Technical problems and their resolution

C. Bechstein Konzert8 upright and mechanical problem

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titowsky

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Opening post by titowsky

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24
City
Radolfzell

Good evening,

i had an excellent opportunity to trade in my upright piano for a Bechstein Konzert 8 that is practically new, which many consider the best upright in circulation. I tried several here in Germany until I found one that particularly struck me.

The sound is truly exceptional, clear yet melodious at the same time, powerful and enveloping in the bass.

After a few days of intense practice, however, I have some concerns regarding the action that I was not able to verify as minutely during my tests in the shop.

in case of rapid repetitions of the same note, especially if very delicate (including very fast trills/mordents), sounds are lost on some keys: looking at the internal mechanism, it seems that at a certain point the hammer remains as if blocked by something in its starting position and does not "rebound" until the key is released almost completely.

The problem is more evident on some keys and much less, or almost not at all, on others.

The action, absolutely new and (so they say) extensively checked before delivery, is in my opinion rather light and with a key travel that is not very wide (I amateurishly measured between 9-9.3mm).

Bechstein advised me to wait for a good settling-in period and to play the instrument to allow it to acquire "elasticity": sincerely, I am not very convinced that things can improve just like that.

Thank you for any opinion/advice!

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Reply 2 by Fra

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266

I would try to advance the pusher brake a little bit; I believe that when it trips, it goes too high on the repetition lever and doesn't have enough time to return for the repetition, this happens with all the verticals when the brake is too far back, it must have a minimum amount of play but not too much.....

Obviously this is following all checks (hammer regulation in check, play between pusher and repetition lever at rest, escapement etc)

Try to advance the brake and see if I'm right.

Ciao

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Reply 3 by Fra

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266

http://www.pianoconcerto.it/forum/uploads/images/pianoconcerto_1387322856__image.jpg

It would be position 10 of this drawing.

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Reply 4 by titowsky

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24
City
Radolfzell

Thank you very much for the advice... excuse me, but I don't feel very comfortable touching the action personally: I prefer to wait for a good technician and perhaps suggest this solution, verifying it together with him. But I am truly happy to know that the matter is resolvable/improvable!

I will keep you updated, thanks again!

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Reply 7 by Fra

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266

the piano is new, what problems do you want it to have? Don't worry....have the hammer parameters checked as well, they will probably need to be adjusted later too

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Reply 8 by torrese

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242
City
casorate sempione varese

Dearest Fra, I take this opportunity to propose to you, if you wish, to make short tutorials on the setup of our friend the piano; we would be very grateful to you. I believe I speak on behalf of all those who, like me, love to untangle themselves in the adjustments of the piano mechanics. Furthermore, I take this opportunity to wish you happy holidays.

saverio

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Reply 9 by titowsky

Posts
24
City
Radolfzell

Good evening,

I am reporting an update, following today's visit to the Bechstein showroom and feedback from their most experienced technician, complete with an explanation in front of the open action of a similar Konzert 8.

Regarding the interventions I could perform myself, it was suggested that I add two thin felts behind where the hammer rests (behind the felt strip along the capstan rail), in order to slightly advance this position (excuse the improper terminology, I hope it conveys the same idea). Then, in about a month, he will come to my place in person and check the other possibilities.

I must say that the situation has already significantly improved, both in repeated notes and fast, pianissimo trills... but above all in my sense of security (of producing the desired sounds) at pianissimos with the finger resting on the key or with the key already semi-depressed.

But it must improve even more: Liszt's last Transcendental Etude in very fast tremolos still occasionally causes the hammers to "stick" until I completely lift my finger... or very fast and "brilliant" repeated notes (Chopin's brilliant polonaise style) that I cannot achieve with the naturalness I am used to.

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Reply 10 by pianoexpert

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3,876
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rocca di papa

From what you are describing, I believe it depends on the proportion between the hammer-string distance and the key dip. Naturally, as an emergency measure, the technician advised you to shorten the first distance. Okay, even if you will now feel a slight "void" under your finger before your finger energy is actually transmitted to the action. The dip should not be less than 10mm. The hammer-string distance should be about 45mm and no more than 47mm.

Also check the spoon that lifts the damper. Sometimes it carves a "dent" in the felt that receives it, and this blocks the efficiency of the rail/support structure.

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Reply 11 by titowsky

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24
City
Radolfzell

Thank you for the clarifications. The technician warned me about that "void" under the finger if the thickness were excessive (he kindly prepared several felts for me to add and try)... but I must say it is truly imperceptible.

So, by also correcting the key dip, would the situation improve? From a quick measurement, it seems to be just under 10mm (the technician told me that even around 9.5 was okay)... but my feeling is that it is minimally lower than the standard.

Thank you again and have a good Sunday!

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Reply 12 by pianoexpert

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rocca di papa

Absolutely not 9.5. Everything must be brought back to the correct values. And the mechanics absolutely need to be adjusted again. To quickly increase the key dip without intervening on every single key, which carries the risk of upsetting the proportion between white key dip and black key dip. The Technician must act on the central bar of the keyboard. By unscrewing the screws that fix the keyboard frame to the board, a thin piece of cardboard is placed in correspondence with only the central bar screws. By screwing them back in, the dip of the white keys is remeasured. When we have 10mm, the black keys will also be correctly adjusted. Obviously, bring the hammers to a minimum of 45 mm from the string and adjust everything. The recipe is ready. Just serve it at the table

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Reply 13 by titowsky

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24
City
Radolfzell

It seems easy... all I can say is: let's hope for the best! I have scheduled the intervention for February: I really think I can trust one of their most experienced technicians (he is even a builder as well as a tuner, someone who has been repairing and tuning Bechstein for a lifetime, even for the most important performers)... he is the only person here to whom I am able to report problems in detail, expecting to be heard and supported.

