>Ron Overs wrote: > >> At 9:33 PM +0100 16/1/03, Richard Brekne wrote: >> >> >. . . I dont really know what to think about the ratio in this as it would >> >change through the key stroke. >> >> As does a normal grand piano action, ie. one with one capstan, but to >> a lesser extent. >> Ron O. >> -- > >Yes, but wouldnt this be much more noticeable ? Yes >Another thing while I have your >ear Ron... In taking up and down weight measurements, it's almost always >apparent that the lower half of the hammer travel needs more weight >for DW (and >less for UW) then the upper half. This hasn't been our experience. As the jack/roller contact is further away from the line of centres at rest. As the key dip progresses the contact will move closer to the line of centres thereby reducing the difference between up/down weight. However, some actions do have problems with the angle of the balance pin relative to its balance pin hole. This is a common cause of increased down weight at the lower end of the key dip. A higher repetition lever tension will also give the player a feeling that the down weight is heavier at the bottom of the key stroke. >But with the increased ratio spread resulting >from a concave capstan (or some such idea) wouldnt this tendency be kind of >reversed... or evened out at least ? As you say, it would tend to result in a lower ratio at the start of dip. A larger diameter capstan will tend to have a similar effect also. >The hammer at the rest position would then see a key leverage that was reduced >by the diameter of the capstan compared to the the hammer at drop... so it >would take less weight to get the darn thing moving upwards, and >more to finish >pushing it though the stroke. Indeed, our action achieves this also to some degree, since the hammer/key ratio remains more uniform throughout the key stroke (in standard actions the actual ratio is higher at rest, decreasing as the key is depressed). While a great majority of pianists approve of our action, I have a feeling that the few who don't may be put off by the lower than usual ratio at the commencement of the dip, which must also be accompanied by a slightly higher ratio at the end of the stroke if the overall ratio is to remain at some nominal value (in our case we have been setting this nominal value between 5.6 to 5.8:1 - lower in the later installations). >Course you dont need so much leverage to handle things after the >jack releases. True. The jack release rate is an interesting consideration with regard to let off efficiency. The speed of the jack tip must be considered relative to the key movement. A slower jack escapement (in cases where 15 or 15.5 mm type hammer shank is used in combination with a lower key ratio, but with a higher hammer/key ratio) can make an action more prone to 'double hitting' during slow playing. Ron O. -- OVERS PIANOS Grand piano manufacturers ________________________ Web: http://www.overspianos.com.au Email: mailto:ron@overspianos.com.au ________________________
This PTG archive page provided courtesy of Moy Piano Service, LLC