A website for the serious amateur violin maker, restorer and tinkerer. A violin's front and back can be tuned using tap-tones. Measure the tap tones and plate weights and adjust them 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 and weighing the top & back plates be confident that you will get a really good instrument that responds well and can sound like a $1500 instrument.

Like the best coffee ...  LATTE!

tapping belly 2 sml

Light-weight plates, &

  A is for Arching,

   TT is for Tap-tones, &

      E  is for Edge-work.

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Violin plate Modes and Weights 1.1 smll

email: webmaster @platetuning.org

 Last updated:

1st.. Jan. 2021

Copyright  (C)



What is new on this site?

  This site available in all the major world languages here at Google translation in  FrenchSpanishGerman or Greek   ....

So, what is this site for?stradivarius

   This site is for people who are making a violin or viola, and also those people who want to modify a low-cost and poor-sounding instrument to dramatically improve its tone and playability.

          I’m not trying to sell you anything here, (although there is a small charge if you want to download the full set of Dom Excell’s articles on “ Making a Successful First Violin”).  There are no ads or malware. Really.

       I believe strongly in the ‘Wiki’ idea: I feel a need to communicate what I know, so that’s what I want to do for other amateurs and any professionalos who want to know of plate tuning.  What I ask  is to hear your story, so contact me at webmaster@platetuning.org and let me know what you’ve learned in fiddle making!

parts of a violin - HansiThe parts of a violin

     Firstly, what are the parts making up a violin?  Have a look at Hans Johannsson’s site: there’s good stuff there on the construction of a violin.  You can see the front and back ‘plates’ in his diagram left - click on it.

     I have scanned in (with OCR to searchable .pdf) all 24 articles published 20 years ago in THE WOODWORKER magazine (UK) on ‘Building your first violin - successfully from scratch!’.  It was written mostly by a trained violin maker, Dominic Excell.

   The first 6 of the 24 articles are available for free here: the last 18 of the 24 are password protected - they are all in .pdf form and can be printed off as needs be. The passwords cost £10 UK (15$ US) - so get in touch with at webmaster@platetuning.org  if you want to have them. There are also several good books too an making a violin: have a look at my ‘Books’ page too.

  These 24 excellent articles by Dominic talk you through all of the basics of starting what is a daunting project ... and indeed do not address tap tones at all, but then maybe that's the way for you to start your Opus 1, your first instrument!

Tap Tones for the front and the back of violins.

    The two pieces of wood that make up he front and the back of a violin are called ‘plates’, as seen above.

    If you open up a violin, or if you are making one from blocks of wood, you can change (almost always just reduce) the tap-tone or resonant or ringing tones or frequencies of these plates using a tiny thumb-plane and a scraper by removing wood from them. You can easily measure these tap tone frequencies for free as you work on the plates by using a microphone and your home computer, tablet (or even your feature phone!) so that the violin (or viola) will sound really good.

   As well as thumb plane and scraper you’ll need some kitchen scales and a thickness gauge to measure how thick the wood is all over. You can then be confident that your first violin or your second or your tenth will sound excellent!  Or perhaps you could also improve the tone quality of low-cost, poor sounding violins as I like to do!

  This isn't my work really. It's using, summarising and building on the years of work many others, what the great names have done over the last 60+ years. I have no problem with standing on the shoulders of others. I'm an experimental researcher by inclination and training: so ‘try it!’ I say. And I love reading and learning what others have written and I hope you benefit.Grail

Good tone: the search for the holy grail.

    At the heart of getting good tone from a violin is good arching and using the tap tones of front and back plates to set the sound of a violin where you want it.. The plates’ tap tones are a measure of the key properties of the wood and arching of the plates. What tap tones do is show up the quality of the wood itself, especially the spruce of the front or belly. So don't just use any old wood. Use good old wood.

  By setting these tap tones to chosen frequencies, as well as taking into account their weights, almost any factory violin can have its tone dramatically improved, whatever wood it is made from. Have a look at the example violins (and violas) on the ‘Violin viola examples’ ref. page.   For interest I have also included pictures of what the best makers did over 300 years ago with some pictures of the outstanding instruments at the Ashmolean Museum, Oxford, UK. Do see them in person if you can.

The tap-tone method outlined on this website allows you to choose the tone you get too. It could be a ‘student’ tone for easier bowing, or perhaps you want a ‘solo’ instrument tone with harder bowing, but very powerful, and suited to real solo work. My personal preference is for ‘chamber’ and ‘orchestral’ tone instruments midway between the two: easy to bow, and flexible in use, suited to an Irish pub session, a quartet or in a symphony orchestra.

   The key to this choice of tones lies in the key violin body resonances or modes, and there's more details on those modes on this page, but that is definitely running before we can crawl. Get the plate tap tones right and the assembled body resonances, with some skill and craftsmanship, come out right!

