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Metal pin under violin bridge foot


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I was browsing ebay for violins, and I came upon this.



What is that metal pin under the bridge foot for? It says the violin is experimental, but what is the use of that? Anyone have some insight on this?



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I think the answer lies in this snippet from the description...and a lever system that are going through the table under a foot of the bridge.



(sorry about the boldface...It came along when I copied and pasted)


I would guess that the bridge sits on one end of the lever, and the other end is supported by the soundpost.  It's probably one of those inventions that works "after a fashion", but is a lot of trouble and unlikely to revolutionize the craft.


It's a shame the vender wants to start the bidding so high.  I'd sort of like to mess with it.



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There is a trick for using smaller instruments as a viola and having a viola sound by attaching the sound post directly to the bridge through a hole in the top. This looks very much like it, but it could ofcourse be something totally different.


I was actually wondering about that today. If it was possible to make a violin sound more like a viola with some trick while making it etc.



It's the "hole in the heart" technique. It was discussed sometimes here. I think it is something dating from early 1920, maybe in nordic countries?


I found this on the "Hole of the heart" technique: "there is something that’s been dubbed a “hole-in-the-heart” operation. You’d have to get your local violinmaker/luthier to do this for you. They probably won’t be willing to do it to higher quality instruments. It’s kind of irreversable. The idea is to bypass the belly of the instrument alltogether, by drilling a hole under the treble side of the bridge, and attaching the sound post directly to the treble foot of the bridge, thus allowing the sound waves to travel from string to bridge to soundpost to the back of the instrument, instead of from string —>Bridge—>Belly—>Back." - Saw this in a topic where someone asked how to convert a violin to a viola.


Does anyone perhaps know how successful this is? How big of a difference it will make to a violin sound? Will the difference be worth the trouble? (This is, ofcourse, if you want a violin to sound more like a viola)

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I made my 1970's Romanian viola into a 'Hole in the Heart'.  At the same time

I thinned the plates a lot.  There was a good improvement, but not spectacular.


The idea, at least my idea, is that the top plate is no longer forced to have

a node at the sound post, and thus there is the possibility of vibration modes

at lower frequencies, not otherwise available.  I cannot claim any demonstration

of this.  A better craftsman might do better.


The set-up with the right foot of the bridge attached to a long post is fragile!

A broken 'A' string can cause real problems.  Getting the whole thing balanced

so that the stick passes through the hole without touching can be a pain.

And of course, there is no sound post to adjust.  Or at least the rules

for setting it up are unknown.


I do not know what the reference to a lever in the eBay ad is about.

'Hole in the Heart' is just a simple extension of the treble foot of the bridge.

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The "hole in the heart" thing makes sense, and has plenty of historical precedent, but I don't think it fully explains what is going on with the instrument in question.


There is a metal pin (or something) visible in the picture.  This would not be necessary if the sound post just went through the plate and served as a perch for the bridge foot. What is it?


The person who has access to the instrument writes of a "lever system".   It's hard to imagine using the word "lever" in the context of a "hole in the heart" construction.  What is he seeing?





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I wrote this to the vender last night......


"I am having trouble understanding what is going on with the sound post, and the "lever" you mentioned in your description.
Would it be possible to see a picture that sheds more light on this?"


...and I got this response this morning.

"Sorry, but it has inside the violin, impossible for a pics, only visible to the endoscope. There are drawings of the process on the web , but !!!!! "


So....That does not seem like a very useful response from a person who is trying to sell something unusual. I am through trying to get more information from him.



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I'm guessing from the description and photo that there is a soundpost in about the normal spot, but doesn't touch the top, only the middle of a lever.  The pin is at one end of the lever, and the other end of the lever might rest on the top somewhere.  Just a guess.


The hole-in-the-heart is something I tried out on a VSO, and it does strengthen the lower frequencies significantly, as well as lowering their frequency.  However, since the trebel foot doesn't contact the top, the high frequency response suffers mightily.

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  • 2 months later...

Hi.  I now have this instrument.


The violin has a piece of wood running from the top of the soundpost (the soundpost buts into this piece of wood) to the bassbar, attached to the top plate at the soundpost and I think attached to the bassbar.


The metal pin runs from and perpendicular to this piece of wood through the top plate.


There is a large wooden plank attached to the bottom and top block, running perpendicular to the to top plate but not attached to it.  Rather like a very large bass bar down the middle of the instrument. It is deeper than half the distance between the top and bottom plates.  The smaller piece of wood described above runs through the top of and is attached to this piece.


The bridge supplied with it has a hole in the foot to allow for the pin, the pin passes right through the treble foot of the bridge.


I'm not sure if this arrangement of the bridge is correct or not.


Looks to me as if the idea is to transfer the vibrations of the top plate from the soundpost area and bass bar via the small piece of wood to the large plank running down the middle of the violin.


Haven't set it up yet, so don't yet know what it sounds like.

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I am glad to hear that this instrument has ended up in the hands of someone who will appreciate it.  I have a soft spot for experimental-stuff and wish I had the budget to collect them.


I am having a bit of trouble understanding your description of its unorthodox underpinnings.  Could  you make a sketch for us?



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Thank you for the reference to the patent application, most interesting.  I suspect that this instrument is an earlier version as it lacks the hole in the belly under the middle of the bridge and both bridge feet contact the belly.  The metal pin you see in the photo is embedded in the treble side of the "counter-bridge" and as far as I can tell just serves to locate the bridge directly above the "counter-bridge".  Apart from these two differences, the lever system inside is as described in the patent application.  I will comment again after I have set it up for playing.

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Thanks.  Have had another look at it.  The "counter-bridge" is not attached to the top plate under the treble foot of the bridge.

The sound post fits into the bottom of the "counter-bridge" next to the metal pin.

From the preceding discussion on the "hole in the heart" operation, I assume that the bridge that came with the instrument is wrong and that the treble foot of the bridge should sit on top of the metal pin and not touch the top plate at all.

I would appreciate your advice on this.

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Modified about 3 years ago a 7/8 rather lack lustre violin I made early in my career to hole in heart viola..can be done with shorter children's instruments as well for the kids who like the bass better than treble...a difficult process to keep the hole in top plate just larger than the sound post so that it doesn't rub against side..what it does mainly is free up vibrations of the top plate between the f holes as the plate is no longer restricted in movement by being pinched from downward force of treble foot and upward force of top of sd..not bad sound in bass range close to viola sound...treble a bit less rich and projecting. One can add a heavier tailpiece to enhance this conversion..Although the internal volume is smaller than traditional viola range,Violin Physicist Professor Beament in his book says the mathematical calculation of optimal size in violas would result in too large for player comfort...If not careful the post tends to move in direction of string tension or laterally and seize up against inner edge of hole...defeating its purpose

..I can't quite figure out the strange metal pin on this fiddle... doesn't seem to link with treble foot..there is a convex semicircle in the treble foot? treble foot.

Hole in heart described in STRAD about 10 years ago especially for smaller student fiddles for kids who just aren't likeing the violin tonal range and prefer viola like sounds. One uses a glued dowel about 2 mm diameter and 5mm long set into ankle of treble foot(the foot being first removed at mid ankle..also set into the top of sd. post and glued. Dale P "Chanot"

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