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#612120 - 02/11/09 02:10 PM SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
I. Bruton Offline
500 Post Club Member

Registered: 10/20/04
Posts: 861
Loc: Raleigh
I have a new (about one year old) Kawai K3 in my high school chorus classroom that keeps double-striking...on nearly every note! It is very annoying, yet I have no money in my budget that will allow me to hire a technician to fix this problem. Besides, there are no registered piano technicians in this area, and the dealer is not willing to bring one in. This dealer thinks that Kawai can do no wrong, and neither can their in-house technician (who's 80 years old and doesn't know a double striking hammer from a double bird strike on that US Airways flight!What am I do to?
_________________________
I. Bruton
B.A. Music Composition
M.M. Music Education
High School Choral Director
Church Music Director
Pianos owned: Yamaha C3
Pianos at work: Yamaha P22, Kawai K3, Steinway B

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#612121 - 02/11/09 02:24 PM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Jerry Groot RPT Offline
6000 Post Club Member

Registered: 11/07/07
Posts: 6828
Loc: Grand Rapids Michigan
1. Could be loose hammer butt heels or loose hammer butt heel shanks.

2. More than likely, it doesn't have enough key depth and needs a good regulation.

Hiring a good technician is really, the only solution to this problem. The two listed items above should not take but a couple of hours to correct at best unless there are a lot of other issues going on.

Are you in South Carolina? Contact Ron Alexander. He's on this piano forum often and can easily solve these problems for you. I do believe he travels there...
_________________________
Jerry Groot RPT
Piano Technicians Guild
Grand Rapids, Michigan
www.grootpiano.com

We love to play BF2.

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#612122 - 02/11/09 03:15 PM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Silverwood Pianos Offline
4000 Post Club Member

Registered: 03/10/08
Posts: 4182
Loc: Vancouver B. C. Canada
Ah Jerry,
Raleigh is in North Carolina I believe....unless there is another one I don't know about..... :p

Dan Silverwood
www.silverwoodpianos.com
_________________________
Dan Silverwood
www.silverwoodpianos.com
http://silverwoodpianos.blogspot.com/
http://www.facebook.com/SilverwoodPianosDotCom
"If you think it's expensive to hire a professional to do the job, wait until you hire an amateur."

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#612123 - 02/11/09 03:22 PM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Jerry Groot RPT Offline
6000 Post Club Member

Registered: 11/07/07
Posts: 6828
Loc: Grand Rapids Michigan
Oops! I knew Ron was in NC! Sorry bout the typo!!
Thanks for the correction Dan!
_________________________
Jerry Groot RPT
Piano Technicians Guild
Grand Rapids, Michigan
www.grootpiano.com

We love to play BF2.

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#612124 - 02/11/09 03:25 PM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Silverwood Pianos Offline
4000 Post Club Member

Registered: 03/10/08
Posts: 4182
Loc: Vancouver B. C. Canada
ah, it's only a couple thousand miles one way or another.....

Dan Silverwood
www.silverwoodpianos.com
_________________________
Dan Silverwood
www.silverwoodpianos.com
http://silverwoodpianos.blogspot.com/
http://www.facebook.com/SilverwoodPianosDotCom
"If you think it's expensive to hire a professional to do the job, wait until you hire an amateur."

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#612125 - 02/11/09 07:40 PM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Ron Alexander Offline
1000 Post Club Member

Registered: 06/17/03
Posts: 1292
Loc: North Carolina
I about 3 1/2 to 4 hours from Raleigh, near Charlotte. Bruton, there are plenty of Registered Techs in your area. Check PTG.org.

If this piano is only a year old it is still under warranty. Whether you bought it from a Kawai dealership or not, INSIST they take care of the problem.

If you need my assistence, PM me. I will help in any way I can.
_________________________
-----------------
Ron Alexander
Piano Tuner-Technician

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#612126 - 02/12/09 03:23 AM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Gregor Offline
Full Member

Registered: 10/31/08
Posts: 431
Loc: Münster, Germany
I assume we are talking about bobbling hammers? I recently started a discussion about that in the PTG mailing list and many good answers came from techs which post and read here as well. But one point was not discussed: is that really a warranty issue? A piano that was used for one year in a high school could need some regulation, but I am not shure if that would be a warranty issue.