Limitations: you need craftsmanship too

   This however is not a cure to all human suffering. Much or most of a violin's quality of sound derives from just ‘good practice’ in its making. There is no substitute for proper, patient, practiced craftsmanship and artistry in the making and modification of an instrument. It should be, it must be a work of art!  I cannot begin to teach any of that. I can only help you with some of the science and engineering aspects. Go to a craftsman for craftsmanship, and set aside some years to do it.

Tuning the plates

   Plate tuning can help make your first or your fiftieth violin a good instrument - a fine reward for tens of hours of work. And it is not at all difficult. I personally mostly use this method to improve the tone and playability of factory-made, damaged, early 19th Century violins, old school and auction violins, many with bad sound-post cracks.

  Significantly, I have found a way of quickly measuring Mode 2 and Mode 5 frequencies of violin backs and the back’s weight, without removing the back from the neck and the bouts (the sides and blocks). This is outlined on the page here.  Using a short, very thin knife and warm isopropyl alcohol  mixed 1-to-1  I remove only the front (belly) and fingerboard to measure and work on the inside of the back to set up the back’s tap tones (Modes 2 and 5) and Mode 5 (ring) tone. Then I modify the belly plate to match it.

      If a back is good and with specially resonant tap tones, carving a brand new spruce front can also give you remarkable results: but you have to start with good seasoned spruce for the belly though!

Arching and thicknesses

  If you want to know what arching and thicknesses to use for the plates, have a look at this page.

    I have included 2 figures that show how to thin plates to get Modes 2 and 5 where you want them. This data is from  Acoustics for Violin Makers by Erik Jansson in  “Chapter V: Vibration Properties of the Wood and Tuning of Violin Plates”, and here is just  page 25 extracted from it, with a scheme to gradually reduce thicknesses of plates while keeping Modes 2 and 5 under control. This series of papers by Erik Jansson is a key reference work on acoustics and the violin: and it’s free!  He used to work with Carleen Hutchins (CAS) and really knows his stuff.   Have a look on the links page too.

    If I had to name priorities in making a violin I would say ‘I like my coffee as a   “L. A.TT.E.” :-

  • ‘L’ stands for light-weight plates.
  • ‘A’ stands for arching:  it has to be right!
  • ‘TT’ stands for Tap-tones, so the violin will sound good, and
  • ‘E’ stands for Edge-work. Tap-tones do not measure the way the edges are cut, so the channeling and edge thickness - how it becomes the rising arch of the plate.

History: let’s start at the beginning

     Every journey begins with but a single step, and every organisation begins with a single member. That's me. My committee meetings always run without a hitch.

   I’ve always wanted a Stradivarius or Guarnerius violin, but somehow I can’t seem to find that first £ million. I played a Guarnerius violin once, and it spoiled me: how could I, that bowing arm be making that fabulous sound? That sound, that's a bit like a professional soloist on a CD?  Well, with all the arrogance I could muster as a qualified engineer, I decided if I couldn't buy one, I’d have to make one. And of course, I know that as soon as I get a Stradivarius then my amateur scratchings will be instantly transformed into something truly wonderful ......

     I am now retired, with violin repair and violin making as a (fanatical) hobby.  I can spend time building and rebuilding violins and violas as experiments to test out ‘plate tuning theories’ as the fancy takes me. I have no commercial interests, and that gives me a big advantage: a fiddle shop just cannot afford to do that!

A rationale, and Carleen M Hutchins.

    Over the years, while trying to make some awful violins sound better, I needed a rationale to this mending and tinkering. My long-suffering wife bought me the collected works of the CAS (Catgut Acoustical Society) for Christmas 10 years ago.           [continued in next column .....]

     A remarkably lady,Carleen Maley Hutchins Carleen Maley Hutchins (photo right) co-founded this Catgut Acoustical Society (CAS) nearly 50 years ago, and I remember her first article well: my mum showed it to me in the early 60’s when it was printed in Scientific American , Nov 1962. You may be able to get back-copies if you do a web search.  A later article by her in 1981 could be found on a Russian website and the which I’ve put into a .pdf file here. The excitement of that approach stayed with me. Carleen died in Aug ‘09 at the grand age of 98, and her obituary was published in the LA Times.

     There is a moving video on youtube of her talking about violins, violas and wTap Tones 1hat she did, and here is an interview with her too.  What a lady!

    Traditionally, violin makers ‘tune’ the front and back plates around an ‘F’ to ‘F sharp’ tap tone**. Tap-tone methods has been around for well over a hundred years (see footnote) and probably very much longer. Unfortunately factory-made fiddles, all that many of us can afford, have never even heard of ‘tap tones’ or even suffered much care in manufacture. Indeed many of these fiddles have so much wood in the back that if burned they could heat a small home for an evening.

