Greetings, I wrote:
I set the underlever springs by measuring several along the length and marking them with a spot of chalk after setting them to the appropriate tension. Turning the whole assembly upside down, I give it a slight up and down shake. It is easy to then set the entire rack to the index underlevers by simply pushing the levers down a little until they also move the same amount as my guides.
Regards,
David asks:
What tension do you like that balances effective shut off and minimal touchweight differences with and without the pedal.
I like the least amount of tension possible. Usually that is the minimum recommended by the string kit,(can't off hand remember what). It also means on a the upside-down damper tray, with flanges and springs attached, the underlevers will all bounce together, with the more treble ones showing a little more motion, tapering to virtually no spring at the last sprung lever. . The heavier underlevers will thus have heavier springs. I do taper the spring force so that there is no discernable "step" between the last spring and the first unsprung underlever. I think the work is actually being done by the weight, and while the springs contribute to the down force,(of course), their pressure doesn't allow the string movement to throw the dampers back upwards and off the string under heavy oscillation.
The slow motion pictures of dampers reseating have amazed me in that the upward string excursion can send the dampers, (and underlevers), upwards strongly enough so that the damper leaves the string after contact. I think the springs do a lot of work simply preventing the underlever's momentum from causing the assembly to leave the string.
Also, as Kent mentions, it is very easy to weaken a spring too far, so one has to learn how little depression of the upside down lever it takes to bring its spring into agreement with the guides. This is not a scientific approach,but rather, one that I have empirically arrived at. It takes into account the resistance provided by the friction of the spring as it slides.
Regards,
Ed Foote RPT
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