A website for the serious amateur violin maker, restorer and tinkerer. A violin front and back (the plates) can be tuned using tap-tones. Use tap tones to adjust the 2 plates of a violin to get the best sound, the kind of sound you want, or make an instrument that is easy to bow.

This site can help if you are making a violin or you want to improve  a low cost violin or viola.

By tuning the top & back plates you can be confident that you will get a good instrument that responds well to the bow and that can sound like a $1500 instrument.

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All you can ATE!

 A is for Arching,

   T  is for Tap-tones, &

      E  is for Edge-work.


‘Harrison’ Stradivarius violin plate thicknesses

email: webmaster @platetuning.org

 Last updated:                                 20 th. May. 2017                    Copyright  (C)                www.platetuning.org


 Patrick Kreit’s book.

     I did develop an theory over the last few years based on combining Dr. Harris’ and Carleen Hutchins’ work, but it dawned on me months ago that the significance of plate weight at the heart of Dr. Harris’ idea of plate stiffness figure mentioned above is easily tested.

   I just needed to make 4 similar (ideally identical) violins:-

   1) with a heavy front and heavy back plate,

   2) with a heavy front and light back,

   3) with a light front    and heavy back, and finally 

   4) with a light front    and light back plates,

                 and then see what the differences are.

    The criteria for the quality of the resulting violins would be based on

  a) where the key 6 resonances below 600 Hz fall, and

  b) what the 2 violins are like to play: their tone and response under the bowTap Tones 1.

    Fortunately, with practice, the key body resonances are quick and easy to measure, and if the weight of each plate really is a significant factor then the violin with heavy plates would probably turn out to have low key body resonances, in particular B1- and B1+.


   For 1), with heavy back and heavy front (belly) I found that taking an old Maidstone Strad-model violin to pieces and reassembling it (in fact with a new maple back I made) showed that the weight of the belly and back plates has almost no measurable effect on any of the key body resonances.

              Most importantly, B1- and B1+ resonances. The belly is 17 to 20 grams too heavy (at 82 grams), and the back 25 to 30 grams too heavy (at 127 grams) and when belly and back are heavy only the Mode 5 and Mode 2 plate frequencies mattered. The Maidstone, originally a very cheap violin for beginner students dating from about the year 1900, now plays very well and easily and with good tone, especially on the A and G strings. Details of all the parts and final body resonances can be found here as a .pdf page using the format laid out below.

   2) For a violin with a heavy front and light back I had mended and tuned the plates on an old Hopf copy from about 1820, which gave very good results - but it isn’t Strad. model of course! 

   3) I have yet to find a violin with a light front and heavy back to work on, so there is still plenty of work to do........... and for ....

   4), a good quality violin with light plates?

        Well fortunately,  Patrick Kreit (on the right in the photo below) has published “The Sound of Stradivari”.
Patrick Kreit 4

      I came across his violin-making book (costing € 485 now). Mr. Kreit links the Mode 5 frequencies of the violin's  plates to the resonant modes of the final violin body, step by step. He has done 20+ years work in exploring the relationships between violin plate's resonances (with Mode 2 set to half Mode 5) and the 6 key body resonances: see the ‘Resonances of the Violin body’ page. He has found a method for consistently getting the lightest possible plates .... so I did not need to make a Strad-model violin with very low plate weights to compare it with: all the data is in his book.

    The profound limitations to Dr. Harris’ work have shown up too in Jo Curtin’s work, published in The Strad Journal: see this page and revealed by his his article on Strads. The effects of gluing each plate to the stiff bouts seems to dominate!

Simple theory

   As I said, I have concentrated on getting the tap tones of the plates where I want them, but tap-tones are just a part of the whole: the air volume, f-hole area, arching, body length, sound-post and bridge must all be right too.

  My findings so far are that Carleen Hutchins broadly got it right: if you set the Mode 5 tap tone of front and back with the belly just a few Hz below the back  at 340 to 350 Hz (measured with low moisture content in the wood), your fiddle can turn out sounding good!

  To get more consistent results, especially helpful for beginners, the other change to traditional practice the Mr. Kreit introduces is measuring and setting what he calls the Coupling Frequencies.

  There are  two Coupling Frequencies are the tap tones or resonant frequencies measured when

    1) just the back plate is glued onto the bouts (or garland) and without the neck attached,      and then HoVBRs-Rd V1.0 smll

    2) just the belly is glued onto the the bouts (or garland)., again without the neck.

        These are easily and quickly measured, but do require that one of the plates is first temporarily glued (using diluted weak glue and cigarette papers!) to the bouts or garland, and then removed before the other plate is glued to the garland.

     This puts an important intermediate step between setting the tap tones of the pates and then setting the difference between the coupling frequencies of back and belly to about 25 Hz, as shown in the important chart on the right. Click on it - it is a .pdf file.

    This makes very important  violin body resonant mode frequencies much more HoVBRs-Rd wksheet smllpredictable

    So for a violin made from scratch, that is started from blocks of wood, I can measure the 19 different frequencies of the individual parts and then also the final body-mode frequencies of finished violin. So the instrument ends up with the key body resonances just where I want them.

    The chart I use to do this now for all my violins is here on the right - click on it: it is important.

Plate weight

   Does it matter if violin plates are heavy even though they are tuned to the right Mode 2 and 5 resonant (tap tone) frequencies?

    Well, yes it does, and a lot. The weight, or rather the lightness of each plate is a measure of its quality, providing that it has the right tap tones and low losses when it vibrates. A light plate with the right arching and thicknessing on good wood has less wood for the bow and strings to move: it will respond more quickly and give out more sound energy.

   If you have a look at the page on ‘Plate tuning 4 dummies’ I show you how to make the best of the wood or plates you have to make a violin that will sound very good indeed, but there is no substitute for buying the best low density stiff wood you can afford! 

   ‘Ordinary’ wood will make a good violin (as the Chinese student violins now show!) provided you get the plate tap tones right!