Sign in to follow this  

Tap tone for finished cello back

Recommended Posts

I have found an article by Nigel Harris, "On graduating the thickness of violin plates to achieve tonal repeatability". Here are the frequencies (for cellos):


-back mode #5 -  142 Hz (C#-D)

-back mode #2 -  66 Hz ( C)

-back weight - 673 g (low 630, high 716)


"... resonance frequencies averaged over about 150 instruments made in our workshop to the thickness graduation method given in this paper".


I have made recently a 140 Hz for #5 and 53 Hz for #2; the wood was very heavy, so the finished back was outside Harris' reference data for his cello back. 


I would like to know opinions about this article and method, thanks!



Share this post

Link to post
Share on other sites

Thanks for the responses, but I am totally in the dark when it comes to modes.  I hold the plate between thumb and finger in the upper left and tap in the lower right and seem to get an F tone.  Does that mean anything or am I just tapping in the wind.  It seem to have a nice ring to it anyway.  This is my first cello attempt and as hard as carving this back was it will probably be my only.

Share this post

Link to post
Share on other sites

Hi,  I wanted to check this thread again but I didn't have time this week.


This has helped me in finding the resonant frequencies: since the nodal lines in cellos are obviously farther from the borders I have tried to use a deep-throat clamp (the ones for gluing the bassbar) and small pieces of soft rubber, to support the back. Then I also made a small "hammer" with an eraser, covered with felt (taken from an old blackboard eraser). The eraser was tied to a thin rod.

Anyway, I have tried to stay near the figures in a "standard" thicknessing diagram (ex.: Henry Strobel), and I noted down the frequencies for future reference. I definitely need to make more instruments and experiment with different woods.

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.