Violin Forum/Message Board

[Dave Chandler]

Amezcua:

for me, what has worked is 4.3mm wide at the feet, 4mm thick in the heart, and 1.3mm at the top edge. However, I take a scraper and thin the entire upper 1/3-1/4, this is more something you need to develop a feel for.

I usually go through at least two bridges with each violin, taking wood off until I pass that point where the sound starts to roughen, so be prepared to start over, there is no sure answer but what works for that instrument.

Experiment!! take a little wood from the ankles, or more wood from the curves just above and along side the heart. If the A and E sound weak, try thinning the wood just below these strings, etc. If response is slow, thin the upper 1/3 some more. Bridges aren't that expensive, but are probably the single most important adjustment you can make in a violin, except perhaps the sound post.

By the way, a string lifter is an excellent investment, and allows lots of bridge adjusting without detuning and retuning constantly.
_________________
Dave in the Blue Ridge
Southern Violin Association

"Success is the ability to go from one failure to the next with no loss of enthusiasm" Winston Churchill

"I took the road less travelled, and now I don't know where I am." Marco Polo

[John Cadd]

Dave , Those are very good dimensions .They certainly worked for me.I got themfrom a site about all sorts of bridges with a "standard " accepted shape showing measurements.Also the improvement this time was not solely due to the post being moved.There is a complete change in sound quality.What I have been doing is revisiting instruments I made a long time ago before the internet was thought of.
What is the sound that tells you it`s gone too far?
I suppose you could have a group of test bridges ,but would the fit of the feet confuse it or is that not so important at this stage?Each instrument could have slight variations of curvature.
One old article I saw yesterday mentions putting the post grain at right angles to the belly grain and he says "That`s putting too fine a point on the job". How amazing to write that.
An old Strad copy had some very exhaustive tests from the solid wood right through every variation you could dream of.Must dig it out.
How would you experiment on such a thing?
I used a thin marker pen on the varnish which is designed for CDs.There is a pen included that removes the mark when you want.

[John Cadd]

To break a golden rule --How about a set of test bridges which are fitted with some modern glue /filler type mixture and set on the surface using cling film?Very thin layer only.
Tradition would frown on using glue in these situations but would these materials do a useful job permanently? They vary in hardness .

[Dave Chandler]

There are bridges with adjustible feet, cost just a little more, but you could move them from one violin to another -- I don't use them because you end up needing a compound angle, not only must it fit side to side but longitudinally too.

I've accumulated dozens of used bridges, but always end up cutting new. Again, a string lifter will make adjustments quick and easy, and you'll know when you've gone too far, the sound worsens, usually dramatically. Perhaps because you hear sucsessive improvements and all of a sudden its going the other way. You'll know it when you hear it.

A good fit of the feet is your first step, so skipping this step is hard on the finish, and won't let you really hear what the bridge is capable of.

There simply isn't a short cut to a properly fitted bridge. After spending hundreds of hours making a violin, why not spend an hour or so properly cutting the bridge?
_________________
Dave in the Blue Ridge
Southern Violin Association

"Success is the ability to go from one failure to the next with no loss of enthusiasm" Winston Churchill

"I took the road less travelled, and now I don't know where I am." Marco Polo

[John Cadd]

Dave I completely agree . Some of the recent reports of bridge and soundpost research seems to point to the bridge giving the tone and the post giving the balance of volume and smoothness .Both the bridge and post are best considered together.
I shall enjoy this new game .First stop a bridge lifter.
If you have two instruments together ,even if they have different tone qualities,the comparisons of each stage can be very useful.
Thanks for the tips. Just hope the sudden dramatic change doesn`t sound like a loud bang as the bridge hits the belly.(Just joking).

[John Cadd]

What I am doing now is listening to a recording of a Snowy Tree Cricket.( on the internet ) This has a dominant frequency of 2.9 khz and is the recommended tuning for a violin bridge.( see research papers ). I have a steel plane here with the sole upwards and if I compare the sound as I drop various bridges onto the flat sole I hear a rattly tone similar to the cricket recording.
Tilt the bridge before you drop it so that it will rattle.
I have six bridges here and each one has a distinct note.I have laid them out to form a league table.The top one is not far off the mark.
All the finest violins have their bridges tuned to this frequency (plus or minus) This seems to be the message of the paper anyway.
A nice quote ; If you could hear moonlight ,this is what it would sound like.

[John Cadd]

About the 2.9 khz--------anything over this frequency drops away dramatically.That`s in the research graph.

[John Cadd]

So far the difference in tone by tuning to 2.9 khz is amazing.
The post was fitted and has not been moved. I had markers for getting the bridge back in position.All I changed was the bridge tuning.
This one thing is the most important change I have ever made.
2.9khz is not a minor detail.Next time your bridge is off,check the sound against the snowy cricket.

[John Cadd]

Use the cricket site with the six short tone bursts.(not the continous sound).The bridge will ring if you hold it lightly and tap it on the plane..
The top 1 1/2 cms is the part that raises the frequency.
I have just used this method twice and have got a 100 % result both times.