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I'm having some trouble designing a guitar. In my quest for information for this next build, which will be lightly braced and have a tailpiece, I have come across a couple customs that intrigued me.
Two reviews have both mentioned the wolf notes given off from the section of string past the bridge; One of which ended up weaving a thread around the strings to mute the overtones.
While happy with his instrument he thought it'd be cool to have figured out a way to make those overtones more in tune to his guitar

And so do I...but I'm kind of a dummy trying to figure this out
You could tune it to sound great while playing open notes, say tuned to a 5th or 7th or whatever but those wolf notes are only tuned to that specific note.
Maybe it's not worth the trouble of finding a relative note in relation to each string but to try to tune them all up in the same scale, sort or like piano tone bars or tap tuning parts of a guitar.

As for violins, I saw one bit of info that says the optimum length of string on the other side of the bridge should be 1/6th the scale length.
I'm probably incorrect in the thinking that follows but bare with me.
That would be a little over 4 inches on a 25.5" scale guitar
so trying to investigate this I placed my finger on imaginary frets listening to the harmonic 4 inches from the bridge on the low E. It sounds pretty terrible. About 6 inches from the bridge is probably where the 24th fret would be and gives another E. Perhaps a good length for the tailpiece to bridge?

Anyways, please discuss and add any links or comments about sympathetic string vibration.
Thank you!

Here's a couple of reads I found interesting
http://www.stringsmagazine.com/article/ ... leid=25864
http://buildingtheergonomicguitar.com/2 ... round.html

Have you built a conventional guitar yet? That would be a good way to start. Then the next thing to do is build another conventional guitar.

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

When all else fails, clean the shop.

And on and on!

_________________
Waddy

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Sound Clips of most of my guitars

Tailpieces add another level of complexity to something that's already pretty complicated. This can be good: part of the charm of the sound of the guitar is that complexity. It can also be a problem, in that resonances of the tailpiece itself or the back strings can couple with top motion in ways that make trouble.

That ''1/6th rule" for violins is sometimes taken as gospel, but most of the more experienced makers I know see it as a decent place to start. Sometimes setting up a violin like that really works out well, and sometimes you need to tweak it a bit.

Obviously, if you go by that rule, the back strings will have resonant frequencies at about six times those of the fundamentals of the played part of the string. These can effect the sound of the guitar, and often it does help to damp these vibrations out.

The actual tailpiece resoances, particularly the one where the TP swings up and down on the hinge of the tailgut, can also effect the tone of the guitar. Predicting that pitch in advance would be tricky: it depends on the mass and center of moment of the tailpiece, and the tension of the strings. a slight change in something like the tailgut length can alter the pitch enough to make a real difference.

On my first archtop classical guitar I wanted to enhance the bass. I found that a piece of lead on the tailpiece would drop it's pitch to match that of the 'main air' resonance. Since the tailpiece as it swings up and down puts a force on the top of the bridge this tailpiece resonance was coupled with the air mode through top motion, and it helped to broaden the 'main air' peak in the output and give it more power.

I took the guitar to show to my friend, Aaron Green. He was not in, but his shop buddy, Steve Connors, was, and he was playing the instrument as Aaron walked in. Aaron asked about the lead weight, and I reached over and pulled it off (it was stuck on with double sided tape). Aaron exclaimed: "Who turned off the speaker!".

Jim D'Aqiusto used to say he could 'tune' the response of one of his archtops through a very broad range simply by changing the tailpiece. I believe it. But I don't think even he knew in any exact way what effect the first tailpiece was going to have before he actually put the strings on. I don't think this is something you can 'design' in advance; you just have to make the guitar and work out the best tailpiece for it afterward.

great info Alan.
I'm just about to buff the topcoat on my first guitar. A conventional OM
Pics to follow as soon as I shape the nut and saddle
I'm sure I'll be trying out different tailpieces then to get a sound I'm happy with
It seemed to me that the balance of light braces but not so light the guitar implodes on a conventional would be much harder than lightly bracing a guitar with a tailpiece.

Wow.