Thankyou very much, from an aging, Kiwi, part time hobby luthier. You have vastly greater experience, knowledge and facilities than I do. But I enjoy experimenting with the unknown. We are on the same page. I have found all the vids of yours , that I have so far viewed. Extremely helpful and thought provoking. Once again, thanks so much.

@chuckmorrison

11 ай бұрын

Thanks Murray, I'm glad that you have benefitted from my work. I've always wanted to spend some time in NZ, and hope to make it some day. Till then I'll just cheer on the All Blacks.

@murraykilpatrick3029

11 ай бұрын

@@chuckmorrison keep my contact . If you ever do get to swim the ditch. We have a big house with a spare bedroom. Oh and I have a very messy workshop..

@chuckmorrison

11 ай бұрын

I will definitely keep it in mind. Thanks

I particularly like the philosophical lesson you present at the end.

Great video dada, I appreciate the time and effort you took to try and analyse the doming of a soundboard . I use a jig that applies a 40 kg load at the bridge.. i keep tap tuning and thinning until the top just begins to deflect at load.. Your videos require multiple viewings to understand your point of view but in the end it does make sense

The wood is under compression something which is not the case in a guitar. The top radius on a guitar is under a slight tension if not passive. What the arch in a guitar top does is contribute to resisting downward pressure. The nearest analogy is the arch of a bridge. Plus it gets rid of the curious effect of a flat surface looking concave.

@chuckmorrison

10 ай бұрын

You are correct, although the response of the top is to arch upwards to relieve that compressive force, as opposed to just compressing the cells. This was a simple experiment to see if the tap tone changed much in this situation, which as you say, is not exactly what is going on in a guitar top.

Really good demo! Btw, nice looking desktop. What are you running there? Linux on KDE or Gnome? Something else?

@chuckmorrison

Жыл бұрын

Ubuntu Studio. KDE plasma.

wow nice experiment chuck would the top being in tension cause the higher frequency .luthier a science with to many variables to pin it down very interesting

@chuckmorrison

Жыл бұрын

On a solid wood top, yes, although it depends on how to build the top. There are more variables than just the arch at play.

Is this emulating the 15' radius in a flat top style guitar? And of course I realize it was exaggerated. It would be different in a carved arch Right? With no tension.

@chuckmorrison

Жыл бұрын

Well, not that specific radius for this experiment. As you can see I just cranked on the vise and eyeballed it. I did it a few more times just to see what would happen as the pressure increased. I'm also only forcing the arch along the grain, a true spherical contour would be equal pressure all the way around and bracing would contribute to the contour as well. Yes, a carved top is not bent like this, so this would not apply. It would also not apply for "double top" soundboards that are formed to the contour or "arch top" (F hole) guitars that have pressed plywood tops/backs.

@jonahguitarguy

Жыл бұрын

@@chuckmorrisonthanks Chuck, I appreciate your time and answer.

@hampshirepiano6383

Жыл бұрын

Yes.

@hampshirepiano6383

Жыл бұрын

Just to say, piano SB's are forced into a curve. Increasing the stiffness without increasing mass! The same theory applies to flat top guitars. Bridge rotational force bends the top = bloom in the room!!!

So is that graph you show a Fourier transform of the recording?

@chuckmorrison

10 ай бұрын

Yes

It seems the data would have been much more useful if the arched wood was not under tension.

@chuckmorrison

10 ай бұрын

The only way I know to get the arched profile without inducing tension is to steam bend the wood, which I don't do and actually is just a way of preserving the shape of a pre-tensioned piece. Carving would not be equivalent in any way, requiring different pieces of wood. The reason I used this method was that it was the same piece of wood in both cases (relaxed and arched) and I actually do arch the soundboard over the sides when I build a solid top guitar.

@larryhawes8295

10 ай бұрын

And yes a guitar top when arched as most are in modern guitar building I would agree they are also under tension as your experiment shows. I stand corrected.

This information is misleading.

@chuckmorrison

Жыл бұрын

Please elaborate. Did you watch the video all the way through ?

@AndSendMe

Жыл бұрын

It is misleading to say that the facts presented in this video are misleading, particularly with no context or foundation.