Bow camber question

svenbass · #1 08-29-2007, 12:51 PM

I've recently returned to a heavy schedule of arco practice with my German bow. When in the shop for a fresh rehair, it was suggested that I have the camber adjusted, but I declined because at the time I remembered the bow being fine just the way it was. Now spending 2+ hours a day in arco mode, I'm getting fatigued and have had to be careful not to develop any physical issues. My question to you is: Will a camber adjustment affect the actual physics of energy transfer, or is it a feel/personal preference issue?

I do like the way the bow sounds and feels, it's just that I can't keep it up

...so to speak. (feel free to make fun of that one)

I am taking into consideration that I am in the process of re-developing my arco skills, and it could just be an adjustment period ..... maybe I'm just getting old.

**Basschair** · #2 08-29-2007, 01:38 PM

From what I've learned, the camber would have some effect on the energy transfer, but mostly it effects the even-ness of the tone and how the hair behaves as it's drawn across the strings.

If you are having fatigue issues, my suggestion would be to consider the weight and balance of the bow itself, as well as the tension of the hair and the rigidity of the stick. The weight/balance can effect what muscles are being used and how hard they have to work. I never used to think a few grams or a 1/2" difference in balance point could make a difference until I began working on bows. It can have a profound affect in the long run on your bowing arm.

As far as hair tension and rigidity of the stick goes (this is my personal belief), these can have a marked influence on how much pressure you must use to get the string vibrating (ie: how hard you have to "dig in"). I don't have enough experience yet to fully back this statement up, but perhaps someone would like to add/detract support...?

You have probably considered this as well, but you may want to review your technique just to be certain. At any rate, best of luck!

JimGullen · #3 08-30-2007, 04:55 AM

Greetings!

I agree with everyting Paul wrote. When we make bows, the first thing we do when it's playable (not finished, but haired) is simply draw long slow bows to listen for "swells"...we adjust the camber to take care of those...it can be pretty subtle.

Given what you've typed, checking weight and balance is a good start. My guess, though, is that it's just a matter of getting back into "shape". If you went from basically no arco to 2+ hours a day.....I think that's the issue. Be sure to keep your hand relaxed...as you play and get fatiqued, make sure you're monitoring your bow hand so that you're not employing a "death grip" and exacerbating the issue. I know that you typed that you were monitoring this, but now that you've read it on the internet, it has to be true! :-)

Best of luck and best regards!

Jim

goodgig · #4 09-01-2007, 06:21 AM

Jim, My (older, no-name French) bow has a bit of jumpyness to it. The balance point is at 1/3rd of the bow length. I don't know if the jumpyness is a desirable feature or not, but can a camber adjustment enhance (or tame) this feature?

JimGullen · #5 09-01-2007, 10:45 AM

Quote:

Originally Posted by goodgig

Jim, My (older, no-name French) bow has a bit of jumpyness to it. The balance point is at 1/3rd of the bow length. I don't know if the jumpyness is a desirable feature or not, but can a camber adjustment enhance (or tame) this feature?

Geetings!

I don't have a lot of experience diagnosing camber issues, so take everything I type with a grain of salt! :-)

Is the jumpiness at a specific point or two, or does the stick just not feel "stable"?

If you turn the bow on it's side and sight down the stick, does the camber appear to be smooth for the length of the stick or are there spots that are at differnt radii?

If the curvature is not uniform, a camber adjustment is probably appropriate. If the entire stick just doesn't seem stable, it probably isn't a camber issue but a hair or stick issue.

Your balance point seems like it might be a bit too close to the tip. The number I have for French bow is 8 inches from the butt end of the bow...not the end of the button. Of course, if your stick is 24 inches, it's perfect. There is very little standard on bass bows....big surprise! :-)

I hope this helps a little bit.

Best regards!

Jim

**Basschair** · #6 09-01-2007, 04:06 PM

I'm thinking the same thing as Jim (I think

). Camber seems to have more of an effect on the even sound/tone being produced by a stick (the physics of how the camber stretches the hair evenly are beyond me, but the sound is quite obvious).

As for a bouncy bow, I would think balance point, weight, or elasticity of the stick itself. Loosen your frog to the point where the eyelet is all the way forward in the mortise (just before the screw starts coming out of the nipple), then balance the stick on your finger. Once balanced, pinch that point and measure it from the end of the stick (not including the button), and you'll have a fairly accurate idea of your balance point. 8 to 8 1/2 is about right, though there really is no standard for bass bows. To shift the balance point, you can use a heavier wrap, a heavier metal on the frog/button, a heavier tip material or tip lining, or added weight such as lead tape. I believe 4 grams translates to approximately 1/2" shift in balance point, though I've found it's never exact.

I like the weight to be closer to the frog so that I have a lot of control, yet can get a great bouncing tip for that Rabbath-type stuff.

svenbass · #7 09-01-2007, 10:19 PM

Thanks everybody! I appreciate the feedback.

I certainly am, and will continue to focus my energy on technique, as that really is almost always the root of most issues. The latest discussion on balance and hair tension really shed some light on what might be going on with my bow. I've been keeping the hair somewhat tight for stability reasons even though I get much more bang for my buck when I keep it loose. It seems like I need to have an expert take a look at the bow and check the balance, perhaps adjust the camber, and most important, that I have a few lessons with a teacher that is very familiar with the German bow technique.

The only thing frustrating about all of this is that when I was doing the arco thing about 2 years ago, I had no issues at all with either the bow or physically. I wonder what's changed?

Once again, thanks to everyone for their help. I'll keep you posted!

goodgig · #8 09-02-2007, 05:13 AM

Thanks Svenbass for the post, and to you fellow TBs for your insights! I just joined a local community orchestra (Jacksonville University). Have not yet made the plunge for a $$$ bow and want to first see if I can resolve the issues with the equipment I've got. I measured the balance point as you suggested and it was 8.75" - with a bow rubber on. So it looks like the bow is indeed tip heavy, at least for playing the faster passages, where I find the jumpiness to occur. The camber looks even enough to my untrained eye. There is a bowmaker in Gaineseville - David Forbes - maybe I'll have him take a look and put additional weight on the wrapping.