time-consuming custom fitting to achieve full, or fuller, contact with the top. Originally Posted by icr
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This is certainly the belt and braces approach to bridge fitting on violins and wouldn't work on many, especially old instruments. The reason is hand carved creations aren't necessarily perfectly symmetrical and neck alignment can vary. Originally Posted by icr
Full acoustic, bridge fitting is probably very important. For electric, I can't tell much difference, before and after a good fitting. The violin people go ape over this stuff...
Very small bridge movements can make large differences in tone on violins, the correct thing to do is start at the normalized location and adjust for tone. The same can be said of soundposts and their fitting.
For guitars this can be true too but they are much less standardized than violins, a thin top should have a wider base to spread the load, a thicker top can be louder with smaller feet for more point loading but to find what works best for a particular instrument takes some trials.
I have experimented with soundposts in guitars but found them less effective than on violins. This is in part due to the differences between a bowed sound generation with limitless sustain and a plucked string. For a experiment pluck a note on a violin and you won't hear a ringing note as the top isn't freely vibrating but a duller plunk. Add a sustained bow and that soundpost is helping create a vocal vowel like resonance. For a guitar a soundpost might be better for reducing amplified feedback resonance but with the differences in bracing and construction finding the best location, if any, will take lots of trial and effort.
F holes certainly matter but again there isn't a standard in bracing and construction on the bodies to go by. Looking at the combinations that have given good results is the ground floor here. When I put together my 58 ES 125 it went for years without a pickup installed as a round the house practice box. I remember being disappointed that covering the P 90 pickup hole reduced the volume so much. I always thought a small oval hole with the stock f holes would be a nice combination for this body style for acoustic sound. A E-125 /Howard Roberts combo seemed fun.
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I can say this, as a hacker fitting a solid base to a top is a PITA, and the only reason I have done it at all is I have had a bridge slip on one of my Epiphones, and I figured the extra surface contact from the solid bridge base would hold it in place.
Curing the bridge slippage worked and I never noticed that the tone or acoustic volume changed.
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To be sure this is pretty subtle stuff, if your tone is coming from a magnetic pickup acoustic nuances can be harder to detect.
Another way of looking at the uncoupled back of a guitar is it is acting like a sound reflector instead of another vibrating plate like on a violin. A violin has both top and back largely unobstructed so they can both vibrate generating increased tone and volume. A guitar back is always dampened by contact with the player, what would that deadened plate do to the top if connected towards the center? Ovations are a great example of a parabolic sound reflector shaped to get the sound out of the box. Because the back isn't contributing much of the tone it can be (gasp) fiberglass.
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2 legs? how about very skinny ones
Of course application for solid body like a Les Paul where sustain is more desirable than top vibration might explain their use
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The bridge I have been using most recently is one I make myself. I like a narrower base of 7/16" rather than the standard 5/8" base width of most archtop bridges. I like two feet with only a small gap between them. The narrow width is lighter yet still very strong.
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The two foot violin type bridge base has an undesirable trait of spreading the bridge posts more as the arch of the top changes. That makes adjusting the bridgd hard. A TOM could be REAL hard to adjust but wood ones can be reamed a bit to accomodate the Y effect of the posts from the base following the curve of the top.
If I weren't so lazy, I'd fit one to all my archtops.
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I know the type of two foot bridge you are describing. They are poorly designed in my opinion. The center of the bridge flexes way too much. It makes them easier to fit but they lack stiffness where it is needed most. The type of two foot bridge I prefer is like the bridge often found on mandolins. They have a thick center section and the feet are close together. The bridge I have been making most recently is a bit like a mandolin bridge scaled up slightly for the guitar. I have done some crude testing and I have had good results with this type of bridge. I have always been impressed by the mandolin and how much volume they can produce for their size. The mandolin bridge has a tiny footprint and yet it must carry a much greater load than a guitar. The angles are steeper and the sting tension is higher on a mandolin than on a guitar. My thinking is, if that tiny bridge can carry all that weight then surely a slightly smaller bridge will be safe for a guitar. So far I do like these smaller bridges. Originally Posted by GNAPPI
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I laugh at your puny archtop bridges.
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