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

[Andreas Preuss]

 

16-197.1 Here are the first sound graphs from setup in the white. 1. Bowed chromatic scale high resolution, 2. Same, but low resolution

 

 

16-197.2 parameters of the first test-setup:

I used a normal Milo Stam bridge (instead of my own asymmetrically designed bridge). There is an ebony test fingerboard used at this moment which is approximately 15g heavier than the fingerboard I’ll be using. The asymmetric outline made it aesthetically necessary to design my own tailpiece which came out at 6g. (More of that in a later post) I am using Knilling pegs. 

 

Total weight  without chinrest is 327g. Edges of top and back are not rounded off and might reduce the weight another 3-4g.

String angle 157 degrees

Bridge weight 1.8g at normal thicknesses 

Standard sound post position

——————————

16-197.3 At this stage I am satisfied with the sound result considering that the whole construction was following not precisely the construction of the proto type model. The alterations I made on 1. rib construction, 2. top plate construction and 3. back arching shape made me sometimes wonder if it wouldn’t end up in unwanted sound effects.

 

197.4 I am especially relieved to see that there is enough meat in the frequency range above 1.5kHz up to 6 kHz. In total I would describe the acoustic properties as ‘functional’ with an interesting slightly rough timbre. It is a good basis for further sound calibration. Weakest point is an imbalance between G and D string where the G is a little too strong (loud) compared to the D string.

 

[Arbos]

Apart from the graphs, what’s the experience of playing it like? Does it react differently under the bow? Would really like to try this violin, looks fascinating.

[Andreas Preuss]

On 1/11/2025 at 4:49 PM, Arbos said:

Apart from the graphs, what’s the experience of playing it like? Does it react differently under the bow? Would really like to try this violin, looks fascinating.

16 - 198.1
Any professional musician is very welcome to try the New Concept Violin. 
 
From my perspective as an amateur player the experience of playing it is ‘normal’. 

When it comes to sound I am mostly interested in two things

resistance

overtones

There are still details I have to work on and understand better. 

 

[Don Noon]

On 1/5/2025 at 3:29 AM, Andreas Preuss said:

the G is a little too strong (loud) compared to the D string.

My initial impression of your response plots was that the B1+ region (500-600 Hz) was excessively strong.  I would expect it to show up primarily on the A string, but it's also the first overtone of the low G string range, which could make it a bit "loud".  If the fundamentals on the G string were too strong (which doesn't show on the plot), you might use "round" or "tubby" descriptors rather than "loud".

Excessive power in the B1+ range is something I found in my attempts at making light/stiff top plates.  Also, I found more power than desirable around 1 kHz and something about the higher overtones that wasn't quite right to my ear.  The net result was loud, but midrangy; it was light on the lows and highs.  Alternatively, a light top that was not stiff enough became too bottom-heavy or tubby.  I gave up the experimentation with ultralight almost a decade ago, although I have a spruce set that I want to use someday for one last experiment... more of the Cannone idea of very stiff but not ultra light.

Your results may be different.  Good luck.

 

[Andreas Preuss]

On 1/13/2025 at 1:55 AM, Don Noon said:

Your results may be different.

016 - 199.1

As far as I can say, there is a fundamental differences due to the unusual construction of the rib garland. Stiff ribs seem to support a weak top (much) better. So I’d say my result is different. 

182.2 Now after a simple modification I could solve the problem of the weak D string satisfactory. I lowered the arch of the ribs on the top side 4mm with the result that the D string blends perfectly into the rest, almost the way I predicted it:

 

177.10 Expected results

Starting the calibration process with a too highly arched top, it is expected that the sound is (and should be) sub optimal in different aspects: sound quality, loudness, response. Before the calibration process starts, the sound is expected to be thin, sharp, and not too responsive. (Just a wild guess)

The simultaneous alterations in the AFOC process is expected to create an equilibrium for the dynamic behavior. (when the violin is played)

199.3Looking at this comment now, it is pretty accurate. The D string was ‘Thin, sharp and not responsive’ and didn’t match with the overresonant G string. My prediction was perfectly accurate in how problem could be solved just by lowering the arched ribs on the top side. 
 

199.4Here are again two graphs in high and low resolution respectively: 

The B1+ seems to be still relatively high though, but it doesn’t result in a midrangy sound.  (According to your description of midrangy I would rather say ‘flat sound’ or ‘meager sound’ where there is neither depth nor colors but still can be loud)

199.5 I am looking on the graphs more on the patterns above 1.5kHz. I am pretty sure that if you get in the high frequencies the ‘right’ constellation, moderate irregularities in the signature modes don’t matter so much. Right now the sound is on the darker side but with a good richness so that it definetly does not sound tubby. For a more poetic description I would say ‘creamy texture’.

