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Guitar tone bar questions
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=49839		 Page 1 of 1
Author:  SnowManSnow [ Sat Oct 21, 2017 10:32 am ]
Post subject:  Guitar tone bar questions
Ok first, let me say there are varying ideas on what a tone bar actually does.
1- it spreads vibrations across the bout and is the “bar” by which the tone travels
2- it “bars” certain tones from proliferating. Or in other words it dampens certain tones.

So my first question is: which is it?

The second observation I have made recently, and I hope someone can speak to, is: what about those guitars with only one tone bar? Are these normally smaller OM or 000 instruments? Is it to free up the lower hour to be more responsive? Is there meaningful integrity loss on the top?

Thanks for the insight!
B


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Author:  kencierp [ Sat Oct 21, 2017 11:24 am ]
Post subject:  Re: Guitar tone bar questions
Mainly keep the sound board from splitting along the grain.
Author:  Pmaj7 [ Sat Oct 21, 2017 11:30 am ]
Post subject:  Re: Guitar tone bar questions
Yes, smaller guitarists typically will have less tone bars. Tension could be a factor too. Such as a 12 string guitar of the same size as a 6-string typically has three.
Author:  Pmaj7 [ Sat Oct 21, 2017 11:31 am ]
Post subject:  Re: Guitar tone bar questions
pat macaluso wrote:
Yes, smaller guitarists typically will have less tone bars.
same goes for smaller guitars!
Author:  DennisK [ Sat Oct 21, 2017 11:54 am ]
Post subject:  Re: Guitar tone bar questions
They add some stiffness. Without them, a typical thickness top will belly excessively behind the bridge. The tone bars hold the belly down.

By my way of thinking, the optimal spacing between braces depends on the thickness of the top. If there aren't any squishy feeling spots between braces, then you have enough. 12 fret guitars have a smaller south quadrant, so that's one way you can end up only needing one tone bar.

I wouldn't use 3 tone bars on a 12 string, because the top will likely be extra thick anyway, and I could just increase the height of the two that are already there to increase the stiffness with much less weight penalty.

It's possible to make the soundboard thick enough that you don't need fingers and tone bars at all. Best to do on small guitars, with low density wood like western redcedar or redwood so the total soundboard mass remains low. And it may not be the best idea in terms of split prevention. But those woods have low humidity expansion, so you can brace dry to make them more or less humidity proof.
Author:  Freeman [ Sat Oct 21, 2017 12:32 pm ]
Post subject:  Re: Guitar tone bar questions
I have conflicting feelings about these things. I have built 3 small bodied guitars from a set of plans that are drawn as though you were looking thru the top - the first one I braced backwards, the second and third "normally". The first was scalloped, the second and third were profiled. Tops were all spruce, bodies rosewood.

Image

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They sound different.

I've also built two Weissenborns using the same pieces of koa for tops, sides etc. One was braced in traditional style with ladder tone bars, one with angled tone bars

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They sound different, but its subtle.

And on my X braced 12 strings I do follow Taylor's lead and use three tone bars and very slightly thicker tops. I had too much belly on an old Martin 12 with standard bracing.
Author:  jeffhigh [ Sat Oct 21, 2017 2:28 pm ]
Post subject:  Re: Guitar tone bar questions
Don't read too much into the name "Tone Bar"
It's just a name that has become widely adopted, not a description of it's function.
As other posters have said, it's just a way of adding a controlled amount of stiffness.
Author:  Haans [ Sat Oct 21, 2017 2:54 pm ]
Post subject:  Re: Guitar tone bar questions
Lots of Larsons were square and un-tapered, but scalloped at the ends.
Bout the same as a big ladder back there anyway. Just spread out more. Sound is a different story. I'm sure they do something but it's all speculation...
As far as twelve strings, most all of you talk apples to my oranges.
Author:  Pmaj7 [ Sat Oct 21, 2017 4:13 pm ]
Post subject:  Re: Guitar tone bar questions
Haans wrote:
As far as twelve strings, most all of you talk apples to my oranges.
Can you elaborate?
Author:  Haans [ Sat Oct 21, 2017 4:33 pm ]
Post subject:  Re: Guitar tone bar questions
Everyone that uses ladder braced, very thick red spruce topped, mahogany backed, .070-.014" strings, Tuned to B, with a 26+" scale raise your hand...

[clap]
Author:  James Orr [ Sat Oct 21, 2017 6:20 pm ]
Post subject:  Re: Guitar tone bar questions
Beyond adding stiffness, it's going to influence the way the top moves under energy. Ervin Somogyi gave a "voicing" seminar at Healdsburg about a decade ago which LMI sold a video of. I didn't learn how to make my guitars sound like a choir of angels from it, but I was absolutely fascinated by models he used to demonstrate the way the arrangement of the braces influence the top's movement.

The models were put together connecting bracing schemes to a frame using leather and springs. He activated the tops by striking the middle of the X or something. The differences were significant. It's definitely worth finding to watch and sell if you don't want to keep it.
Author:  Freeman [ Sat Oct 21, 2017 7:03 pm ]
Post subject:  Re: Guitar tone bar questions
Haans wrote:
Everyone that uses ladder braced, very thick red spruce topped, mahogany backed, .070-.014" strings, Tuned to B, with a 26+" scale raise your hand...

[clap]


I like both apples and oranges

Image
Author:  Haans [ Sun Oct 22, 2017 7:28 am ]
Post subject:  Re: Guitar tone bar questions
There's a whopping 1/2...
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