Gregor
_________________________
piano tech - tuner - dealer
Münster, Germany
www.weldert.de

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#612127 - 02/12/09 08:48 AM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
I. Bruton Offline
500 Post Club Member

Registered: 10/20/04
Posts: 861
Loc: Raleigh
Thanks for the replies...we have very reputable technicians in Raleigh, including the Ruggeros. Unfortunately, my school is an hour east of Raleigh, in Goldsboro. We have very few reputable technicians in this part of the state.

I will not work with the Goldsboro, NC dealer anymore as they are extremely difficult to work with. They didn't even prep the piano, it was delived to me still in the crate!

Also, since this is a school district in an area with a lowsy economy, I have no money to hire unless I pay out of my own pocket.

So...here's what I've done for a temporary fix.

I adjusted the spring tension on each note and it seems to have stopped for now. The piano is playing good again, but I hope I haven't done anything that could cause damage down the road. Of course, I wouldn't do this under normal circumstances, but I was desparate.
_________________________
I. Bruton
B.A. Music Composition
M.M. Music Education
High School Choral Director
Church Music Director
Pianos owned: Yamaha C3
Pianos at work: Yamaha P22, Kawai K3, Steinway B

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#612128 - 02/12/09 09:15 AM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Gregor Offline
Full Member

Registered: 10/31/08
Posts: 431
Loc: Münster, Germany
 Quote:
Originally posted by I. Bruton:

I adjusted the spring tension on each note [/b]
Wow, not bad. Are you sure you are not a piano technician? ;\)

Which spring and how did you do that? Did ýou weaken or boost it?

Gregor
_________________________
piano tech - tuner - dealer
Münster, Germany
www.weldert.de

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#612129 - 02/12/09 09:20 AM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Silverwood Pianos Offline
4000 Post Club Member

Registered: 03/10/08
Posts: 4182
Loc: Vancouver B. C. Canada
“They didn't even prep the piano; it was delivered to me still in the crate!”
--------------------------------------------------------------------------------------
Drop- shipping is the sign of a dealer who is trying to squeeze every dollar out of a sale. This is not a dealer I would be confident in working with either.

Putting more tension on the spring work will change the touch slightly depending upon how much you have changed it. I think in the end Jerry’s assessment was correct…you might have a balance rail felt compression which has resulted in too shallow key dip. (key not going down far enough).

School districts always make this claim about a lousy economy. In reality, districts are run through the tax program (mill rate) and taxes remain the same or go up, so this claim of having no money is a bogus one. There will always be enough money to run the system. It is just a way of starving the music programs…..heard it all before many times.

By reading your signature line, you have some pretty good equipment there to work with. Hopefully you can get the district to see that maintenance is linked to longevity, which in turn saves funding in the long run. I always had an uphill battle with that one though too.

Dan Silverwood
www.silverwoodpianos.com
_________________________
Dan Silverwood
www.silverwoodpianos.com
http://silverwoodpianos.blogspot.com/
http://www.facebook.com/SilverwoodPianosDotCom
"If you think it's expensive to hire a professional to do the job, wait until you hire an amateur."

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#612130 - 02/12/09 09:40 AM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
I. Bruton Offline
500 Post Club Member

Registered: 10/20/04
Posts: 861
Loc: Raleigh
 Quote:
Originally posted by Gregor:
 Quote:
Originally posted by I. Bruton:

I adjusted the spring tension on each note [/b]
Wow, not bad. Are you sure you are not a piano technician? ;\)

Which spring and how did you do that? Did ýou weaken or boost it?

Gregor [/b]
I'm far from being a piano tech! But I've done some reading on the subject by searching the archives here at PW. Someone mentioned the spring tension, so I tightend it somewhat for each note that was double and even triple striking. I think it's called the jack spring.
_________________________
I. Bruton
B.A. Music Composition
M.M. Music Education
High School Choral Director
Church Music Director
Pianos owned: Yamaha C3
Pianos at work: Yamaha P22, Kawai K3, Steinway B

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#612131 - 02/12/09 09:53 AM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Bill Bremmer RPT Offline
3000 Post Club Member

Registered: 08/21/02
Posts: 3036
Loc: Madison, WI USA
I had run into a similar problem with 4 or 5 Kawai verticals at a school that were there on some special kind of deal. The dealer sent me there to tune them. It was winter when everything indoors is very dry, so we usually do find pianos low in pitch but these were ridiculous.