199.6 In total I am content with the progress. At least I can say that I have been at the same weight and the best description of the resulting sound was ‘catastrophe’. Now it’s a balanced and playable instrument where its specific sound characteristics are a matter of taste. 

199.7 Regardless, there are future challenges which might become much more complicated. I am still not quite sure if the ‘resistance’ is right, also I am asking myself if it is possible to manipulate the structure to achieve particular sound characteristics such as ‘textured’. 
 

 

Edited January 17 by Andreas Preuss
insert graphs

[Andreas Preuss]

16-200.1

Latest alteration on the rib cage was to deepen the concave curvature on the back side, so that the ribs have a uniform height. The sound seems to have gained more soprano character. the reason for this seems that the peaks below 1500Hz got in average lower and B1+ is not sticking out so much. 

200.2 When played, the overall balance is very good, single notes are smooth and rich. As far as I can judge the `resistance` also seems to be good, but how good is beyond my capabilities of bowing technique. 

200.3 For my personal taste there could be still more texture in the sound, the kind of edgy feeling. In some way this sound characteristic reminds me of rubbing two ballons against each other.

200.4 So here are the graphs again in high and low resolution respectively.

 

 

[Don Noon]

There are plenty of reasons to suspect any comparisons between different people with different equipment trying to compare Audacity plots, but there's not much that can be done about it other than be suspicious.  However...

Here is my bowed response of the 1714 Ex-Jackson at low resolution.  A few features stand out to me... 

Below 1kHz, it's pretty level.

There's a dip just above 1kHz

From about 1.5kHz to 3.8kHz there's solid response, an drops off rapidly after that.

I should note that I have never built anything that had this shape of response, and have never measured any other violin, new or old, quite like it either.

I would suspect that the New Concept Violin lack of "texture" might be a result of the very narrow "bridge hill" which only starts above 2kHz and cuts off at 3kHz.

[Andreas Preuss]

On 1/31/2025 at 2:42 AM, Don Noon said:

I would suspect that the New Concept Violin lack of "texture" might be a result of the very narrow "bridge hill" which only starts above 2kHz and cuts off at 3kHz.

 

16-201.1

Thanks for your thoughts. Would you say that the ex-Jackson has a textured sound? Then there is certainly useful information in the FFT spectrum. It would also be interesting to know a few parameters of the setup like string angle, bridge weight, string type. 

------------------------------------

201.2 However, this might be now interesting. After some days thinking how to proceed further i decided to open the top and reinforce the crossgrain bars which form approximately the nodal lines of mode 5. My hypothesis was always that cross stiffness has an impact on overtones.

201.3 First Impression after setting up the violin was positive. It lost basically the dark sound timbre and became much brighter. Adjustment of soundpost and bridge could actually create different patterns in the sound response over 1.5 kHz. The first adjustment had to me a smother sound the second had more texture. But there was also a difference in how it felt under the bow which is a bit hard to describe. 

201.4 So here is in low resolution the smooth adjustment

 

And for comparison the textured sound adjustment. 

 

201.5 For the textured sound I had to move the bridge towards the treble side f hole, so that is was about 2mm off center and at the same time I flattened the string angle from 158 to 159 degree.

 

 

 

[Don Noon]

5 hours ago, Andreas Preuss said:

Would you say that the ex-Jackson has a textured sound? Then there is certainly useful information in the FFT spectrum. It would also be interesting to know a few parameters of the setup like string angle, bridge weight, string type. 

I would say that the low strings are more smooth and round sounding, and the highs are very pure and clear.  I suspect that the "Dunnwald dip" weakens the overtones of the low strings to smooth them out, and the solid "bridge hill" response gives the clarity to the highs.  I don't have details on the setup, other that it's from the best luthiers around.

It looks like your recent modification might have strengthened the highs a bit, but still somewhat the same basic shape.  The big hill at the B1+ looks worrisome, especially with relatively weak response below that (A0, CBR, B1- resonances).

I really don't like the top reinforcements, with multiple beams in several directions, and think it might be responsible for some of these issues.  Struts tend to reduce the number of vibrating mode shapes, which in turn should give a more choppy response, with strong peaks and dropouts.  A violin has a small soundboard to start with, and reinforcements just break it up into even smaller patches.  I would try a normal bass bar, perhaps a bit heavy to attenuate the B1+ resonance.

[Andreas Preuss]

On 2/2/2025 at 6:14 AM, Don Noon said:

It looks like your recent modification might have strengthened the highs a bit, but still somewhat the same basic shape.  The big hill at the B1+ looks worrisome, especially with relatively weak response below that (A0, CBR, B1- resonances).

