7 replies to this topic

[Don Noon]

There had been a recent thread on Violinist.com about age and change, which got me interested in seeing what I could dredge out of my database. Unfortunately, I don't have good data for my first few fiddles, and most of them were taken apart and modified in short order. However, on #4 - #9 the initial measurements were made in the same way I make them now, and I can make comparisons to the response after 2 to 6 months. Here is the averaged response, and the difference over the time period:

There may be some low-frequency gain here, but the high-frequency gain looks like the major effect. Undoubtedly there are adjustments that are included in the results, but my guess is that these are minor effects and are averaged out. No major internal structure changes were done.

For violin #4, it has the distinction of being nearly 2 years old and I haven't taken it apart or modified it in any way, other than the usual adjustments of the bridge, tailpiece, soundpost, etc. It has seen very little playing at all over the period, probably a few hours total. Here are the response curves and the difference.


This is one of the times it would be good to have data taken from a calibrated rig to reduce the chances of getting a systematic error in the measurements, like a change in the hammer (it wore down, and I had to replace some wood) or a variation in how hard I hit the bridge. However, my opinion is that most of the change is in fact a real change in instrument response... primarily stronger high frequency response above 1 kHz, but possibly some gains in the lows, ~450Hz and below.

[carlobartolini]

Don, very interesting the gain that happens in the aprox 2, 3 k range, and on #4 quite a lot.

[Ernie Martel]

For violin #4, it has the distinction of being nearly 2 years old and I haven't taken it apart or modified it in any way, other than the usual adjustments of the bridge, tailpiece, soundpost, etc. It has seen very little playing at all over the period, probably a few hours total. Here are the response curves and the difference.

However, my opinion is that most of the change is in fact a real change in instrument response... primarily stronger high frequency response above 1 kHz, but possibly some gains in the lows, ~450Hz and below.

Don
Since there have been no structural changes and no real playing time...do you think the curing of the varnish has something to do with it?...ie. less dampening?...and did you use the same ground/varnish system on fiddles #4-9?

-Ernie

[James M. Jones]

Don
Since there have been no structural changes and no real playing time...do you think the curing of the varnish has something to do with it?...ie. less dampening?...and did you use the same ground/varnish system on fiddles #4-9?

-Ernie

or ANY thoughts as to why the change? interesting.

[Torbjörn Zethelius]

My guess: the instrument is adjusting to string tension.

[Don Noon]

Since there have been no structural changes and no real playing time...do you think the curing of the varnish has something to do with it?...ie. less dampening?...and did you use the same ground/varnish system on fiddles #4-9?

My guess: the instrument is adjusting to string tension.

There are known changes that occur to wood as it adjusts to a freshly applied static load, so I would guess that's at least some of it. There is also a known change that happens when a white fiddle is freshly varnished, and I would also imagine that it would reverse some (i.e. damping would decrease) over time as the varnish continues to cure. Most of my fiddles had been strung up and played for a week or two prior to varnishing, so some of the wood changes might have been prior to the first measurement. But I really don't know.

I should also mention that 5 of the 6 instruments in the average were made with thermally processed wood, but looking at the change in the first few months of the one made from unprocessed wood, it looks similar to the average... some gains in the low and high frequencies.

That might not be too surprising, as the processing (I believe) does more to speed up the extremely slow changes that occur over many years, rather than the relaxation and varnish changes that might be responsible for these early changes.

[Wm. Johnston]

This is one of the times it would be good to have data taken from a calibrated rig to reduce the chances of getting a systematic error in the measurements, like a change in the hammer (it wore down, and I had to replace some wood) or a variation in how hard I hit the bridge. However, my opinion is that most of the change is in fact a real change in instrument response... primarily stronger high frequency response above 1 kHz, but possibly some gains in the lows, ~450Hz and below.

I have an impact hammer setup that I built and now I always do a calibration run where I tap a plexiglass plate and look at the response. This has been good and bad in a lot of ways. The good thing is that I trust my measurements a lot more and can now compare measurements taken a long time appart. The bad thing is that I spend a lot of time having to rearrange things in my living room. I've found that just small changes in the positions of furniture can make fairly large changes in the measurements. My two main calprits for changes in the room's response are the chair that I'm not sitting in when I do the meaurements and my guitar amps. These things have a habit of moving around the room and need to be returned to just the right position if I'm trying to do careful measurements.

[Michael_Molnar]

At Marilyn Wallin's Setup Workshop a related issue came up. She felt that my violin E string was not performing up to the rest which were pretty good, if not very good. She pointed out that in a couple of months the bridge hill would adjust to the tension from the soundpost which in turn would reduce the tension holding the soundpost. Then, I should just slide the post a tad to the treble (if the post did not "walk" to that position.) This would improve the E string. She and others said that I should replace the soundpost in a couple of months with one that is a bit longer to account for the bridge hill movement. This would bring up the tension for the initial soundpost position.

The point of this story is that Torbjörn is on the money, IMO.

The rest of the story about this violin is that I had Dominant strings, but failed to find my regular E string - a Jargar Forte E. I threw on a Westminster E instead at the Workshop. Once I got home I ordered some more Jargar Forte E's, made the replacement, and played the violin. There is indeed a noticeable improvement. I am very happy.

In another month I will re-examine the soundpost once the bridge hill re-adjusts itself under tension - if I still have this violin.

Staying Tuned.
Mike