Andreas Preuss’ New Concept Violin (formerly: super light violin)

[Andreas Preuss]

On 10/4/2018 at 12:50 AM, Danube Fiddler said:

To thin down (the back) from the outside 20 g is really a lot. 

However let me do these comparisons : 

           super-light-violin         Guarneri-del-Gesú (average Plowden/Rode/Kubelik [ Terry´s CT-data])

Back    105 g                              88g 

Top        66 g                                63 g  ( probably without bassbar; may be 67 with bassbar )

                                                   tops of Booth and Kreutzer - Strads ( Curtins data ) ~ 55g (without bar)

Would you agree to rename your project into  " normal old-italian-weight-project" ?

007-76.1 For thinning down the back from the outside it depends where you start. My back is right now 130g so going down to Guarneri weight I could reduce 40g. 

76.2 From the beginning I had no intent to touch the parts of the violin which are crucial for the sound. It would be stupid to make a 300 -330g violin which doesn't sound. In this sense you are right it is normal old Italian weight project.

BUT

76.3 I used new ideas to reduce weight on all other parts and in a way which hardly can support the attribute 'old Italian' :

1. Laminated ribs, balsa corner blocks and guitar linings constructed on an outside mould.

2. Spruce neck graft

3. Minimized scroll design

4. Surface of the top plate bigger than the back plate 

4. Assymmetric ergonomic design

Sorry, can't rename the project.

 

[Andreas Preuss]

On 10/4/2018 at 12:50 AM, Danube Fiddler said:

tops of Booth and Kreutzer - Strads ( Curtins data ) ~ 55g (without bar)

007.-77.1 Concerning the super light tops of Strad I have to comment that nobody knows exactly how they were made. My hypothesis is that he worked with weight, but what we measure today was not the weight Strad aimed at when closing the box. I think this must have been around 60g without bass bar. The rest was shaved off when finishing the edge work at the closed box. If this was done with the purpose of sound adjustments is disputable. 

77.2 My top isn't finished either and I can certainly shave off safely another 3-4g around the edges which brings it close enough to the weight of Strad tops. 

77.3 I tried to go below the 55g mark by bending the top. So far I couldn't make it work. After 3 failed attempts I thought it is better at this stage to continue normally. But this doesn't mean it's the end of the story. I think I know now why it went wrong and can make the next super light violin with a bent top where I am expecting to come down with the weight of the top around 55g with bass bar.

[Danube Fiddler]

14 hours ago, Andreas Preuss said:

For thinning down the back from the outside it depends where you start. My back is right now 130g so going down to Guarneri weight I could reduce 40g. 

From the beginning I had no intent to touch the parts of the violin which are crucial for the sound. It would be stupid to make a 300 -330g violin which doesn't sound. In this sense you are right it is normal old Italian weight project.

BUT

I used new ideas to reduce weight on all other parts and in a way which hardly can support the attribute 'old Italian' :

1. Laminated ribs, balsa corner blocks and guitar linings constructed on an outside mould.

2. Spruce neck graft

3. Minimized scroll design

4. Surface of the top plate bigger than the back plate 

4. Assymmetric ergonomic design

Sorry, can't rename the project.

 

Now I understand your project basically - I didn´t follow it before.  Sorry for my stupid question.

 

[Andreas Preuss]

007.78.1 So here is the last update on the super light violin. After I glued the neck and trimmed it roughly I am at 267g. 

78.2 Now I am working on a baroque style fingerboard trying to get a weight of 40g. Accessories are 44g. varnish 4g.  So this would come down to a total of 355g before making the final adjustments from the outside on the back (minus 20g) and trimming the edge on the top ( minus5g) This means that the initial high estimate of 330g is absolutely in reach. 

 

[Dominik Tomasek]

Dear Andreas,

would it be please possible to post more photos of the spruce neck? I am ridiculously curious about it! 

[Andreas Preuss]

On 10/5/2018 at 12:30 PM, Dominik Tomasek said:

Dear Andreas,

would it be please possible to post more photos of the spruce neck? I am ridiculously curious about it! 

007-79.1 It has a new graft type to make it the least visible from the front. (Not for beginners!)

Because spruce is too soft to hold in the neck mortise I glued a piece of maple on the neck heel.

A spruce neck seems to be good in terms of stability (high longitudinal strength) but not so resistant to wear. Therefore I am planning to penetrate the surface with a very sweat resistant varnish. 

[Dominik Tomasek]

Thanks Andreas! Great work and perfect idea with the maple piece.

[Nick Allen]

It will be interesting to see if it holds up to string tension over long periods. 

[JacksonMaberry]

Should beat maple on string tension, but not wear. 

[Nick Allen]

2 hours ago, JacksonMaberry said:

Should beat maple on string tension, but not wear. 

Really? I never would have thought. 

[JacksonMaberry]

I could be wrong, but I think so. Spruce is unbelievably strong longitudinally. 

[Andreas Preuss]

On 10/8/2018 at 8:37 PM, Nick Allen said:

It will be interesting to see if it holds up to string tension over long periods. 

007-80.1 Have done that in restorations I don't know how many times. Rene morel called it neck reset. 

Basically the risk that it gets loose is minimal because the string tension presses both pieces together. Only at the bottom there is a pull on the joint which is only risky when the neck root gets loose at the button surface.