16-202.1 

Actually somehow I was puzzled. As long as the instrument was sounding dark I would have thought that your analysis is right. 

202.2 Maybe I found the mistake. In the recording below I turned away from the microphone and recorded the following graph which doesnt show the strong B1+ anymore. So there must have been something wrong in my recording setup. (?)

 

202.3 Concerning the cross bars I was also hesitating to do it. But because my top plate at thickness of 1.6 - 2.0mm is beyond the point that a traditional bass bar can be installed with good results, I need to think about unconventional options. Creating a flexible grid seems to me a possible option. Somehow the idea comes from restoration workshops who would never install a patch on a top plate which is considered too thin. So they would increase the stiffness with well placed studs.

 

202.4 I have also in mind to reduce the stiffness of the crossbars again when it seems necessary. At the moment when playing the New concept Violin it sounds good and balanced. Or in your terms 'there are no glaring issues' I can hear. 

202.5 If I view the progress in a self critical way I would like to get a better response on the A0 and more peaks between 3kHz and 4 kHz. 

On 2/2/2025 at 6:14 AM, Don Noon said:

and reinforcements just break it up into even smaller patches. 

But wouldn't 'smaller patches' be better suited for high frequencies? 

[Don Noon]

6 hours ago, Andreas Preuss said:

But because my top plate at thickness of 1.6 - 2.0mm is beyond the point that a traditional bass bar can be installed with good results,

If it was very dense, super-stiff spruce, maybe it could work.

6 hours ago, Andreas Preuss said:

But wouldn't 'smaller patches' be better suited for high frequencies? 

Perhaps SOME high frequencies would be strengthened... but you need patches of all size in order to get a wide range of frequencies.  A large-ish patch will naturally subdivide itself into a variety of mode shapes depending on the input frequency.  If you attach stiffening struts, it will likely result in less modal density and more uneven response.

 

[Andreas Preuss]

On 2/3/2025 at 5:21 AM, Don Noon said:

Perhaps SOME high frequencies would be strengthened... but you need patches of all size in order to get a wide range of frequencies.  A large-ish patch will naturally subdivide itself into a variety of mode shapes depending on the input frequency.  If you attach stiffening struts, it will likely result in less modal density and more uneven response.

 

16-203.1

In theory this is certainly correct. In practice there might be some differences which come (in my oversimplified view) from the following thoughts:

 

203.2 A reinforcement grid on an arched plate will disturb the mode pattern only in a negative way if its own stiffness is much larger than the stiffness of the plate. We may think of a reinforcement grid which is flexible in itself. One method to avoid effects of local ‘over stiffening’ on a non linear and more complex reinforcement grid would be simply to thin down the thickness of the beams. Also their shape can help to avoid this. (I believe that the curved shape is for this type of ‘bass bar’ better than straight beams forming a square grid) If we imagine to use a paper thick reinforcement grid it has certainly hardly any effect measured against a plate without reinforcement grid. Now, if we increase gradually the thickness of all beams we can get to a point where we have the directional strength needed without sacrificing elastic properties in an unfavourable way. 

 

203.3 This in mind I installed actually one more bar: this time in the center crossing the c bouts from one side to the other. (But also slightly curved) 

When playing the instrument I couldn’t detect any direct and obvious negative effects. Rather the opposite. 

 

203.4 In my old audicity files I found one I made from a CD where Perlman plays Bachs Chaconne. I think it is an interesting comparison for the unsharp image of a low resolution graph. (I do this also because I needed some other comparisons than the Ex-Jackson) In the end I am not intending to make a sound clone.

203.5 On a higher resolution there is at least one thing clear: the air resonance on Perlman’s instrument had a better response and I DO see this as an upcoming challenge. 

PERLMAN

 

 

 

NCV with one spruce crossbar (2mm thick) between c bouts. Its vertical thickness is shaped like and arch. 

For my personal taste it sounds balanced has depth and no major issues, the B1+ still seems to be strong but I couldnt detect a wolf note. It sounds to me more interesting than many violins I have made in the past. 

[Don Noon]

18 hours ago, Andreas Preuss said:

A reinforcement grid on an arched plate will disturb the mode pattern only in a negative way if its own stiffness is much larger than the stiffness of the plate.

If the grid is stiffening the plate to any degree, there will be local areas around the beams that are significantly stiffer than the areas away from the beams.  This would be especially true for crossgrain beams, where the spruce is very wimpy.  The mode shapes and frequencies will be different when compared to an unreiforced plate... unless the grid spacing is much closer that the higest frequency antinode patch, AND the grid is carefully adjusted to match the natural anisotropy of the wood.

