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Pin bridge vs tailpiece
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Author:  YiFo [ Wed Aug 26, 2015 11:15 pm ]
Post subject:  Pin bridge vs tailpiece
Hi,

I am currently building a flattop version of a Gibson style O guitar (which was originally a carved archtop guitar). I am doing my own interpretation of it, but am currently in doubt about what bridge type would be better....

Soundwise, what benefits are there using a regular pin bridgeor a tailpiece bridge? I would love to do a tailpiece since I have never done that before, but somehow I feel that a tailpiece bridge would decrease volume....not sure though.

I can't find any info on the difference in sound between a floating tailpiece bridge and a glued on pin bridge on a flat top.

So if anyone has any info on that I would be really grateful.

Thanks,

Ivo
Author:  meddlingfool [ Thu Aug 27, 2015 12:35 am ]
Post subject:  Re: Pin bridge vs tailpiece
Hi Ivo,

I don't have much to tell you, other than that a tailpiece bridge and a pinned (or unpinned bridge) make the top behave very differently.

If you want to have your eyes opened about how guitars do what they do, I recommend to you the Gore/Gillet books.

Worth every cent.
Author:  jfmckenna [ Thu Aug 27, 2015 7:50 am ]
Post subject:  Re: Pin bridge vs tailpiece
I would suggest that a guitar that is built and braced for a pinned bridge would probably loose volume if you instead put a tail piece on it but when you hear how loud Selmer guitars that have a tail piece for example then it's not correct to assume that a guitar with a tail piece is not loud.
Author:  Ruby50 [ Thu Aug 27, 2015 8:15 am ]
Post subject:  Re: Pin bridge vs tailpiece
jfmckenna

What is the bracing like inside those Selmer's? Does it differ at the bridge area? I know i have read about switching some older tailpiece guitars to a pin bridge and how the sound "improved", but does the inside bracing have to change when you do that?

Ed
Author:  Bobby M [ Thu Aug 27, 2015 8:35 am ]
Post subject:  Re: Pin bridge vs tailpiece
Ed,

Here is a link to a luthier who has worked Selmer nr430 and nr657 and a Maccaferri nr423. The 430 was unique in that it had only 3 top support braces while most of his work utilized 5 parallel braces. His conclusion was this was a transition guitar built when Maccaferri left the factory.

http://eimersguitars.com/learning-from-selmer/

and another link describing bracing: http://lehmannstrings.com/Articles/selmer.htm

and a link to some plans: http://www.rfcharle.com/HTML/PlanSelmerA.html

Hope this helps.
Author:  George L [ Thu Aug 27, 2015 9:04 am ]
Post subject:  Re: Pin bridge vs tailpiece
I'm not Ed, but that's good stuff, Bobby. Thanks for sharing those links.
Author:  Alan Carruth [ Thu Aug 27, 2015 4:25 pm ]
Post subject:  Re: Pin bridge vs tailpiece
The main difference in the way the strings drive the top between a pinned bridge and a tailpiece is that the tailpiece takes up the twice-per-cycle tension change. On a pinned bridge this torques the top, and adds some energy in the second partial of the notes. With a tailpiece you don't get that.

Note that the actual POWER produced is not noticeably different. For one thing, the 'tension' signal is only about 1/7 as powerful, on average, as the up and down 'transverse' signal. The transverse signal also drives the top like a loudspeaker cone, which is much more effective at producing sound than the torquewise motion of the tension signal. Aside from the 'phase cancellation' from one part of the top moving up while the other moves down from the bridge torque, we built tops to resist that sort of motion, so a given force produces lots less of it. You might also note that a string only has so much power to put out, so if it comes out one way, it's not there to come out some other way. In the end, what you can get with a tailpiece is a somewhat different 'recipe' of sound, but it's not all that much different. Most of the differences in timbre between archtops and flat tops are from other things, like the (generally) higher pitches of the main resonances on archtops.

Orville Gibson did build his archtops with pin bridges, from what I've seen. Given the difficulty of torquing the bridge on an arched top, I suspect that switching to a tailpiece would not change the sound much. It must have been a pain to fit those bridges...