I will keep you updated. Have a good Sunday

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Reply 14 by titowsky

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24
City
Radolfzell

...I also have the feeling that I have slightly changed the timbre for now, perhaps just slightly muffled... maybe due to the reduced stroke of the hammers caused by the thicknesses added to their back. Maybe it's just my impression...

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Reply 15 by titowsky

Posts
24
City
Radolfzell

No: it's not an impression... it actually feels as if I were playing with half or 1/3 of the effect of the left pedal pressed (and with the left pedal completely down, my defect almost disappears). Now I understand what you meant to tell me, Paolo... So for now, felt strips removed: I won't compromise on the sound.

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Reply 16 by pianoexpert

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rocca di papa

Well. It is feedback for me that my suggestions actually correspond to the remedies and sensations experienced. As for the Technician, he can only be an expert, who will surely want to intervene in an effective and essential way.

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Reply 17 by titowsky

Posts
24
City
Radolfzell

Good evening,

finally I can provide an update on the situation.

Two weeks ago, I had the opportunity in the Bechstein showroom to discuss the defects of my Konzert 8 (especially the problem of repetitions with hammer blocking) with their most experienced technician (and showroom director)... as well as noting that similar issues occurred on two other Konzert 8 models.

The technician confirmed that the regulation was not optimal, and we "worked together" for a couple of hours specifically to understand how best to intervene on very similar pianos.

Last week, he therefore came to my house and spent 4 hours with me on my piano, collaborating with me very patiently, note by note, to improve the situation.

To make a long story short... now the repetitions are much better: it is no longer so easy to block the hammers... in short, performances are not compromised (I have various "test pieces" such as Liszt's last Transcendental Etude with very light tremolos, or Schumann/Liszt's Widmung, or Scarbo, which were previously impossible)... but I am still left with a sensation of slowness/inertia in the key return upon releasing the finger.

When I mentioned that on the 124cm Bechstein I previously owned, the action felt more "natural," "direct from finger to string," and fast... I was told that this is typical of slightly smaller uprights: the Konzert 8 has a different, more complex action, which paradoxically, to guarantee incredible sound performance for an upright, sacrifices some of that "immediacy" that satisfied me so much. I must say that after trying many Bechsteins (and various Konzert 8s), my feeling has been quite similar.

The technician also explained to me that pushing further on the speed of the repetitions could lead to the phenomenon of double-striking the key in case of light pressure... something I immediately noticed on some notes and which absolutely must be resolved.

In short... a great improvement, but not the definitive resolution: I am speaking in terms of my own pianistic sensations, but confirmed by many tests and reflections... the Konzert 8, despite having a fantastic sound that does not make one miss a mid-level grand piano, currently has an action that is more difficult to control and less satisfying in certain technical aspects.

One last note: one note (the second natural below middle C) sounds "different" from the others. It sustains less, it is less full... this is especially noticeable when using the right pedal to sustain a phrase. It is the last note of a specific section of strings before moving to the bass strings... and I was told that this aspect makes it a bit "different." The technician also intervened here; now the inequality is less perceptible, but I... well, I might be being pedantic, but I still hear it.

Now I apologize for the length and leave space for comments/questions from anyone interested or who wants to give me further advice. (This way I can take advantage of the technician, who will return in a couple of weeks to fix the final details).

Thank you!

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Reply 18 by Andry

Posts
86
City
Roma

These findings are very interesting, I do not have the expertise to give opinions and therefore I only have a curiosity that I would like to satisfy: why did you decide to change your Bechstein 124, was something no longer working well?

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Reply 19 by titowsky

Posts
24
City
Radolfzell

Just for extreme perfectionism and passion... the Bechstein 124 was mechanically splendid and had a beautiful sound, but:

- it had a problem of prolonged resonance in the soundboard (in practice, an "anomalous" echo would be created even after releasing the keys... nothing to do with dampers or mechanical problems; investigating this aspect further, it seems to be a common problem for many 124s, even confirmed in confidence "by those who shouldn't"...) Annoying.

- Feeling of delicacy in tuning: it tended to go out of tune very easily... but I wasn't yet so attentive to controlling the room humidity, so it might also be my fault.

- The sound was nonetheless quite bright, wonderful compared to other uprights... a bit metallic and less refined when compared to the Konzert 8. The difference is noticeable.

Finally, if one has this immeasurable passion as in my case, combined with the opportunity to try many pianos in various Bechstein showrooms scattered across Germany... the tendency to always want more is inevitable

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Reply 20 by pianoexpert

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3,876
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rocca di papa

Dear friend, I really don't understand what "forcing the speed of the repetitions" means… perhaps the Technician is referring to the hammer return spring? (check the key dip… when it is shallow… then the hammer indeed "trembles" near the string, especially in pianissimo!!!)

I absolutely believe that your dissatisfactions stem from a problem with the friction of the center pins. This is an instrument that must function like a clock. I guarantee it. It's a pity about our distance!!! Replacing the center pins is very delicate work. One must have straight, non-tapered reamers, which I advise against. The longevity of the work over time depends on it. By doing this, the action "is reborn"!!!!!! Then one can proceed to a fine regulation!!! Only after that!!!

Tuning stability: one must check the stability of the tuning pins. Naturally, I firmly believe that this piano is not well "voiced", meaning the sound has not been made uniform in its overall timbre. Furthermore, if the sound results as excessively bright across the entire keyboard, this can further highlight slight out-of-tunings. (The voicing work is also difficult and tricky....)

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