Tap Tone Part II

April 11, 2007 at 6:40 AM

I am reading "Strativari's Genius" by Toby Faber. I like the history a lot.

At page 125 or thereabouts a nugget fell out. When Strad's were torn apart and studied and one tapped on the belly or top, it was thicker and tapped lower than the bottom by 1/2 to 1 tone.

So, what is going on? The bass bar and post are vibrating the bottom and it is acting as a diaphragm and sending the voice out the f holes?

I went over to my favorite guitar and tapped the top and bottom - I could hear it. The top tap sounded lower than the bottom. I went to a violin I'm sending back - the top and bottom sounded the same.

If you are looking for a new instrument, I suggest when the dealer gives you four violins to try, tap the tops and bottoms and if you don't hear the above sound differences don't even try them. They will have no voice. Also, run your finger down the back over the flaming. If it feels corrugated or wavy or if the alignment of the strings running down the finger board falls off to one side or the other but the bridge is centered - Stay away from it, it is made out of green wood no matter what the dealer says - very true of Chinese violins. Good workmanship on terrible wood. Some woods are being cut green and instead of aging them, they are kiln dried with fire and heat. These instruments will be very unstable and react to humidity variations to an unreasonable extent.

I am going to take my new four year old wood from a two hundred year old tree and let the air hit all the sides in storage in my shop and hang for quite some time and adjust to the Idaho High Desert and low humidity - but higher than you might expect - center pivot irrigation has added a lot of moisture to our air that use to not be here and the Mountain Home Bombing Range with it's clusters of four bombs will give the wood that well rounded experience from the vibrations we feel all the time, especially if they are dropping bunker busters.

From Karen Allendoerfer
Posted on April 11, 2007 at 1:32 PM

Just to be clear, you mean the "top" as in the front where the strings and the f-holes are, vs. the "bottom" when you turn it over? Or do you mean the "top" as in the part of the instrument closer to the neck, whereas the "bottom" is the part with the chin rest?

Just trying to figure out where to tap . . .

From al ku
Posted on April 11, 2007 at 4:28 PM

i read that book a while back, definitely interesting bits inside.

on the tap tone, you said, when they tore the strads apart, the tap tone was different bewteen the 2 plates.

when we test a violin now, having the top and bottom plates still glued on, do you think the tapping will elicit the similar and hopefully corresponding response?

From Robert Berentz
Posted on April 11, 2007 at 11:29 PM

Karen - The top plate where the f holes are as a whole. I tapped my violin just midway and off to the side of the finger board, or the top of the top and then the same place on the back. This violin was a first born and had a lot of mistakes in it as I understand. The tap tones are the same.

On my excellent guitar (Conn) the tap tones were different. I don't know yet how to determine a half tone and a full tone - it is just a bit higher or lower to me. I'm just learning and have not bought or read the books or listened to the CD.

al - my tests were on instruments that I am playing now and not torn apart. And, yes, you can hear the difference. I would like to go back to Boise and have all of those violins placed on the counter again as they did last Monday. It would be a different story. I think one could definately tap the fronts and backs and come to some interesting selections. Since I am a beginner, I would play them and see if the experiment held true. It is a learning thing.

From Pauline Lerner
Posted on April 12, 2007 at 6:00 AM

Robert, please explain more about how to tap and what to listen for. I just tried tapping on various spots, front and back, of my violin. I heard two kinds of sounds: the "thump" of wood and the ringing of the strings. What am I supposed to listen for? I have some violins that date back to about 1900 and a new one from China. I'm anxious to hear the difference, but I need to know what I'm listening for.

From Robert Berentz
Posted on April 13, 2007 at 10:55 AM

Pauline - tap very lightly and with your ear determine an overall feeling for the sound. Turn the violin over and tap the opposite plate in the same spot, which will be on the left if you tapped the top on the right. If this is confusing, grab the spot you just tapped with your thumb and put your index finger on the opposite side and turn the violin over to see what I am talking about.

Compare the two notes and you may have to do this several times at first to get the procedure into your comfort zone.

What I heard first was a think sound and a thinner sound. The thick sound should be the top and the thin the bottom.

Also, please read my new blogg on moving the sound center which is being used by luthiers while the violin is in the white. There is speculation that the old masters played the instrument in - while the instrument was in the white. They scraped here and there to affect the projection and mellowness of the instrument under construction. Today, we read their comments of playing the instrument in and think playing the instrument somehow magically changes the tone. Not so, instead of tapping, they also used playing and scraping to enhance the characteristics of the new violin. Hope this helps.

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Tap Tone Part II

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