Official Luthiers Forum!

Hi Folks,

A wannabee here with a ( possibly) dumb question.

Why is it Tailpieces are used only on Archtops?. The obvious exception being Batsonhttp://batsonguitars.com/

It obviously works for them so I'm perplexed why such an elegant solution is not more widely used.
I think this is going to be glaringly obvious but thought I would ask anyway.

Cheers

The sound generating mechanisms of flattop and archtop instruments are generally different for one thing. While some flat tops have been made with a tail piece, understanding how the motion of the bridges can differ is key to understanding how instruments make sound and impart energy to the sound board of the instrument, etc.

I think, in a nut shell, and probably oversimplifying, the bridge of an archtop is supposed to move up and down, vertically in a plane normal to the plane of the top. A flattop bridge is supposed to rock about an axis oriented along the longitudinal length of the bridge.

More qualified members hopefully will chime in here.

I couldn't tell you why but years ago I tried it and I never liked it. In fact I just re-topped this instrument finally after 10 years of wishing I'd never done it

I think that it just doesn't impart the right energies to a flat top to get it vibrating.

Hi,
There is no right and wrong when it comes to sound.
I am in the process of building a Stella 12 string reproduction with a tailpiece.
It all depends on what type ofsound you are after.
I am building it with a tailpiece because I am trying to recreate the sound of a particular instrument ,played by particular players (Leadbelly and Blind Willie McTell).
Oddly enough Stella made both versions of those guitars-with and without tailpieces.
I hope this helps.
Brad

Welcome to the OLF Steve!

Check out Howard Klepper's site - I think that one of his favorite guitars that he has built is an acoustic with a tail piece. I don't want to call it a flat top because it is not flat and it's not an archtop in the traditional sense either.

Hi Steve.

As Brad mentioned, there is not right or wrong when it comes to sound, at least from a general perspective.

That said, there are few things to consider when thinking about a tailpiece on a flattop.

- With a standard pin bridge (or pinless for that matter...), the strings are held in place at the bridge level itself, thus inducing more energy to be transfered to the top, allowing it to vibrate more. A tailpiece allows for part of the string vibration to be absorbed by the tailblock section of the body, which does not generate sound. So this implies more volume when using a standard bridge.

- Most flattop bracing paterns are design to sustain the torque and twist that a standard bridge induces on the top. When using a talpiece, as mention before most of the string tension itself is supported by the tailblock section of the body, thus leaving only a 'pressing down' force on the bridge are. All this to say that if the bracing patern of your tailblock flattop is the same as we are used to see with a standard bridge flattop, than you will have a seriously overbraced guitar. Bracing it differently, more lightly (such as a Selmer is braced for example) is going to be necessary for a decent volume to come out of it. But that creates another problem (see next point...)

- Since, as it is mentioned above, a tailpiece bridge mostly pushes down on the top of a guitar, one should expect a tailpiece flattop to eventually cave in after a couple of years, especially if it is lightly braced to allow the top to vibrate more. A standard bridge flattop will twist after time, inducing a belly at the back and caving in in front, but the bridge itself will more less stay at the same high. On archedtop guitars, such as all violin types instruments that also use tailpieces, the arch itself prevents the caving in of the top.

So the conclusion to this is that arched top are built to support the pressure of the bridge but they will never get the volume of flattop.

Now take this for what it's worth; it's what I believe more than what I know. But as you will come to learn yourself, most of guitar making science is this way!

_________________
Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

Then again, if you twist that question around, why don't archtops have a string-through bridge? Has anyone tried that? Would it increase volume, but lose something else? Just curious?
dave

Steve,

Some folks are making flattops with tailpieces. As was mentioned, depending on the sound you're after, a regular archtop bridge with a shallow break angle over the saddle will transfer less of the strings energy to the top, so will not sound like a "normal" pinned/pinless bridge. From my understanding a pinned/pinless ("stop") bridge primarily transfers energy while rocking the bridge longitudinally (Siminoff), and a typical archtop bridge with a tailpiece creates more of a pumping motion on the top.