I've built archtop Classical guitars with tailpieces, and if you do it right they don't sound all that much different from flat top ones.
Author:  YiFo [ Fri Aug 28, 2015 12:21 am ]
Post subject:  Re: Pin bridge vs tailpiece
Thanks for the help. Are there any specific things I should keep in mind while bracing it? Like I said, it's not an archtop I'm building, but a flattop....I am x-bracing it, but not sure whether I should change the setup. I started withe the X and want to place the bottom 'legs' so that the bridge will rest on both of them. I think this will give it support, but are there specific bracing patterns I could/should think of?
Author:  Mark Mc [ Fri Aug 28, 2015 5:16 am ]
Post subject:  Re: Pin bridge vs tailpiece
Most of the early tailpiece models like the Stellas and all of the Selmers have ladder bracing, not X. That doesn't mean that you can't put X-bracing and a tailpiece together - it has been done and would work fine, just different. It depends on whether you are trying to emulate a particular historical model or put your own combination together.

One important difference is that the tailpiece design means that there is predominantly downward force on the bridge while a pinned bridge has a rotational force. This has implications for what you need the top bracing to be doing.
Mark
Author:  kencierp [ Fri Aug 28, 2015 7:23 am ]
Post subject:  Re: Pin bridge vs tailpiece
Conceptually its seems that the tail pieces are supposed to be used (or normally used) on instruments with movable bridges and most importantly in concert with highly arched crush resistant soundboards like the violin family of instruments. Even the Selmer's have a lengthwise "folded" sound board to create the arching resistance. Batson does something a little different by threading the strings through the bridge rather than running them straight on top of the saddle --- to me those guitars still have the "F" hole jazz sound and lack volume. I've heard a few 12 string guitars with tail pieces that sound OK -- very stringy

The guitar scientist here certainly know better, but I would think that having the strings pull up on the sound board would tend to result is a more responsive guitar as opposed to one that has a sound board braced/designed to prevent the string tension from caving in the sound-board. Also depending on the tail piece to transfer string energy seems less efficient overall.
Author:  Alan Carruth [ Fri Aug 28, 2015 11:30 am ]
Post subject:  Re: Pin bridge vs tailpiece
Somehow you need to get some break angle at the saddle so the string will know how long it is. Normally the strings break downward, toward the soundboard, and this puts a down force on the saddle. On a pinned or tied bridge that's countered by an upward force at the pin holes or tie block That creates a static torque on the bridge, and the bracing is designed to resist that. With a tailpiece all you've got is the down force, and it's hard to make a responsive flat top that will resist that for very long. Note that the actual break angle need not be too large: six degrees is just enough, and beyond that you don't get any more sound from the strings, despite the legends to the contrary. Still, with 150# or so of string tension, that six degrees of break puts a download on the top of about 15#, which can distort the top quite a bit over time. With a more 'normal' 30 degrees or so of break that rises to 75#: fergitit.

One manufacturer has solved the problem by breaking the strings sideways, to pins around the rim of the top behind the bridge. It probably works OK, since the strings don't know which way they've been bent. Resophonics use tight string notches in the bridge to lock the strings in place without the need for too much down force, which that thin aluminum pie plate won't stand up to. Pianos thread the strings back and forth between several pins that are in a line to get the same effect: with tons of total string tension they sure can't use a downward break to stop the strings at the bridge!

The other normal options are to either 'crank' the top as is done on the Selmers, and Neapolitan mandolins, or arch the top as is done on viols, fiddles, and archtop guitars. Cranking the top essentially splits the soundboard into two vibrating parts; not only does the break add a lot of crosswise stiffness, but it's usually backed up with a pretty substantial brace. Even then they collapse, as you can see on many old mandos. On violins and such the arching is reinforced with a pretty good sized bassbar, and also there's a sound post that runs from the top at the treble end of the bridge to the back. It's interesting that the term for the sound post in all the Romance languages is 'ame', or 'soul', and lots of nonsense has been written about that. One person tracked the usage back and found that, at the time the thing was invented, they used that term to refer to the stick you used to prop open a window: in both cases it's out of sight (in the fiddle or behind the curtains) but keeps things alive. A sound post in an archtop guitar tends to be a great way to kill the tone: it works on fiddles in cahoots with the tall bridge because of the way the bow drives the strings. On archtop guitars there's a real premium on getting the arching right so that you get a decent sound without a top that collapses over time.

In short, there are good reasons why flat top with tail pieces are not the norm. It's mostly been an expedient used on things like the Stella 12s, to make an affordable guitar that will hold up for a while, but they're not generally built for the ages.
Author:  jfmckenna [ Fri Aug 28, 2015 12:07 pm ]
Post subject:  Re: Pin bridge vs tailpiece
Ruby50 wrote:
jfmckenna

What is the bracing like inside those Selmer's? Does it differ at the bridge area? I know i have read about switching some older tailpiece guitars to a pin bridge and how the sound "improved", but does the inside bracing have to change when you do that?

