Davide Sora

It is. Probably more than mineral spirit (petroleum). Both are not fresh water.

The grip points "P" and the listening points "A" (where to tap and place the mic) can also be different, as long as the former are placed along the nodal lines of the mode, and the latter in the antinodal area of greatest movement. Sometimes it can be useful to move the grip point to isolate a single mode, avoiding the crossing points with the nodal lines of the other modes, to avoid as much as possible multiple resonances (more modes vibrating at the same time), or at least make sure that the resonance we are interested in detecting is stronger than the others.

The "noises" of life look good in videos, they give the feeling of being in the workshop while watching.

In my Audacity graph, in addition to the PC fan that doesn't work very well and the heating, there are also cars passing by on the street. If you want, you can remove the noise by applying a high-pass filter with a threshold just above those frequencies, you can find it in the effects section of Audacity. I don't do that, just know what's in the graphs and what to take.

Cello plates center joints, the beginner's nightmare. It's been many years since I made a cello, and I confess I was a little worried too. Fortunately, everything went smoothly and they came out perfect. This time I put the English translation of the texts in the comments section, not in the description page. I hope it will be easier to find and consult this way.

Yep, now the peaks of M5 at 368 Hz and M2 at around 130 Hz are definitely higher than the rest, apart from the left side of the graph which is background noise.

I suggest you use a more detailed size, 4096 or even 8192, which are more suitable to better highlight the low-frequency peaks. They will become narrower and more pointed and will be more readable.

Thanks for your reply. On some del Gesù you can see some pinpricks on the edge of the f-holes, which could be interpreted as the vestiges of a tracing on the outside. I believe Hargrave mentioned this in his work on the construction method. I believe that Stradivari also took the center line into account to place the upper eyes. In fact, starting from his original drawings for the placement of the f-holes, it is clear that the measurement of the distance of the centers of the upper holes from the ribs had to be changed due to the difference between a 2D drawing and a 3D arching, and in my opinion in this phase he made corrections to keep the upper eyes reasonably centered with the center of the violin since their position is important for centering the neck and the bridge. I am not convinced that the Amatis used a different system from Stradivari (the system of circles that you mention), in fact inside some Amatis you can see the two parallel lines for the placement of the lower eyes and some pinpricks left by the compass on the line of the ribs, which would indicate a similarity (at least partial) with Stradivari's method

Give us feedback, curiosity is killing me.

Does yogurt form a hard film when dry? It might work in this case, but I suggest testing on plastic sheets and wood scraps before putting it on the violin.

Hi Advocatus Diaboli, that's an interesting point. May I ask if you have found any particular evidence of this on the original violins, such as tracing marks, or what other evidence makes you think so?

Despiau and Milo Stamm make bridges of all sizes. However, to make a 41 mm wide bridge I prefer to start from a 42 mm bridge and reduce it (I plane the sides with the blockplane, if you want you can see how I do in my videos), to keep the ankles more spaced apart

I agree with you, I bet the glue was way too diluted.

I second this, and perhaps try to make a structure that deforms as little as possible. Some archings are more deformable than others longitudinally, especially when they have the sixth with a very long straight section and very steep curves concentrated at the ends, like those frequently seen on the top of some old instruments