I asked that same question a while ago, but wanted the "bite" or attack of strings on a stop bridge, using a tailpiece. I figured it was primarily the string break angle over the saddle that would accomplish it. I found that it does indeed sound like a stop bridge.


Dennis

_________________
Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

Thanks for the answers guys.
I did suspect the break angle over the bridge may have some bearing on how vibration was transferred to the top but Dennis's solution looks to address that and still allow the top bracing to be reduced a little.

I'm still at the planning stage for my first build and am finding the whole thing fascinating.


Thanks again

Alain,
I respectfully disagree with your statement "one should expect tailpiece flattop to eventually cave in after a couple of years".
I think this a pretty cavalier statement There are several reputable,"high end" builders who are making this exact type of guitar. They are offering there usual warranty as far as I know,so I think they have quite a bit of faith in this particular construction!
As far as the sound of these instruments goes-Yos atated "they will never get the volume of a flattop" -Try telling that to a Leadbelly or Blind willie Mctell fan. A bunch of the old blues guys who used these guitars werestreet musicians who needed to be heard above the din of other street sounds. They picked these guitars for a reason.
It is true that most of these type of guitars are not arond 70 tears later. Some of the reasons are that they were cheaply built guitars and they were cheap guitars,so unlike more expensive ones were not worth fixing at the time.
Also the statement taht violins " the arch itself prevents the caving in of the top".
Over time the arch does "cave in" on all types of arched instruments including violins.A common job is to "re-arch old instruments.

It is an archtop in the traditional sense, with an oval hole (which actually predates F-holes in guitars).

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Hi Steve,

I have to agree with Brad because I have experienced this problem personally. I Have a 1967 B 45 Gibson 12 string with a tailpiece type bridge and over time all the top bracing broke loose and the top dropped about an inch. Gibson did repair it under warranty because I had bought the guitar new. I only use extra light strings on it now to try to avoid the problem happening again. Gibson quit using the trapeze bridge in about 1968 or 69 I think. As for sound, I have had mine next to a B 45 Gibson 12 string without the trapeze bridge and mine has the great Gibson tone but with less low end and less volume.
It did take about 20 years for the failure to happen though and at that time I didn't know about humidifiers.

Jack

Ack! My anti-virus program got into an argument with AOL, and put my computer in the shop for a week. I wish I'd gotten to this one earlier.

If you measure the forces a plucked string puts on the saddle top (as I have) you'll find there are two main ones. If the string is moving up and down relative to the top, the most of the force is 'down and up', owing to the momentum change of the string. There is another, usually smaller, signal, caused by the fact that whenever the string is pulled aside it has a bit higher tension. Because the string is off to one side or the other twice per cycle of vibration, this tension change signal is an octave higher than the 'transverse' (up and down) signal.

On a fixed bridge instrument all of these forces act on the saddle top, pushing it up and down once per cycle and also tugging it toward the neck twice per cycle of string vibration. For the low A string that means 110 up-down cycles, and 220 tugs-toward-the-neck, per second. These tugs and pulls are not 'pure' sine waves, but have a lot of higher partials in them, which are usually pretty close to 'harmonic'. The transverse wave has something pretty close to a 'square wave' form; the pull is up and steady for a time, and then switches to down abruptly. The 'duty cycle'; the proportions of down to up time, depend on where you pluck the string. The tension change signal is a sort of gapped sawtooth wave; flat for a while, with a triangular peak, and then back to flat again. You can see these idealized wave forms in Fletcher and Rossing's 'Physics of Musical Instruments", and I've got charts of the actual (messier) ones in the article I wrote for Guitarmaker a couple of years ago.

The point is that when the string is pulling upward there has to be something that keeps it in touch with the saddle top, or you've got a problem. That's what the break angle does. It seems to me that sop long as there's enough break angle to keep 'body and soul' togehter, so to speak, you're OK. The main problem with using a tailpiece on a flat top is that it's hard to get enough break angle, unless you do something like what Dennis shows. Then, of course, you've still got all the torque on the bridge that you'd have on the regular one, although you have removed the tension part of the load on the bridge glue line.