They were so flat and out of tune that they needed extra work to tune them. To make things worse, there was so much lost motion that the pianos were unplayable. Excessive lost motion causes a loss of after touch which will result in the "bobbling" hammer or double striking effect.

This presented two dilemmas: if I raised the pitch all the way to A-440, the same pianos would likely go very sharp as soon as the season changes. If I adjusted all of the lost motion so the pianos would play correctly, it could have been that seasonal changes would have also caused the regulation to change just like the tuning so that the pianos would again become unplayable with the hammers standing far above the rest rail.

My solution to the problem was to report it and do nothing at all. I don't know what became of those pianos or if anyone else did anything about it. No one was willing to pay for what it would take to get them playing properly and even if they had been, I could have been blamed for "messing them up" just a few months later.

Generally, I recommend Kawai verticals for schools specifically because their action screws don't get loose and they hold their regulation better than any other brand of instrument.

However, I had a similar problem with a Yamaha vertical many years ago. It was unplayable in winter due to excessive lost motion. I corrected the problem and charged for the work only to be called back in summer when it had an equal and opposite problem. I turned the capstan screws back down for free and the piano played just fine again. Then, the following winter, there was that problem with lost motion all over again. In both cases, the problem was worst in the middle of the keyboard as it was with the pianos in the school that I mentioned above.

This indicated to me that the keybed was rising and falling or swelling and shrinking. Some verticals have a metal brace in the middle which I think may help to hold it from bowing up or down with seasonal changes. I don't know whatever became of the Yamaha piano because after three attempts to correct the problem, that customer never called me again.

I hope Don Mannino will comment on this because he is a very responsible and sensible representative for Kawai and surely must have heard other reports of this kind of problem.

Turning capstan screws to adjust lost motion is not a difficult task. However, to just get someone to do that and then find an equal and opposite problem again a few months later would put that person in a difficult position.

Simply saying that the room needs humidity won't usually work in that kind of situation either because the moisture level cannot usually be maintained the way it could in a home. Humidifiers can also cause other kinds of problems and resulting liability issues.

An in-piano, humidity control system might help but it would cost at least $350 and there would be no telling how long it might take to make any difference. It is also difficult to ensure that such a system is watered and remains connected to power in a school. Even the power cord is a public safety issue, especially in schools. What usually happens is the system runs dry and gets unplugged and everyone thinks the whole deal was a waste of money.

My guess is that this is an Indonesian made Kawai. I have had no particular problem with those pianos, in fact, I have been impressed with how well they have arrived from the factory. I've only found minor and typical adjustments being needed as the piano gets used.

I think the "some settling of contents may have occurred" issue applies in this case. Was the piano like that when you first got it or did it get worse and worse as winter came on? That would be an important clue. Capstan adjustment of nearly any piano can be expected after a year.

I would suggest contacting Don Mannino at Kawai about the problem first to see what he has to say about it. Then, I would suggest finding a way to pay to have Richard Ruggero RPT come out to tune and regulate the piano. Sometimes, urgent funds can be found from a PTO or a choral booster fund. Capstan adjustment is usually not considered to be a warranty issue but a normally required maintenance procedure. However, in this case, since the problem is so severe, there may be some kind of compromise which can be reached between the manufacturer and those who normally pay for piano service to have someone who knows what he is doing get the piano playing properly again.

Good luck.
_________________________
Bill Bremmer RPT
Madison WI USA
www.billbremmer.com

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#612132 - 02/12/09 10:08 AM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
I. Bruton Offline
500 Post Club Member

Registered: 10/20/04
Posts: 861
Loc: Raleigh
Thanks, Bill, for that information. For what it's worth, this particular K3 was made in Japan. Also, the double striking issue has been there all along, but it recently got much worse (in the last month). Normally there were just a few notes doing this, but immediately after it was tuned by a local non-RPT guy, the problem was made worse. I don't think he made any action adjustments at all, so there's probably no connection there.
_________________________
I. Bruton
B.A. Music Composition
M.M. Music Education
High School Choral Director
Church Music Director
Pianos owned: Yamaha C3
Pianos at work: Yamaha P22, Kawai K3, Steinway B

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#612133 - 02/12/09 11:02 AM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Ron Alexander Offline
1000 Post Club Member

Registered: 06/17/03
Posts: 1292
Loc: North Carolina
No, the tuning would not contribute to the problem. Without seeing the piano, it is probably an action regulation issue, made more severe by the dryer humidity. The spring adjustment may only be a temporary fix. I hate to hear these stories of "out of the crate" sales. These types of sales usually lead to dissatisfied customers, but word gets around about sellers who will not stand behind their product.