[Andreas Preuss]

On 10/8/2018 at 11:52 PM, JacksonMaberry said:

I could be wrong, but I think so. Spruce is unbelievably strong longitudinally. 

007-81.1 The very reason for which spruce is used as a material for the top and not maple. 

I made actually a test before deciding to do the graft with spruce. I made from spruce and maple two test pieces of the size of the neck without the neck root. The comparison showed that spruce is stronger lengthwise. 

[Andreas Preuss]

On 10/8/2018 at 10:30 AM, Dominik Tomasek said:

Thanks Andreas! Great work and perfect idea with the maple piece.

007-82.1 Besides, the absolutely best glue for such a joint is gorilla glue. The only disadvantage is that the joint line will always show. But if the maple piece is just lower than the rib surface it is basically invisible.

[MANFIO]

Perhaps pining the spruce neck heel would be a good idea.

[Andreas Preuss]

On 10/13/2018 at 2:48 PM, MANFIO said:

Perhaps pining the spruce neck heel would be a good idea.

007-83.1 That's what you do when glueing with hot glue. With epoxy or gorilla glue  I don't think it is really necessary. 

[Nick Allen]

6 hours ago, Andreas Preuss said:

Have done that in restorations I don't know how many times. Rene morel called it neck reset. 

Basically the risk that it gets loose is minimal because the string tension presses both pieces together. Only at the bottom there is a pull on the joint which is only risky when the neck root gets loose at the button surface.

Good to know as I've done that too. 

I was referring to the softwood neck, though. 

[Andreas Preuss]

On 10/13/2018 at 2:48 PM, MANFIO said:

Perhaps pining the spruce neck heel would be a good idea.

007-84.1 That's what you do when glueing with hot glue. With epoxy or gorilla glue  I don't think it is really necessary. 

[Andreas Preuss]

On 10/13/2018 at 8:25 PM, Nick Allen said:

 

I was referring to the softwood neck, though. 

007-85.1 The problem with any fir type of wood is that it is less resistant to wear as we know from the edge of the top where players touch it to reach high positions. 

85.2 For the moment my solution is to impregnate the surface with a hard and durable varnish. Maybe even crazy glue as a filler could be an option. 

85.3 For the mechanical properties I am really curious how this works. I am using here red cedar (?) which seems to be for the lengthwise elastic modulus lower than maple but seems to  have a higher sound of speed. 

85.4 Next time I am trying to get hold of Douglas fir for the neck because all the data seem to be favorable. High elasticity modulus and high sound speed and low relative weight. 

 

[Andreas Preuss]

007-86.1 Some more data on the super light violin: 

The Helmholtz air resonance A0 is without sound post around 247Hz measured by humming into the f hole which seems to be just right because the sound post raises the frequency about 30Hz. 

Was wondering though what a higher than usual air resonance would do to the sound.

 

 

 

[Andreas Preuss]

007-87.1 So now I am making a baroque type fingerboard. Because I don't like the idea of laminating a spruce core with 1mm ebony veneer I used an old fingerboard, thinned if down to 2mm and fitted it to the spruce core. This allows the fingerboard to be trimmed more often. To save weight I am planning to thin down the ebony layer towards the bridge end 

87.2 Unlike classical baroque fingerboards the ebony sides are attached last to avoid that the joint will be at the side where the risks bigger that the joint opens during extensive use.

Weight of the fingerboard at this stage 66g.

[JacksonMaberry]

Andreas,

When I make my baroque boards, the ebony veneer is slightly thicker than 2mm. Probably easier than chalk fitting, but both ways work fine I'm sure. 

Also, it looks like you put an ebony cap on the bridge end of the board. That seems unnecessary, and might cost you as much as a gram, maybe two. A little India ink would have done the trick.

[Andreas Preuss]

007-88.1 

Jackson,

the use of an old fingerboard was half decided by the fact that I didn't have nice 2mm ebony boards in my workshop long enough for a fingerboard. Bending is of course faster and easier.

88.2 The cap was not necessary and certainly adding weight but only the difference between the cut away spruce and the ebony piece  fit in its place. So certainly less than one gram and I wanted the fingerboard look like a normal one. Inked spruce can't be polished!

88.3 I am planning to leave the neck a little thicker and make the fingerboard a little thinner for the same standard measurements of the neck 18.5 - 20.5. This will make the free end of the fingerboard a bit lighter.

88.4 When the fingerboard is glued and the setup in the white is finished the first sound adjustments can start. 

88.5 For the sound adjustment 3 steps are planned:

1. Raw setup adjustment in the white but with 2 different sound posts and 2 different bridges. At this stage I'll finish the top edge only to see if anything in the sound changes. If not this step will be skipped the next time. 

2. Adjustment after only the top has been varnished.  At this stage I am planning to adjust the back plate from the outside with the goal to make the 'central island' in the thicknesses of the back. 

3. After varnishing the rest of the instrument, the last adjustments are made, the usual set up stuff with sound post, bridge and strings.

[JacksonMaberry]

Understood. Great stuff! Very eager for some hi-def audio samples

[Andreas Preuss]

007-89.1 Even 'simple' things like the fingerboard have importance for the entire weight.

The fingerboard at this stage has only 46 g and by trimming it to its final shape I estimate a loss of 10% coming down to 41g. 

The entire violin with pegs, sound post bridge boxwood tailpiece endpin and strings weights right now 349g