Bow quality

[Mat Roop]

In a previous thread  https://maestronet.com/forum/index.php?/topic/354777-violin-bow-trial/ 

Andrew Victor said " If you can feel vibrations in the stick while playing, you have a pretty good idea that the string vibrations are not adequately damped in the bow."

So, what are the qualities of a good bow that enhances the damping of string vibrations? 

 

Can someone explain the physics principles of how the bow does the damping? 

Thanks!... Mat

[J-G]

Bow maker Andreas Grütter has a detailed discussion of how bows work in the "book" presented on his website.  Damping is one of the topics he explores in detail.  Hope you'll find it useful, Mat.

https://www.andreasgrutter.com/a-bow-on-the-couch/

 

[Spelman]

That is a good read

[GoPractice]

First,

16 hours ago, Mat Roop said:

In a previous thread  https://maestronet.com/forum/index.php?/topic/354777-violin-bow-trial/ 

Andrew Victor said " If you can feel vibrations in the stick while playing, you have a pretty good idea that the string vibrations are not adequately damped in the bow."

 ( ... )

In context of the post, I believe Mr Victor comments were about good bow behaviour. Chatter is never good. Mild vibrations are necessary for many of us. It's another sensory data point. 

The common thing that players might experience is the abrupt change of the smoothness of the bow stroke when trilling during a soft passage, often of longer bows ( upper half ) in lower positions. If the chatter occurs in the lower half, there might be arm weight and finger pressure issues. In the upper half, with a gentle hold, the bow is reacting to the energy of the quick changing of pitches. The tapping of the above note causes excitation up the string into the bow, on the other end of the string. A gentle shimmery effect is turned in stutters between the fast switching of two notes. Kids react to this by playing with a ( dull ) steak knife pointer finger and squeezing down into the string.

At louder volumes, if the string amplitude is great a bit chaotic, perhaps with older strings, depending on the contact point or ever changing contact points ( ahem ) the badly behaving bow may not stay on the string very well. 

[GoPractice]

Second,

17 hours ago, Mat Roop said:

 ( ... )

So, what are the qualities of a good bow that enhances the damping of string vibrations? 

 ( ... )

Better behaved bows rescue many of us who are a bit chaotic in our playing. Sometimes, fatigue sets in, or inaccuracies, but a silky smooth bow can be great for normal playing.

For those who run closer to the edge of the cliff, the breeze and wind are overwhelmingly intoxicating.

Some super awesome rehairs, all hairs working at once like sled dogs, ones that sound and feel uniformly creamy from tip to frog ( obviously on great stick ) appear ( to me ) to bring out or enhance uniquely powerful and sonic colours. A very underrated player who sounds this way gets monthly rehairs as the sound falls off.

For students, I think a messier rehair is the better way to go.

I think the effect of uniform tensions tends to notch and filter a certain frequency range. A peakier form of overall absorption in the higher frequency spectrum. The messier hair, a flatter, more vague curve.

That is just the hair. When we start to talk bow tightening and tensions, there are sweet spots as to how tight. or loose.

Camber, wood tapers, density changes, all fluctuate to a degree. It is difficult to CNC and bake uniform bows given a choice of woods. It is also difficult to convince players to change bow hair tensions and hand positions unless they arrive at them by intuition or practice.

There is a young lady I teach who figured out at pulling the down bow and "pulling" the up bow by keeping flexible fingers in both directions produces a richer sound. Over the summer she slowly reduced the contact of the fingers to the index and ring finger because it sounded better on long bows. After working towards restoring a more normal touch on all fingers, it is likely she needs a better bow. The problem is that long bow is only one aspect or quality of many pieces. After improving other strokes, like Martele, perhaps we'll go shopping.

Martele, is a stroke where the action is of a quick unspringing of the bow after loading ( gripping the string ) a bit. It can be easier with slightly looser hair as it grips and rotates/ grips most the strings better, but not necessarily for all bows. Once the bow is unsprung, it needs to be able to grip the next note and repeat. If it is still freely vibrating ( chaotically ) there is a slight delay in achiving the grip for the next note, reducing clarity and the immediacy of the note.

[GoPractice]

Third,

On 8/29/2022 at 8:56 PM, Mat Roop said:

 ( ... )

Can someone explain the physics principles of how the bow does the damping? 

Thanks!... Mat

Needed a day to sort some thoughts.

At auction tables, so many of us are unscrewing frogs looking for details. I learned an immense amount watching others. Many waved me away when I casually asked questions. The newer generation has their approach when assessing bows, with photos and other data points. Of course, the old adage was, "time is money." It has always been that data is knowledge. Looking good also helps. 

Before we can go to the dry erase board of physics principles, bowmakers trained with other bowmakers. They must have a set of principles that relate to bowmaking. Sourcing materials must have been important. The internet was much slower then. Currencies were far from established forms like Bitcoin. Barter might have been involved? What would it take top get materials from the coast?

[GoPractice]

After completing a rehair, or restringing an instrument or post adjustment, there were rituals that were developed.

Pre- stressing strings brings strings to pitch faster. Depending on how gentle ( or rough ) one was, the stressing can reduce "string life." Playing instruments to confirm post adjustments help. Selecting hair and planned prepping helps my rehairs. There are those who have no prep, experts that have completed thousands of rehairs who rehair bows way better, than any results from my prep rituals. Let me put in a plug for Triangle here.

As a teen, I recall feeling the voice of instructors vibrating through the bow. The first was rather soft- spoken and a thoughtful person. Actually all were soft spoken. Most of my instructors were very articulate. Not like me. But when he laughed or was very direct - the bow buzzed. He was the teacher who selected the bow. Unfortunately, the bow was broken, decades later, by a student. In my naive process of trying to better student abilities by presenting them with better equipment. At the auction table ( or VSA competitions, ) way way back, I could feel such vibrations. But I could also feel how a bow behaved without the frog, without tension, by tapping the stick. How many of us sit on a broken early Peccatte copy? Do not throw it out... 

At my dealer visits, I rarely take a frog off a bow. They show me, I see, and the questions are answered after the bow is played. With employee turn over, I would assume that I have out lasted hundreds in half as many shops. The better dealers, unless pressed, mostly show the best of what they have.   

So after many auctions and visiting dealers across the world and techs and completing rehairs, I make my own evaluations. Some cities are more visit friendly. Get a rental car in Southern California.

Generalizations are not intended here. I am at a part of my career where bows that are expressive and dynamic are a priority. Some bows behave horribly at low and max volumes but sound great overall - for my abilities. I live with these. Not a very good bow for most players. My knowledge and development grew on adapting. I play many bowed instruments and a need to explore "early music" required that I be purposed to learn.

There is more to write but let me end here: with a very resonant instrument, somewhat peaky to its own favorite resonances, a better behaved bow helped. On more restrained instruments, the more adventuresome bow was fantastic.

More thoughts follow.

 

[GoPractice]

Just microwaved the Entree to lunch. I have not used the appliance for 2+ years, except for as a clock. There are books stacked on top. Had to get back to work. Had wonderful Mexican leftovers but the cheese would have tasted better heated. So, moved the crap infront of the door, popped in food. Press.

I pressed a new button. The machine had a work cycle ( duty cycle? ) that was x seconds on then 5 seconds off. I had never heard that change. I was busy attending to other things. Had never heard this... The weight of the books on the microwave suppressed certain frequencies that I had not before.