None of this is to say any of the effects will necessarily be positive or negative, although in general I would expect modes to be more widely spaced in frequency and more variable in amplitude.  In my mind, that would tend to be undesirable... but who knows.  Also, with glue and such, I would expect adding a reiforcing grid to increase damping.

[Andreas Preuss]

So after numerous experimentations which I didn't really find worthwhile to post here, I am now continuing to finalize the New Concept Violin. I remade the whole bass bar system to imitate a previous state (16-201.1) which I thought was best sounding so far. 

So here are the latest sound graphs for the best setup i could achieve. For this setup i also thinned the bridge further down to a slim 3.3mm. Experiments with the string angle came always back to the flatter 158 degree angle for a better overall balance. It took a couple of trial and error steps to bring out the resonances above 3khz. Somehow the 'trick' was moving the bridge up and down in N-S direction to find the right spot. I have actually no logical explanation for this other than that there seems to be trigger point location and the last move I made was probably only 1 or 2 tenth of a millimeter which made in the end the difference. 

The first two resonances around 230 and 310 Hertz got notably stronger, something which was the purpose of all the reconstruction work. Somehow the low frequencies seem too strong now. So for the very last correction I need to tune those resonances again a little down to lighten up the lower notes which sound at the moment very (too) dark for my taste. 

 

 

Here on the second high resolution graph one can see a strong resonance at 230Hz which seems to be too strong.

 

 

[Don Noon]

The spectrum looks more like a viola to me than a violin.  Presumably A0 is 230 Hz (normally 270 or more), CBR is 310 Hz (normally 350 or more), B1- is 400 Hz (normally more like 430), and I can't tell where the B1+ resonance might be.

While that isn't necessarily a bad thing, I would expect violinists to find it "different"... which is usually not so attractive in the violin world.  But the low frequencies are just a small part of the spectrum, and the rest might be good.  Do you find that the low E string has some loud notes that might be due to the peaks in the 700 - 800 Hz range?

[Andreas Preuss]

13 hours ago, Don Noon said:

The spectrum looks more like a viola to me than a violin.  Presumably A0 is 230 Hz (normally 270 or more), CBR is 310 Hz (normally 350 or more), B1- is 400 Hz (normally more like 430), and I can't tell where the B1+ resonance might be.

While that isn't necessarily a bad thing, I would expect violinists to find it "different"... which is usually not so attractive in the violin world.  But the low frequencies are just a small part of the spectrum, and the rest might be good.  Do you find that the low E string has some loud notes that might be due to the peaks in the 700 - 800 Hz range?

indeed. The G string lacks definitively violin character. I think I know what went wrong.

Here are the next graphs after correcting the bass bar grid. i added stiffness to the cross bars which run approximately along the nodal lines of mode 5 (ring mode) by adding 5mm height.

The result when playing was directly much better and especially the G string gained character. 

Here are again the graphs in low resolution and high resolution:　

(comes closer to your Strad sample）

 

 

[baroquecello]

So how does it sound when strung as a viola? Is this a good concept for a small viola maybe?

[Andreas Preuss]

12 minutes ago, baroquecello said:

So how does it sound when string as a viola? Is this a good concert for a small viola maybe?

I never strung it up as a viola because the string length wouldn’t be long enough for viola strings. But actually I think some of the construction principles of the New Concept Violin can be used successfully to build good sounding small violas maybe as small as 39-40cm. The off center string axis could also help enormously to make the playing in very high positions much more comfortable. Before I am heading to such an adventure I want to finalize the New Concept Violin. 

[Andreas Preuss]

Continuing the sound calibration

 

In the past days I reworked the reinforcement grid. Based on my previous assumption that increasing the cross stiffness there will be an improvement in the ‘soprano quality’ I renewed the spruce reinforcements. I cut them off and replaced them with stiffer bamboo and also increased the height from 5mm to 8mm.

I also added a third short curved bar in the center because I could see that despite the bracing the top would slightly deform in that area under string tension.

 

The first impression confirmed my hypothesis that added cross stiffness improves the soprano character of the sound. However, in the initial setup the sound felt a bit ‘narrow’, and ‘tight’. This could be corrected with a better setup where I am playing with string angle (with a higher or lower lower saddle) sound post position and bridge position in all four directions. (This means that the stop length on the top is for me not a sacrosanct 195mm)

 

Here are two representative response curves which also demonstrate what can be done with setup.