I heartily agree with Dan. The school systems have in the past managed to find funds for the projects they deemed a priority. And I have seen numerous situations with frustrated choral teachers. Bruton, I would suggest at least bringing this situation to the attention of the school finance guru, you are probably going to need to have someone look at the piano and do some regualting by this fall.
_________________________
-----------------
Ron Alexander
Piano Tuner-Technician

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#612134 - 02/12/09 12:57 PM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Jerry Groot RPT Offline
6000 Post Club Member

Registered: 11/07/07
Posts: 6828
Loc: Grand Rapids Michigan
In a church choir room just the other day, I read a poster that the choral director had hung up it said this. "THE ART'S ARE FUNDED BY THE UNARTFUL." I had to laugh as I read it thinking, how true this is in so many cases.
_________________________
Jerry Groot RPT
Piano Technicians Guild
Grand Rapids, Michigan
www.grootpiano.com

We love to play BF2.

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#612135 - 02/12/09 02:09 PM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
I. Bruton Offline
500 Post Club Member

Registered: 10/20/04
Posts: 861
Loc: Raleigh
Thank you all for your thoughts on this issue. I was completely expecting to get bashed for making these adjustments myself, but that didn't happen. If these small adjustments will last until June, I can probably get some more thorough work done in August (new fiscal year!).
_________________________
I. Bruton
B.A. Music Composition
M.M. Music Education
High School Choral Director
Church Music Director
Pianos owned: Yamaha C3
Pianos at work: Yamaha P22, Kawai K3, Steinway B

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#612136 - 02/12/09 03:56 PM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Scooters Offline
Full Member

Registered: 02/03/09
Posts: 227
Loc: N.E. Montana
hi,
What I have seen in the past is the music dept. does a fund raiser. Band candy, Chorus cookies, and maybe a bake sale. Label it for the repair and maintenance of the school piano. Put up a collection in the gym for a football and basketball music fee to keep the band playing and giving support at the games.

The most important part of the event will be for the tuning and continued tuning of the piano.

This will make the board take notice and when done with all due respect, will have a profound effect on your department and you for your ambition and undeterred movement to the ultimate goal for the good of the Music Department. ;\)

Good luck Sir,
Scooter
_________________________

Scott
Associate Member Piano Technicians Guild
RsgPianoService
We love to play BF2

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#612137 - 02/12/09 08:31 PM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
KawaiDon Offline
1000 Post Club Member

Registered: 02/05/02
Posts: 1206
Loc: Orange County, CA
 Quote:
Originally posted by I. Bruton:
= This dealer thinks that Kawai can do no wrong, and neither can their in-house technician [/b]
If your school has a tuner that you use regularly, have the tuner call Kawai tech support with the serial number and his/her observations about the piano. It should be fixed, not ignored.

Once we sort it out, we'll talk to the dealer about how they should handle these kinds of issues.
_________________________
Don Mannino, MPA
Kawai America

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#612138 - 02/12/09 11:53 PM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
daniokeeper Offline
1000 Post Club Member

Registered: 02/01/09
Posts: 1056
Loc: PA
You may want to check the blow distance, too. I encountered something like this many, many years ago on a new piano. The key height, key dip, lost lotion, etc... all were correct. But, the blow distance was too much. After this was corrected and then the lost motion adjusted, all was well.
_________________________
Joe Gumbosky
Piano Tuning & Repair
www.tinyurl.com/tunerjoe
(semi-retired)

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#612139 - 02/13/09 05:25 AM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Gregor Offline
Full Member

Registered: 10/31/08
Posts: 431
Loc: Münster, Germany
I am confused: tightening the jack springs would make it worse, wouldn´t it?

My attempt were to weaken the jack springs. Unfortunately there is no way to weaken jack springs that I know of.

