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Old 02-26-2007, 12:45 PM
Bob Branstetter Bob Branstetter is offline
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Join Date: 01-22-2007
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Quote:
Originally Posted by Ken McKay View Post
I haven't messed around with TP after length tuning on basses much but do on violins as it can help with carrying power. In a violin I shoot for more power in the 2.5k range. I believe this is standard practice with the better violin set up artists. I don't achieve it consistently and the concept is a bit ellusive. The only way to test for the change in carrying power is to listen far away from the instrument, while it is being played with other instruments. I can get a rough idea of how well this might be achieved by measuring or listening for the right overtones up close to the instrument.

But with a bass it is unclear to me what I would be shooting for. Is there any standard for bass set up regarding afterlength tuning or TP weight?
I think that most of us can agree that moving the tailpiece forward or back will change the feel and the response. It's the afterlength tuning to some arbitrary pitch that is a bone of contention. I received most of my early training in the shop of an award winning violin maker. It was here that I learned about the 1/6 rule for after length, My mentor was very good at setting up instruments and tweaking them for best sound. Although he did deviate from the 1/6th rule on occasion, for the most part, the fine tuning consisted of swapping out tailpieces both in different density woods (ebony, rosewood and boxwood) and in style (Std and Hill) which no doubt was basically adding or subtracting weight. He would also swap out different weight and styles of E string adjusters. He must have done a pretty good job with this method since he won several international awards for tone in violin making competition.

I follow the same basic methods as my mentor did. I don't know of any shops that "tune" the afterlength on violin, viola, or cello to an arbitrary pitch the way some do in the doublebass community. I've often thought it would be interesting to ask those who "tune" the afterlength to accurately measure the playable string length and the afterlength and to calculate the ratio.

There seems to be another rule of thumb that heavier tailpieces work best for arco and lighter ones for pizz. I've found this to be true on most instruments, but just as with bridge height adjusters, there are some basses that do not follow this gereralization. My belief is that the optimum weight for a tailpiece is dependent on the afterlength and the vibrating portion of tailgut. If you examine the motion of a tailpiece, you observe that it moves in several directions at once. It twists on it's axis, it goes up and down and it goes side to side. It also vibrates at a constant frequency. Since the tailpiece does is not struck into motion like a marimba bar, the force that sets the tailpiece in motion has to be transfered to it via the afterlength and to a lesser extent the tailwire. Once the mass of the tailpiece is set into motion, some of this motion is sent back to the bridge which in turn sends it to the body of the instrument. If you change either of these, you change the vibrating frequency of the entire tailpiece assembly. You can also change the tailpiece frequency by adding or subtracting weight from the tailpiece. IMO, it is the mass of the tailpiece and the resulting vibrating frequency that has the greatest impact on the responce of the bass.
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Last edited by Bob Branstetter; 02-26-2007 at 02:50 PM.
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