 

The first sample is what I would regard as the most balanced setup. It can be literally seen in the picture of the graph in low resolution. Low frequencies are not too high in comparison to high frequencies and nowhere are deep valleys. That corresponds pretty much to how one would describe the sound, full, rich and even over all the strings, in particu;ar there is no major weakness on the higher positions on the d string which can be at times problematic. For my personal taste there could be a little more texture, right now I would describe the sound color more like ‘smokey’.

In the second graph I have taken I managed to bring out more high frequencies between 3kHz and 4kHz which made the sound slightly sharper but would also require a little bit heavier bow arm. More on that in my comments on bowing and what you see in the response curve.

Since a while I am taking all graphs by playing a half note scale on all 4 strings 4  times. Each time I make a 90degree turn to the left so that I am standing with my back to the microphone on the third recording. Here is one additional graph from the best adjustment where I cut out the recording where I am facing the microphone:

 

Until now I didn’t think much about bowing but I made (at least for this instrument) a few interesting observations:

 

1.      fast bow speed actually can to a certain degree force more overtones in the 3-4KHz region.

2.      a heavier bowarm (like leaning into the strings) makes a somehow broader sound but does NOT change anything in the area of 3-4kHz. The broader sound can be seen as ‘more mass’ in the lower part of the spectrum.

3.      Don’t forget to put rosin on the bow.

 

So when looking at the spectrum in the region of 3-4kHz (which is IMO the part in the spectrum which is most difficult to influence in the setup) attention must be paid to the bowing when taking the graph. If we had many high responses this would probably diminish the possibilities a skilled player can mould the sound to his her own ideas in a given piece of music.

 

 

Because the sound got now to a level where I am actually 95percent satisfied I also looked more into the possibilities a player can achieve with different bowings in terms of speed pressure and location on the string.

[Andreas Preuss]

Final (?) sound result.

I think I arrived at a point where I cant improve the sound much more. So here I want to show first what came out and further down I added some hopefully interesting explanations to it.

The differences here seem to be not so big to the previous graph, but when playing the instrument there was a distinctive difference. The sound became sharper more textured with a high frequency sizzle. Or for another verbal discription the sound is rich and vibrant. So basically 98 percent of what I was looking for. (My adrenaline goes high when i get a texture with a certain coarse roughness)

However, on a closer look there are some minor differences which make a difference. First I could raise the two peaks at 3650 Hz and 3900 Hz to a higher level (red arrows). This created (to my understanding) more edge in the sound. Frequencies up to 7500 hz seem to be responsible for the high pitch sizzle.

The Dunnwald dip is around 1050Hz and not too deep and not too wide which seems to be good because the bridge hill spans from around 1450 Hz to 3100 Hz and if we 'ignore' the dip at 3400Hz, it extends to 3900Hz. I think it is also good to have two peaks there to cover a broader range of overtones for the single notes played.

Comparing the average level of the low frequency band with the average of the bridge hill, there was also an increase for the bridge hill. Before it was around 9dB difference to the average of low frequencies', now it is at a pessimistic estimate around 7.5dB difference. (maybe only 6dB)

I still couldn't figure out what creates the dip at 3400hz. If it is related to the architecture of the bracing on the top i will find it out sooner or later. Now I have not the time to look for it any further. 

So overall the sound is definitely better than before. I should also mention that playing the instrument there is a good balance between strings and nowhere notes are sticking out. It’ｓ a bit harder to play than before, that means if I lose focus on the weight of the bow arm a note might squeak. 

In total I wouldn't say that there is a major problem with the bracing on the top, but the last word on that have players who will test the instrument soon.

So here is what I made in order to achieve this improvement in overtones. so far i focused on the top plate and somehow I hit a wall where I couldnt trigger anything above 3KHz. So I decided to look once more at the back. At 73g it is certainly below any normal standards. My guess was, that if the back vibrates at frequencies above 3000 Hz it will probably diminish the same vibrations on the top absorbing energy which is needed there. therefore i tried to prevent high pitched vibrations on the back with well placed bracings. Following the ideas of @christian bayon I glued 3mm bamboo strips from the top block area to the upper corners and additionally I tought it might be good to stabilize the center at the sound post. There I layered three sheets of .5 airplane plywood at the width of 30mm from one side to the other basically touching the ribs on both sides. 

For those interested here is also the high resolution graph.

General data:

total weight: 320g

string angle: 158

bridge height: 30mm

bridge weight: 1.4g

strings: Jagar superior except A string (Evah Pirazzi medium)

Sound post position 2mm behind bridge, 3mm inside (I realized that the post coming too close and too far outside always lowered the two peaks at 3.65 and 3.9khz)

 

 

[christian bayon]

Like that?

[Andreas Preuss]

1 hour ago, christian bayon said:

Like that?

I solved this like this