Gregor
_________________________
piano tech - tuner - dealer
Münster, Germany
www.weldert.de

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#612140 - 02/13/09 07:49 AM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
I. Bruton Offline
500 Post Club Member

Registered: 10/20/04
Posts: 861
Loc: Raleigh
 Quote:
Originally posted by KawaiDon:
 Quote:
Originally posted by I. Bruton:
= This dealer thinks that Kawai can do no wrong, and neither can their in-house technician [/b]
If your school has a tuner that you use regularly, have the tuner call Kawai tech support with the serial number and his/her observations about the piano. It should be fixed, not ignored.

Once we sort it out, we'll talk to the dealer about how they should handle these kinds of issues. [/b]
I will defintely do that! Thanks Don!
_________________________
I. Bruton
B.A. Music Composition
M.M. Music Education
High School Choral Director
Church Music Director
Pianos owned: Yamaha C3
Pianos at work: Yamaha P22, Kawai K3, Steinway B

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#612141 - 02/13/09 09:44 AM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Dave Stahl Offline
1000 Post Club Member

Registered: 05/06/07
Posts: 1645
I've seen this on a few k3s, too. In my experience, when there have been so many bobbling keys, it was because there was not enough key dip, or because there was too much lost key motion. In some instances, these issues can be exacerbated by overly strong damper springs.

As Dan, Jerry, and others have stated, the balance rail punchings may have gotten compressed, or the balance rail itself may have changed dimensionally as a result of humidity fluctuation.

If there are only a few notes doing this, a quick-fix I've used is to remove a thin paper punching or two from the offending notes to allow enough aftertouch for the action to complete its cycle. This is more easily reversible than bending springs.

If it is en masse bobbling notes, the balance rail may not be high enough. Shimming it with card stock (cut from someone else's business card....)underneath where the screws hold it to the keybed can solve the problem. There would be some re-regulation required. I believe this one would qualify as a warranty repair. It also falls into the "don't try this at home" category.

Normal regulation procedures(lost motion, let off, checking, etc.) wouldn't be covered under warranty by most manufacturers.
_________________________
Promote Harmony in the Universe...Tune your piano!

Dave Stahl, RPT
Piano Technician's Guild
San Jose, CA
http://www.youtube.com/watch?v=JAniw3m7L2I
http://dstahlpiano.net

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#612142 - 02/13/09 10:48 AM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Jerry Groot RPT Offline
6000 Post Club Member

Registered: 11/07/07
Posts: 6828
Loc: Grand Rapids Michigan
Honestly, I wouldn't fool around with it yourself because, if you mess with something that wasn't the cause, it will take whoever comes in to fix it longer to reverse and/or cure the problem plus, please, make sure that you explain to them while they are there, showing them just what you did so the tuner can check it and resolve that issue too if it needs changing back.

Hey, I would like to toss in a plug for Kawai and Don M., if I may.

Recently, I had several nice conversations with Don Mannino over a Kawai with loose tuning pins that my college owns.

As I've said before, Kawai wants happy customers. Within a couple of weeks, I received new tuning pins for the piano with no questions asked. Well, maybe a few! :-))) Inside joke here.. Anyway, the point is, FIX IT JER so, I am... Happier customers makes for more piano sales and recommendations.

My college is probably going to purchase some pianos from the local dealership here in the next year or too after their renovations. More than likely, we'll wind up with the higher end Kawai's.

So, any tech reading this, please, do NOT hesitate to contact Kawai or Don directly. They are wonderful to work with. Especially after they get to know you a bit!
_________________________
Jerry Groot RPT
Piano Technicians Guild
Grand Rapids, Michigan
www.grootpiano.com

We love to play BF2.

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#612143 - 02/13/09 11:55 AM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Dave Stahl Offline
1000 Post Club Member

Registered: 05/06/07
Posts: 1645
I'll second Jerry's suggestion. Very accessible folks. You actually talk to people from the time the phone is answered rather than a voice prompter.
_________________________
Promote Harmony in the Universe...Tune your piano!

Dave Stahl, RPT
Piano Technician's Guild
San Jose, CA
http://www.youtube.com/watch?v=JAniw3m7L2I
http://dstahlpiano.net

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#612144 - 02/13/09 01:49 PM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Bill Bremmer RPT Offline
3000 Post Club Member

Registered: 08/21/02
Posts: 3036
Loc: Madison, WI USA
I agree with the not trying to fix it yourself statements. I am surprised that any spring adjustment did any good at all. Whatever was done with the springs may actually need reversing when the true problem is identified.

