Official Luthiers Forum!

On this page you can see a restoration of a 1957 Herman Hauser II classical guitar.

I noticed in the below picture that he used parabolic bracing on this particular guitar. I thought others might find that interesting. I'll have to give that a try on my next classical

Is that curved lower harmonic brace typical of Hauser?

Thanks for the pic Graham,

I just had a conversation with Hesh yesterday about parabolic braces.
I think He said, he used them on one of his steel string guitars.
Maybe he'll chime in here, and tell us about it.

I’m with you, on trying parabolic braces!


Robert

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Everything has beauty, But, not everyone see's it!

How are you seeing parabolic bracing from the picture?

[QUOTE=Marc] How are you seeing parabolic bracing from the picture?[/QUOTE]

From the shape of them. Maybe my understanding of parabolic bracing is wrong.   

[QUOTE=Marc] How are you seeing parabolic bracing from the picture?[/QUOTE]

Marc-
Folks around here tend to classify any brace side profile that is not straight or concave/scalloped as 'parabolic'.

John

The curved lower brace was used by hauser II .recently hauser III has made a few.
He made a V shape brace but they collapsed because they were glued together at the center joint.
Notice how the braces are highest in front of the bridge.
Hauser I had some tops collapse in that area so it's plausible that his son seeing these guitars made the braces stiffer there by giving them height.
Also on these tops the thickness was usually 3mm -quite thick.
BUT they work !
Mike Collins
www.collinsguitars.com

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Mike Collins

I see now why I was confused, I was looking at the unusual curved brace below the sound hole. I didn't notice the fan brace profile.

Greg Byers Seems to do something similar.

This is something I plan to play with very soon.

Hauser II and Hauser III have experimented at different times with bracing patterns. The curved brace was in vogue for a while in the mid 50's with a couple other builders at the time trying it. It is not common in the majority Hauser II or III but were written about at the time.

Mike is correct, Hausers tend to be built heavier, both the braces and top thickness than a Spanish builder but it works and they sound good.

That curved brace works well. It opens up a bit more top area, and is quite stiff. I've been using it in my classicals over the last couple of years, with good results, I think. Here's a couple pics:

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James Warwick
J. Warwick Guitars, LLC
http://www.jwarwickguitars.com

Jim,

Could you tell us how you make the brace? From the picture it looks like you bent 2 thin pieces and then glued them together.

Thanks,

How about those tounge depressors! Probably added to repair a crack, but unbelivable. Sort of like putting duck tape on the Mona Lisa.

[QUOTE=Graham Steward] From the picture it looks like you bent 2 thin pieces and then glued them together.[/QUOTE]

Hi Graham,

Yes, that's what I did in the first top pictured. It's actually a sandwich of spruce/.010 graphite/spruce, on a redwood top.

The second one pictured was bent from a single, taller piece of spruce, on an Italian spruce top. It's also moved a little closer to the soundhole.

I'm now doing a combination of both: a "sandwich" like shown in pic#1, but thinner and taller, and moved closer to the soundhole, like pic#2.

Best,

Jim

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James Warwick
J. Warwick Guitars, LLC
http://www.jwarwickguitars.com

[QUOTE=JWarwick] That curved brace works well. It opens up a bit more top area, and is quite stiff. [/QUOTE]

Im trying to see how its opening up more top area. From the photos it looks like youve in fact got slightly more top area braced with the curved brace and the outer fan struts running into the area adjacent to the soundhole.

[QUOTE=kiwigeo] Im trying to see how its opening up more top area. From the photos it looks like youve in fact got slightly more top area braced with the curved brace and the outer fan struts running into the area adjacent to the soundhole. [/QUOTE]

The additional soundboard area I'm referring to is the area bewteen an imaginary line tangent to the curved brace at the soundboard center line(roughly representing where a more traditional straight transverse brace would be placed)and the curved brace. By "opening up" I simply mean involving more top; yes, that area is braced, and quite rigid.

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James Warwick
J. Warwick Guitars, LLC
http://www.jwarwickguitars.com

I understand the objective of the curved brace to create a larger vibrating area in the lower bout but have concerns about the curved brace eventually letting go as it is laminating under tension. I am not critical of it but rather just not sure how it will hold up in the long term.

To increase the vibrating area the bracing pattern I use is to have open crossbars with braces running through them towards the sound hole. This is the design that Jose Romanillos uses and is based on some existing Torres guitars that used open crossbars.

The crossbars above and below the soundhole have open areas where braces extend down from the heel toward the main crossbar and from the main crossbar to the top crossbar. There are several of the other builders that also attended Jose's class that also use that pattern or some variation of it.

The 5 brace fan you have pictured above does not have the lateral end braces. Is this a flamenco pattern or do you use it for your classical? I typically do not do the laternal end braces when bracing for a flamenco as it helps the sound to be loud but with a rapid decay which is preferrable for a flamenco but would be harder to control in a classical.

[QUOTE=Shawn] I understand the objective of the curved brace to create a larger vibrating area in the lower bout but have concerns about the curved brace eventually letting go as it is laminating under tension. I am not critical of it but rather just not sure how it will hold up in the long term.[/QUOTE]

I know the concern. I do bend the spruce over a hot pipe before laminating, hopefully minimizing any tension issues.

[QUOTE=Shawn]To increase the vibrating area the bracing pattern I use is to have open crossbars with braces running through them towards the sound hole. This is the design that Jose Romanillos uses and is based on some existing Torres guitars that used open crossbars.

The crossbars above and below the soundhole have open areas where braces extend down from the heel toward the main crossbar and from the main crossbar to the top crossbar. There are several of the other builders that also attended Jose's class that also use that pattern or some variation of it.[/QUOTE]

I've seen that illustrated in Courtnall's book, but haven't tried it. I'd like to take his class.

[QUOTE=Shawn]The 5 brace fan you have pictured above does not have the lateral end braces. Is this a flamenco pattern or do you use it for your classical? I typically do not do the laternal end braces when bracing for a flamenco as it helps the sound to be loud but with a rapid decay which is preferrable for a flamenco but would be harder to control in a classical.[/QUOTE]

Yes indeed, both of these tops went on flamenco negras. I generally agree with you about lateral end braces and use them on my classicals.

Best,

Jim

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James Warwick
J. Warwick Guitars, LLC
http://www.jwarwickguitars.com

I remember a while back in GAL Tim Olsen used a curved lower brace with a lot of success. In his design he also used a diagonal harmonic bar. I was thinking about trying it out with my lattice braced classical tops, how do you think that might work out?