On a flat top the twice-per-cycle tension change does pull the bridge top toward the neck, and torques the top. Altering the height of the saddle above the top changes the poportion of even-order harmonics in the sound a bit. This doesn't happen with archtops, and it's one of the things (but not, IMO, the main one) that makes them sound different.

The tailpiece itself can vibrate in various ways, and that can certainly alter the sound of the guitar. The 'backstrings'; the free length between the bridge and tailpiece, can also vibrate and introduce some interesting effects.

Brad,

I'm really just talking about my own experience here, which has it's limits like all of us. All the flattops that had a tailpiece I played did not have a lot of volume compared to most 'stop' bridge flattops, as Dennis calls it. The same goes for archtop for that matter, except the difference is even greater. (Although archtops have that cool jazzy sound flattop don't have!) Maybe there are some well known makers that offer tailpiece flattops, but that doesn't mean my statement does not stand. It doesn't mean their instruments sound as loud as standard flattops do. And I'm not saying more volume means a better guitar. It really all depends on the tone you are looking for. And greater volume does not mean greater tone (altough I agree a lot of people seem to think so.)

Regarding the 'caving in' statement, I didn't know archtop instruments had to be 're-arched' eventually. Thanks for letting me know. Although that kind of reinforces my believing that a flattop with a tailpiece will eventually cave in; if an archtop caves in, surely a flattop will. Although as Alan mentioned, the brake angle being less agressive on a tailpiece flattop (which is probably why they have less volume if I understand what Alan said) the down pressure is certainly less than for an archtop.


Jack,

I'm not sure but after reading your post, you seem to agree more with me than with Brad...?


Alan,

I was beggining to think you were sick or something not to add you knowledge to this one! Thank for letting us know you taughts on this!

_________________
Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

Alain,
I think I got the posts mixed up. Yes Alain, I am agreeing with you. I was just wondering if the top bracing in my 12 string is the same as the 12 string I compared it to. Might be something for me look in to.
Sorry for the mix-up in the posts.
Jack

Man, would I ever love to hang out with you, Alan Carruth, and pick your brain, and show you some of my ideas, and buy you lunch. Sounds like your experiments do not concur with Roger Siminoff's conclusions about the major movement of a "stop" bridge.

After I built that guitar, I discovered that Ned Steinberger had patented a "system" that included a "stress free bridge", in which the strings exit off the back side of the bridge at precisely the same height as the strings entering over the saddle from the neck. In fact, he had the string straight, from the nut to the elevated tailpiece, except that it looped over the saddle, then down (for the break angle), and then back up to the exit height. Steve Grimes (and maybe Ned, I'm not sure) built the prototype, and then built a few more. They eventually sold the patent to Gibson who did nothing with it, and finally Ned bought it back and has pretty much done nothing with it. Their bridge design applies near zero torque to the soundboard (and near zero shear to the bridge.) I say "near" zero because I know the string windings do grip the bridge a little bit.

I conversed with both Ned and Steve, and though neither of them described the sound as *awesome* or *perfect*, they did say the guitars were loud with a big bass response. (They included delicate bracing.) Certainly the Steinberger/Grimes design would not be responsible for distorting or caving-in a soundboard.

My own next experiment (in progress) has the strings exiting the back of the bridge much higher, (but not quite in patent infringement territory), then passing back to a tailpiece. So, the bridge will be nearly shear free, and with a greatly reduced torque (compared to a "stop" bridge.) Maybe I'll find that a bridge "requires" torque and not just a 15° break angle to help create a great sound (by whatever subjective measure), but I'm betting the torque force will not be missed.

Anyway, this is fascinating stuff to me, and I'd love to get these guitars in your hands and get your insights and feedback.

Dennis

_________________
Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

Dennis,
I wouldn't worry about patent infringement. Check out the Bigsby tailpieces used on electrics. Same idea.