Double striking hammers can be caused by one problem or a combination of several and would usually not be the fault of springs. Only in a grand can a repetition lever spring that is overly tensioned contribute to double striking.

It wasn't clear to me which springs you adjusted. If a vertical hammer return spring is broken or out of place, it can cause some double striking but even then, usually not if the other points of regulation are correct. I can't really see how either increasing or decreasing the tension of either the hammer return springs or the jack springs would have helped at all.

The common factor in double striking hammers is insufficient after touch. After touch itself is affected by the amount of key dip, the amount of let off and the blow distance. In a vertical, if there is lost motion when the blow distance itself is correct (where the rest rail sits), the net effect is insufficient blow distance.

A back check that does not contact the hammer butt can also allow the hammer to double strike but most often, the reason the back check does not properly contact the hammer butt is because of insufficient after touch.

You need a technician who understands how all of these work together. From what you have said, the store tuner is just that, a store tuner. In my career, I have known may such people who were highly regarded but who actually had very limited skills. I've heard time and again a blatant disregard for vertical service. "You don't regulate uprights". Yes, I have heard it more often than you would ever believe.

I think the truth in such cases is that the person who says that does not understand these kind of relationships and is not really capable of understanding the complexity of the problem or how to remedy it.

Again, I would suggest you see if you can get Richard Ruggero RPT (or someone he personally recommends)to analyse and correct the problem in consultation with Kawai tech support. You can try the store tuner if you like but I'll bet he won't really cooperate. Don't be surprised if he says "You (or I) don't regulate uprights".

If he does, you'll know right where you stand with him. Chances are that for a knowledgeable technician, the solution is quite simple and the problem can be remedied within an hour's work. However, there can be complex issues such as I wrote about before where the keybed is somehow unstable. It takes someone who has experience with all of these possibilities to identify them, sort them out and correct them.

It is just as important not to try to correct something that does not need correction as it is to correct those points which do need correction. I'm glad you put your problem on this list. We all are genuinely concerned about it and hope you find a solution for it.
_________________________
Bill Bremmer RPT
Madison WI USA
www.billbremmer.com

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#612145 - 02/13/09 11:36 PM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Dave Stahl Offline
1000 Post Club Member

Registered: 05/06/07
Posts: 1645
 Quote:
Originally posted by Bill Bremmer RPT:

Double striking hammers can be caused by one problem or a combination of several and would usually not be the fault of springs. Only in a grand can a repetition lever spring that is overly tensioned contribute to double striking.[/b]
In 95% of the cases, you're right. But I've seen numerous cases where, even in perfectly regulated instruments with adequate aftertouch, overly strong damper springs contribute to bobbling.
_________________________
Promote Harmony in the Universe...Tune your piano!

Dave Stahl, RPT
Piano Technician's Guild
San Jose, CA
http://www.youtube.com/watch?v=JAniw3m7L2I
http://dstahlpiano.net

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#612146 - 02/14/09 02:42 PM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Bill Bremmer RPT Offline
3000 Post Club Member

Registered: 08/21/02
Posts: 3036
Loc: Madison, WI USA
I welcome any other possibilities which others can think of. It wouldn't be the problem in this case but back check and/or back stop material which is severely worn will do it too.

Overly strong damper springs cause double striking? Hmmm, interesting. I can't imagine how. I suppose the bobbling does not happen when the damper pedal is depressed and that is one way of isolating the problem? Please give more details.
_________________________
Bill Bremmer RPT
Madison WI USA
www.billbremmer.com

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#612147 - 02/14/09 04:08 PM Re: SOMEONE HELP! DOUBLE-DOUBLE-STRIKES!
Dave Stahl Offline
1000 Post Club Member

Registered: 05/06/07
Posts: 1645
What happens is as the damper spring is pushing against the damper, the spoon pushes agains the wippen which gives the jack too much spring. I've seen it most frequently in Chinese built uprights using the name of Hallet Davis, and occasionally in other pianos. Usually it is merely a contributing factor in bobbling hammers, but as I said, I've seen it as the sole cause.
_________________________
Promote Harmony in the Universe...Tune your piano!

Dave Stahl, RPT
Piano Technician's Guild
San Jose, CA
http://www.youtube.com/watch?v=JAniw3m7L2I
http://dstahlpiano.net

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