Ed


For sound purposes perhaps not but for structural purposes probably. The Selmer guitar has arched braces to take the downward force of the strings while the pinned bridge has the X-Brace to withstand the torque. I've only build Selmers with 5 braces but have considered going to 4 or lightening up the 5 considerably. 3 braces seems way too little and I think the article Bobby pointed out makes that clear. I also build them with the Pliage which gives more of a string angle to the tail piece and may have something to do with the loudness. It seems to me that Selmers are braced heavily. I have a long long way to go before I understand them but they are really fun guitars.
Author:  YiFo [ Sat Aug 29, 2015 2:59 am ]
Post subject:  Re: Pin bridge vs tailpiece
Well after some reading, I've decided to go with a 'double X" bracing to support the top considering the downward force...
The top will have a 17ft radius to give it some extra dome.

Hope this will give the it enough strength and also some 'freedom' to resonate. Will have to figure out the rest of the bracing pattern still, so any suggestions are welcome! Keep the info coming Thanks!!
Author:  Freeman [ Sun Aug 30, 2015 8:39 pm ]
Post subject:  Re: Pin bridge vs tailpiece
Ivo, a couple of thoughts. I've built a ladder braced 12 string (Stella clone) and kept the option open. I put a pyramid style bridge on in (glued on, not floating) but didn't drill the pin holes. I mounted a tailpiece and strung it up, knowing that if I didn't like it I could remove the tailpiece and drill pin holes. FWIW, I kept the tailpiece.

Image

Second, I had a request to build "an acoustic guitar that looks like an ES-175" (which is a pressed top Gibson normally played thru pickups). I made a thin spruce top and put a little more dome into it than normal (about 15 foot) and braced it with a simple X mostly to hold that dome.

Image

I did put a bridge plate in it, don't know if that was necessary or not. They guitar has a floating archtop style bridge and tailpiece. Everyone who has heard it says it sounds like an archtop (duh)

Image

(don't ask about the inlays - customer requests are, well, customer requests....)

Alan has mentioned a couple of the structural considerations. A floating bridge and tailpiece applies a component of string tension more or less perpendicular to the top. This works pretty well with either ladder braced (and my understanding is that SelMacs are essentially ladder braced) or X braced like some archtops. On the other hand a pinned bridge applies a lot of rotational torque at the bridge - I've always understood that strength of the X is in the weakest part of the top (between the bridge and soundhole) were that torque is the most. So my humble advice would be to use X bracing if you want to pin the bridge, but a tailpiece could be used on most any bracing.

Last comment, Todd Cambio at Fraulini Guitars builds mostly ladder braced guitars based on the traditional old designs but he uses both pins and tailpieces. I had a discussion with Todd when I was building my 12 string and he said that to his ears the tailpiece versions had a less complex sound - more of the fundimentals and less overtones. There are some sound clips at this site - you might be able to learn something from them.
Author:  jfmckenna [ Mon Aug 31, 2015 9:27 am ]
Post subject:  Re: Pin bridge vs tailpiece
Hey freeman the binding on the 12-string looks cool. I also really like the shape of the lower bout. Is that an exact clone? It looks different to me. do you happen to have a full image?
Author:  Freeman [ Mon Aug 31, 2015 11:31 am ]
Post subject:  Re: Pin bridge vs tailpiece
jfmckenna wrote:
Hey freeman the binding on the 12-string looks cool. I also really like the shape of the lower bout. Is that an exact clone? It looks different to me. do you happen to have a full image?


No, its not a direct copy - it was based loosely on the hand drawn plans of Stefan Grossman's Stella for bracing and all, but the body size fits my 000 mold. The binding and rosette is from LMI, adi spruce over mahogany, scale is 26.5, strung with cables and usually tuned C to C. I tried to keep it simple in keeping with the Stella theme but it is not an exact clone. Btw, building odd ball guitars like this means you have to buy expensive custom cases - oh well..

Image

sorry about the thread drift
Author:  Greg B [ Mon Aug 31, 2015 1:24 pm ]
Post subject:  Re: Pin bridge vs tailpiece
People used to commonly convert old trapeze bridge flat tops to pin bridges. I don't think this is done anymore....