  The best article on the web I have found is a one by Alan Carruth dating from 1992. It pre-dates the home computing revolution, but he was trained by Carleen Hutchins and has a gift for writing, so have a look at this article called “Free Plate Tuning: Part II, Violins”.

Quick & free frequency measurements with a smart-phone or a home computerComputer_of_the_Future_1954-2004

     What has changed over the last 10 or 20 years is that the home computer (+ mic.) - and recently the smart-phone have made available to us methods for measuring tap tone and violin body resonance frequencies very, very quickly - and for no cost.

     You can use your smart phone with the right app such as AudioTool, Spectroid, or Audizr, or Spectrum RTA: there are over a dozen free Audio Analyser [FFT] apps avsmartphone image 1ailable to do it!  It takes me a minute or so to measure the tap tones of a violin plate: it is particularly quick to use a smart-phone. You just put it on a desk edge with microphone outwards, set the “Max. hold” function and and tap the violin plate near it - and that’s it.

  Carleen Hutchins would need perhaps an hour or more with specialist equipment, and Signor Antonio Stradivari? Well, he needed a very well trained ear and maybe a a ‘standard’ wooden rod or mono-cord to tap for comparison.  A good ear helps, but is not essential.

   At first I found that Carleen’s methods of adjusting the tap tones of front and back to an octave (2:1 ratio of Modes 5 and 2 frequencies in both) did not seem to always produce really good fiddles: but they sounded better than before.

   I think it's because the wood for factory fiddles, especially the fronts, is not good, low density, prime-choice wood and you have to strip the violin right down to its parts!

      Makers can pay as much for the wood as some people might pay for a violin outfit.  Try Lemuel Violins (formerly Luscombe Violins Inc) for wood: a family-owned retail business in Mt. Elgin, Ontario, Canada, or  Touchstone Tonewoods in the UK.

    Simeon Chambers  (in Colorado, USA) has an excellent  range of wood at reasonable prices and plate thickness maps for sale too. He suggests the light Englemann spruce for bellies, with a density (specific gravity) of 0.34 to 0.38 gm./cc., which is much less than than normal European spruce at 0.45, but European makers often prefer Bosnian Spruce. He also recommends, and many makers  insist that the back plate maple has a density no more than 0.6 (gm.per cc).  0.65 gm per cc. is normal. It needs to be light and strong! Simeon has alas stopped cutting this top-grade wood now (early 2017), but there are some items left.

Main violin body resonances: key to good tone.

       To get a violin to sound good you need to get the 6 key body resonances below 600 Hz in the right place and these resonances need to be in ‘harmony’ with each other.

  1) The air inside the instrument resonates through the f-holes, so it has to the right internal air volume and the f-holes need to be the right size or area. This gives strength to the G-string’s sound. (This is the Helmholtz resonance)

  2) The air column along the length between the end blocks resonates rather like a church organ, so the body needs to be the right length,

  3)  the arching and channel around the violin needs to be the right shape, and

  4) the tap tones or speed of sound along and across the top (belly) and back plates needs to be within tight limits.  These give strength and quality to the A-string's sound.

  5) The plates need to be as light as you can make them for sound volume - but with tap tones not too low (see 4) above.

  6) the bridge and sound-post must be fitted correctly so the violin talks, and so the higher frequencies, all of  them, and there are lot above 600 Hz, can come out.

          There is an awful lot to get right.


History: ways of making a violin

       In making or modifying a violin or viola for good or better tone you can choose one of a number of methods. These are, in historical sequence:-

  •   Use craftsmanship! Get help, get trained, get experience, and make your first dozen violins. There is no substitute for knowledge, craftsmanship and for experience, not least in choosing your wood.
  •   There are many plate thickness maps available, and there are some available free on the web. They kind of work, but most plates need to be thicker or thinner than the map, as every bit of wood has different elasticity so I recommend ‘tuning the plates’ too! Dominic Excell’s articles on a First Violin does not use plate tuning (but I’m talking to him!).
  •   If you do choose to use wood tap-tone tuning methods, then adjust the traditional Tune Mode 5 (Ring tone) with the back Mode 5 sounding F#, and the front at F as a ‘raw’ plate before f-holes are cut. This ‘F’ later becomes  F# and even G with f-holes, bassbar fitted and varnished . The tap tone must be a full, true ring, the best you can get. Mode 2 frequency ‘floats’, and the plate’s weight is ignored. Typically, allied with good practice, very good wood and experience it works well**.
  •    use the ‘CAS’ method: Tune Mode 5 and Mode 2 to be an octave apart (Mode 5 = 2 x Mode 2). This is Carleen Maley Hutchins’ (or the CAS***) method. It works well if you are choosing the best wood.  Modes 2 & 5 frequencies of front and back should be equal.
  • Dr. Nigel Harris’s came up with a method Tune Modes 5 and Mode 2 and take the violin plate’s weight into account by making the ‘plate stiffness’ proportional to the plate’s weight. Dr. Harris may achieve tonal repeatability using his ‘stiffness’ method but my data shows that heavy plates need to be made with significantly higher not lower tap tones!
    • I did suggest using his ‘stiffness figure’ method for years on this site. I apologise profusely to anyone who used it, it is simply wrong and unnecessary.
  • An excellent book by Patrick Kreit “The Sound of Stradivari” was published in 2011.  Dr.Harris’ work on plate Stiffnesses is not compatible with Patrick Kreit’s work. I have found that light plates are much better, and so far as I know Patrick’s book explains the only method to produce the lightest plate from any given piece of wood.

