Hi Ed, ><< I am now completely against the concept of tuning the front >duplexes. While it is possible to hear and tune the rear lengths, the >front lengths are just noise. >> > >Greetings, > It is also worth mentioning that different styles of "setting the pin" >will cause signifcant differences in the string tension of the front duplex. >When the tension in the topstring is so variable, how can one expect it to be >tunable? >Regards, >Ed Foote Exactly Ed, I also have been mindful of this effect. But my post had already turned into half a book (these Friday nights after work are very dangerous for wear and tear on the keyboard). Furthermore, when the bars are a smoothed, radiused and hardened, the strings render much better, but the problem will always exist - so tuned front duplexes are out. There is no doubt that the friction effect must result in an out-of-tune front duplex, even if the length is perfect. Herein lies the problem, when the frequency of the duplex is almost in tune with the matching harmonic of the speaking length, there will be considerable sympathetic transfer across the capo from the speaking length to the front duplex. When there is slight out-of-tuneness between the duplex and the speaking length, a 'chorus effect' is bound to result, complete with the attendant string noise. On the other hand the back duplex can be tuned very accurately by lightly rubbing the speaking length to raise the duplex pitch (using a hammer shank in our case), or rubbing the duplex length to lower it. Provided the duplex length is set at the correct length to enable the rear duplex tension to be just slightly higher or equal in tension to the speaking length tension when both are in tune, the piano will be sure to hold tune under the influence of a 'thrasher'. If the block is not set to the correct position, the tension will be set significantly higher or lower when the rear duplex is tuned. Such a situation will result in the string tension variation between duplex and speaking length to gradually become equal via string creep over the bridge, between tunings. In fact, this is the way we know if the block is correctly positioned. If the tuning stability stays without string creep, then we know that the correct block position has been achieved. If the speaking length drops in pitch the duplex length needs to be increased, and vice versa. With a freshly strung piano, it takes about six months of fine adjustment to get the blocks accurately positioned for good tuning stability. Ron O -- Overs Pianos Sydney Australia ________________________ Web site: http://www.overspianos.com.au Email: mailto:ron@overspianos.com.au ________________________
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