Anyway, I've heard a few of these both before and after on the same instrument. Plus, i've made a couple experimenter mules that have had both types. Yes, the sound of a trapeze bridge is more fundamental with less overtones. But that's not to say a trapeze type cannot sound rich and musical as well. More importantly, IME a pin bridge will have a bit more bass, so best to compensate on a trapeze type by making the top thinner, or the bridge heavy, etc.

The difference in string motion has been well covered many times before. Suffice it to say, it differs a bit.

IMO a double X isn't necessary, since the bridge is not trying to rotate. The main issue is maintaining a slight arch. A simple transverse tone bar would be better IMO. BTW, I'd go for more like 12-15' radius rather than 17'. It's going to collapse a bit in practice.

There's one more thing about trapeze bridges that nobody talks about: it is much harder to break strings when hard strumming. Probably that's part of what made archtops useful for jazz band rhythm sections.
Author:  Alan Carruth [ Mon Aug 31, 2015 1:44 pm ]
Post subject:  Re: Pin bridge vs tailpiece
Freeman wrote:
" Everyone who has heard it says it sounds like an archtop (duh)"

With that layout and F-holes, I should thing so.

"Btw, building odd ball guitars like this means you have to buy expensive custom cases - oh well.."

OH yeah. I have a fairly strong rule about not building guitars I can't buy a case for, but every once in a while.... I just delivered a harp guitar that folds up and goes into a box that will fit in the airline's overhead. The case was almost as much work as a standard guitar, and the instrument.... It will be pleasant to get back to something more normal.

Greg B wrote:
"The difference in string motion has been well covered many times before. Suffice it to say, it differs a bit."

Actually, the way the strings move is the same, but the forces transmitted to the top via the bridge are a bit different.
Author:  YiFo [ Tue Sep 01, 2015 8:45 am ]
Post subject:  Re: Pin bridge vs tailpiece
Well, progress so far....it's going to be a 12fret, with a tailpiece (a very short one). The bridge will rest on the 2 xes. We'll just have to wait and see what happens when it's finished....hope it won't collapse ;).

I'm also thinking of building a virzi tone producer in it (just as an experiment) and try to make sure it's detachable....maybe I'll do something with magnets....anyone with any experience?
Author:  YiFo [ Sat Jan 16, 2016 2:12 am ]
Post subject:  Re: Pin bridge vs tailpiece
Well, I just finished it. It's a great resonant sound, I decided to go for a four x-bracing pattern, the bridge rests on the double X. I've added a" Virzi-tone producer like" plate under the top which really makes the guitar sound like it has some kind of built-in amp with a nice reverb. I'll post a video of it as soon as I find someone who can actually make her sing (I really stink at playing guitar :cry: ).

Here's the specs: Gibson style O Artist. Black Walnut back and sides, spruce top, maple neck and ebony fingerboard 12-fret
Author:  TimAllen [ Sun Jan 17, 2016 2:45 am ]
Post subject:  Re: Pin bridge vs tailpiece
Wow--that's amazing! Congratulations!
Author:  gepatino [ Mon Aug 22, 2016 9:53 am ]
Post subject:  Re: Pin bridge vs tailpiece
Apprentice here.

After having almost finished my first charango, and almost 50% my first ukelele, I'm thinking about the next one: a classical guitar.

I was thinking in using a tailpiece in a classical (nylon strings) and this thread was very usefull. Now, how much down pressure would the nylon strings apply to the top? Would the arched top still be neccesary?

Thanks to all of you.
Author:  Alan Carruth [ Mon Aug 22, 2016 2:40 pm ]
Post subject:  Re: Pin bridge vs tailpiece
I've seen Classicals with a tailpiece that used the normal tieblock bridge too. The strings go over the saddle, through the holes in the tieblock, and then to a tailpiece that takes up the tension. This gives the proper break angle over the saddle, at the cost of having more or less the normal torque on the bridge, but it does reduce or eliminate the shear load on the bridge glue line. Every once in a while the idea gets re-invented, but it goes back at least 50 years, and probably long before that.

Any time you have a downward force on the bridge you need to brace (or arch) the top accordingly. Both the tension and down force will be less on a Classical than a steel string, but they will be in the same proportion to each other. Classicals normally use a thinner top than steel strings, since the tension is lower, so a Classical with a tailpiece bridge would be just as likely to collapse as a steel string unless it's done right.
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