Hi Will Frustratin ain't it? Stwy Damper systems are notorious for there thump especially by a player who is using IMO poor pedal technique. The pedal si realeased quickly by the foot with a swift upward motion. Drive me nuts!...Show up on recordings etc... Part of this phenomena occurs because of the weight to the dampers/underlevers/lead in conjunction with how far the tray pivots are located back on the tray. All this weight sits out on the end of a what amount to an essentially very long lever, the edge of the tray, where all the weight from the parts rest....far from the pivot... clear? When I replace trays I relocate the tray pin to be in line with the under lever center. In this system the tray cannot fall with as much inertia as before and the whump is usually, in my experience, eliminated, even if the poor pedaling technique continues. With the pivots in this new position it is necessary to install two coil springs on the tray to achieve adequate return pressure to the trays rest position. No big deal. I have also experimented with moving the pivots only 1/2 the distance to the underlever pin position which is also helpful in dealing with the whump & aslo the screwy way the damper upstop positions need adjusting to accommodate two different line of travel rotation. The underlevers rotate around one orbit based on the realtive pin location & the the tray around another. See the problem? A 0 any way... Another issue is that IMO sufficient damping is not possible with out springs & some spring tension and ESPECIALLY in the bass. The New Model O for example has no damper return springs installed & the one I worked on had the same poor damping. The Steinway mother ship was not interested in my feedback or opinion. So, After 150 something years suddenly springs are not used....come on. It does sound like the plate is resonating. Unless some one has effectively come up with a bar damping protocol you are stuck. This is easily demonstrated to your client as not you fault. One last thing. Look at the length of dampers on the old models. Compare it the new. The amount of felt used in the past & forever was quite modest & were cut to very precise & specific lengths. I believe it was to avoid nodal points of contact in the bass & to also minimize the whooshing. Less felt less whooshing. This require cutting the new felts to length. Sorry I wrote this quickly...Forgive any errors in whatever. Clarity? Hope it helps. Dale Erwin To my esteemed colleagues on the list: A couple of days ago I sent a post to the Forum regarding some damping issues I am having with a Steinway L on which I replaced the underlever system and the damper heads, and with which some interesting problems have developed. I had hoped for some feedback and diagnosis from damper experts wiser than I, but so=2 0far no bites. So I am reposting the query, in the hopes that some of you will find it interesting enough to comment. I surely would be most grateful for anything offered, as I will be working on the piano in the next day. My earlier post below: About 8 months ago I replaced the back action on a Steinway L that is roughly thirty years old, along with all of the damper felt. This was a Teflon action, and the Teflon was in the process of slowly freezing up. I had replaced the shanks and whips and hammers, and the customer elected to have the back action done at the same time so as to remove the last looming issues with the aging Teflon. I used the Tokiwa kit for the back action and the Tokiwa grand damper felt, with which I have had good success in the past. About 2 months ago my customer called me and complained about how noisy the dampers had become. I scheduled an appointment and, sure enough, her complaints were justified. Her complaints were: 1) When she lifts the damper pedal, there is a fairly prominent woosh as the felt exits the strings – you know, that HAAAA sound. 2) When she releases the pedal, there is a fairly loud WHUMP as the dampers settle on the strings. 3) With the action removed, if I lift the tray with my hand and drop it, the WHUMP still occurs. (This means that the issue is not in the trapwork because I have removed it from the train here, and the problem remains). 4) If I stroke across the bass strings with the dampers on the bass strings, there is a fairly prominent hangover of the string excitation before it dies away – not unlike doing the same thing on across the bass strings of a spinet 5) On a staccato blow, you can see the damper felt fluttering on top of the bass string before it quiets it, accompanied by a ZUP kind of sound 6) If I lift that damper and drop it onto the string (without engaging the action at all), the same ZUP occurs. 7) If I tap on the bass plate struts, they ring for 1 to 2 seconds. I can feel them vibrate when the pedal thumps. When I replaced the underlever system, I duplicated the leading and spring configuration of the original system. The original underlevers had 3 leads in the bass up to note 30, 2 up to note 46, 1 up to 59, and 0 from there. Ditto for the leading on the new set. The originals did not have springs, so I did not install any of the springs that came with the Tokiwa kit. Frankly, I don’t know enough about how the decisions are made for leading and springs, so I duplicated what was there for configuration. Of course, the new underlevers are longer than the old ones, which had to be accommodated in the locating o f the tray, and the height and depth of the tray pivot pins. I would like to further note that all dampers are lifting and moving freely. Action centers in the damper system are sufficiently free. I built and used the locating jigs for the tray that were in the Journal article a while ago. I spent quite a bit of time setting things up and double checking. I am confident that the tray is located properly fore and aft and side to side. I have done a lot of grand damper work over the past thirty years and feel I am pretty good at it. I reused the original wire with the new felts, and it was my experience that the wire did not ask for an unusual amount of wire bending in any direction, which supports my notion that the tray was located with good accuracy. The damper sizes and lengths were duplicated. Given the list of clues I have presented, it is natural to suspect that the damper felt is too hard, even though it is brand new. But I have replaced the Tokiwa felt on several test notes with Larouex felt. At best, there is a very small improvement, so I don’t think that the felt is the whole enchilada. Probably I will be replacing all the damper felt when I go back this week. But I am not confident that will solve the whole problem, and think I should perhaps also install damper springs. Whatever I do, I would like to make good decis ions up front so as to limit my own bloodletting here. So, I would be most grateful for the expert diagnosis of my compadres, given my list of symptoms. Thank you again for whatever you have to offer. Will Truitt -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech_ptg.org/attachments/20081229/1fd49bf8/attachment-0001.html>
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