 Theory: Dr. Nigel Harris and Patrick Kreit

   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.  

   About five years ago I came across Dr. Nigel Harrisan article by Dr. Nigel Harris (interviewed here!)  that seemed to be the next step in the elusive connection between the tap tones of a violin's plates, its playability (the violin's ease of bowing), and a real quality and depth of tone. In addition, as  Dr. Harris puts it, it can make a given tone reproducible, violin to violin.

   Dr. Harris (right) who sells some seriously good, pricey violins at Harris & Sheldon (violin.co.uk)  links the plates’ Mode 5 (called the ring tone),   Mode 2 (the ‘X’ Mode), and the weight of the plates into what he calls each plates’ ‘Stiffness Figure’. His work on 1000 + violins and his rather complex theory shows that if the front and backs have a similar ‘stiffness’ then a good fiddle can result.

  Patrick Kreit’s book “The Sound of Stradivari” has been a revelation on how the violin plates’ tap tones are linked directly to the finished violin body's key body resonances, the ones that make it work well as a violin!

 So I have built on the work of Carleen Hutchins, Dr. Harris and Patrick Kreit to provided a theoretical (or perhaps empirical) framework and route to show you can make excellent-sounding violin, that is to made the construction of a fine first violin a real possibility.

Make it as simple as possible.

    I have modified, simplified and explained how to do it here, and provided the ‘tools’ to do it: my objective is that apart from using a computer or smart-phone, a ruler and some kitchen scales to measure a violin's parts as you go along, you should not need a calculator. So I have provided charts and tables to do it.

Quick results: Plate Tuning for Dummies!

    On my page called  “Plate Tuning 4 Dummies” there is the information for those people who want quick results and rules of thumb to make a good fiddle first time round, but you really need to check and adjust the tap tones and measure the weights of the partly assembled  and even the fully assembled instrument to get a really good one. There are no short cuts, because every piece of wood is different.

     I have 8 or 10 beautiful, well-made violins by amateurs that look really wonderful on the outside, but play like the cheap school fiddles - simply because they did not have their plates tuned at all!

   So have a a glance here for the basics: but you will still need to know how to hear and or record a tap tone on the “ Mode & tuning plates” page of course!

What this is all about? Make a $150 violin sound like a $1500 violin

 So this web site is all about just how to measure tap tones and weights to help you make a new violin, or to modify an existing and poor-sounding $100 factory fiddle to get it to play and sound like a $1500 violin.

  So have a look at the various pages here. In particular, have a look at how to easily measure tap tones.  I’ll show too the various stages of how I modified some poorly made instruments as examples. You can’t do much damage to a £40 ($60) violin: at worst it’s £40 of experience. But Warning: but do not do this on your Concert Stradivarius!

Feedback: tell me what you think, and tell me your experiences.

   Let me know what you think of this site and its contents: violin plate tuning seems to evoke strong emotions in luthiers ...... so email me now at webmaster@platetuning.org  !   It’s all work in progress, so I’ll include your comments, but no promises though.


    Footnote  ** :       F#  is 370 Hz, F (natural) is 349.2 Hz, and E is 329.6 Hz.   The reference here is to Ed. Heron-Allen’s book on violin making of 1885-6. Believe it or not he refers to Modes 2 and 5 and ‘nodal lines’ on p.133, and tells the reader how to make them visible  using sand and a bow!   Yes, that's from 125 years ago.

   Footnote 1)  Many authors (Hutchins, Molin, Moral, Schleske) use the terms “eigenmodes” or eigenfrequencies”: they are just body resonances of the violin corpus, in part or finished state.

   Footnote 2):  In particular the B1-, B1+ and CBR body resonances. Since the two coupling frequencies are present on the finished violin, they are in fact “eigenmodes” or “eigenfrequencies” 1 of the whole, finished violin.  So thay can be adjusted or set at the intermediate stage during the building of a violin, i.e. with just one plate at a time glued to the bouts or garland.    The two Coupling frequencies then control and set the key B1-, B1+ and the CBR (C2) body resonances. See also the page Resonances of the Violin body.