I have a 2005 Yamaha Grand Mark IV Disklavier DGC2. It is a fantastic instrument. I do have one big problem with it, however. When the dampers come down on the strings there is a loud "THUD". I have adjusted the lift of the dampers so they do not have as far to fall back, but the thud is still pronounced. I cannot lower the the dampers any more or the trichord felts will be touching the strings. I could and probably will install new damper felt, but I have been working in this business long enough to know that may not solve the problem. Do any or you have any suggestions?

In my store I also have a 2004 Yamaha Grand Mark III Disklavier DGC1 which does not have this problem at all.

John Adair RPT

Biggest suggestion: Make sure the noise is coming from the dampers themselves, and not somewhere else in the pedal mechanism. Compare it with holding all of the dampers with the sostenuto, and then releasing it. That should be louder in any case, but listen to the quality of sound as it happens. You want to rule out the pedal cushion, or something else between the pedal and the damper tray. The player mechanism adds more possibilities.

Does the thud happen when you use the pedal manually, when the player system uses the pedal, or both?

Don't forget checking out any possible noises coming from the trap work itself or, from the damper lever that could be landing on that little L shaped bracket under the key bed...

Have you calibrated the pedals in the "service center" program in the PRC-100? It is something that should be done whenever the Disklavier is moved or the trapwork is adjusted. It may help reduce the noise a great deal.

It is pretty simple to do. If you're in the main interface screen tap on the red square in the lower left hand corner. Then tap on "service center". Once you are connected tap on "pedal calibration".

Thanks for your thoughts!
1. Matt, Yes, I have calibrated the pedals in the "service center" program of the PRC-100.
2. Jerry, I have checked the trap work and it is clean of any noise.
3. Rich, Yes, the thud is there during regular playing yet not quite as noticeable because of the human element. However, when the same midi file song is played on my other Mark III Disklavier there is no thud of the dampers.
4. Semipro Tech, I will work on your suggestion regarding the sostenuto test.

Thanks again. I'll report back.

John

If the damper felt has been subject to a little humidity and dust the felt may have hardened (like a very minor doping effect) a stiff short haired brush (or toothbrush) can be used to delicately clean and soften the fibres again on the underside. At first the damping will sound like it's off but after a few hours it will pack down again with hopefully less of a thud

Just to clarify.. don't use a wet toothbrush! Or toothpaste for that matter

John,

The loud "THUD" you are talking about, would you describe it as what one sometimes calls "oinking" or is it something different.

Just curiouis because I posted a damper problem here recently and would be interested if there is something to be learned from your thread.

http://www.pianoworld.com/ubb/ubb/ultimatebb.php?/topic/3/4507.html#000000

http://www.pianoworld.com/ubb/ubb/ultimatebb.php?/topic/3/4456.html#000000

schwammerl.

It is the damper felt. In order to lessen that whump sound is to artfully "mis-adjust" the damper lift slightly so that they don't all hit the strings at once in coming back down. You may also very slightly tilt the damper heads in the bass forward so that the fronts hit slightly ahead of the backs as they come down, or, in other words, that the backs lift very slightly ahead of the fronts as they are lifted.