Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Upright regulation - double blow when playing softly

Hi,

I notice that when I play p or pp, I get a kind of double blow for keys below the middle range. I suspect this is normal to some extent but on my piano (a restored 1941 S&S V) it seems more pronounced than my gf´s parent´s small 1980 Schimmel. Actually, I never found this was an issue for me before. My Z also had it but not as much.
Maybe it´s because I'm only now able to actually play so softly but anyway - is this something that can be improved with regulation? It might be worth to note that the piano has not been regulated since it sits in my flat.

I'm asking because my tuner will come by on Thursday and I'd like a second opinion.

Thanks!

In vertical pianos, the lowest notes of the long bridge are prone to problems at p and pp.
Solutions and limits will vary from piano model to model.

What kind of hammer return spring does the piano have, and how strong is it?
Were the return springs replaced in restoration?

How big is the hammer? (Those low tenor hammers are "front heavy" and are slow to leave the string.)
Were the hammers replaced in restoration? Are they too big?

Are there "special tricks" to regulate the low tenor in this piano, to improve pp playing?

Ideally, these questions should be answered by someone with experience restoring S&S Vs!

You might gently ask your technician about his/her specific experience with pianos like this and dealing with this problem.

Thanks for the answers.

He's the guy who restored the piano - he has plenty of experience with restoration I believe. The hammers are new. I just realized I didn't notice this when test-playing it extensively. Could this also be caused by my floor being not completely flat (house is from 17th century, so that's quite likely)?

The let off might be set too closely to accommodate softer playing. Might require a compromise.

Curious to find out the resolution. I am restoring a 1915 K and notice the hammer return springs have different specs for the upper and lower sections. Heavier springs at the bottom.

I believe you have an older V with a spring rail. In that case, chances are that there is excess lost motion, possibly with insufficient aftertouch or too much hammer blow. In addition, it may not be checking properly.

There is a different reason for double-striking for spring and loop actions.

Just checking if I got this right - setting the let off very closely allow for softer playing but at the same time makes the piano more prone to double beats?


Sorry, I couldn't follow... what are the consequences of what you wrote?

The consequence is that you may only need minor action adjustments. But I cannot be sure.

When you play very softly there isn’t enough rebound energy to put the hammer into cheek. Or the light touch could be releasing the check. If the let off is too close it could allow double strike. (Especially in a grand with too high repetition spring tension).

If the hammer springs in an upright are too weak then the hammer might not be pushed away from the strings enough to avoid a bobble. Old style rail springs can be bent to give a stronger return if needed.

So, there are several things that can lead to a double strike. Almost always it can be regulated away.

My opinion as a beginner pianist and amateur regulator of my own piano (but also an engineer) is there are three interwoven factors in that the whole double-strike issue. They are:

-partly due to the inherent design of uprights where gravity is not your friend in getting hammers to return when they are teetering on the brink of double-striking
-partly due to regulation issues (let-off adjusted close to the strings can worsen the problem), in Yamahas from the 80s the hammer spring securing cords will be broken unless they have already been replaced
-partly due to player technique.

The technique part shouldn't be overlooked. As a beginner I have limited flexibility and control of my LH fingers and often do not play the key fully and end up with a keystroke that leaves the hammer "hovering" and just waiting for a further small oscillation to make it re-strike. Doesn't happen with the RH. (I am right-handed).

I can replicate this behaviour on my teacher's very similar upright, but it doesn't happen when she plays just as quietly, because she has good finger control and technique.
Some pianos are probably more sensitive to technique than others.

Some uprights are more sensitive to casework front/back levelling. It would not be too difficult for you to test this out before your technician arrives. First check the level either with a spirit level or by accurately measuring the top and bottom of one of the rear verticals to the wall. You can then slip spacers (e.g. hard drink coasters) under the front or rear wheels and check the bobbling.
Ian

Pianos cannot be played infinitely quietly.
As you move from mf - mp - p -pp - ppp - pppp you will reach a point where the hammer either bobbles or fails to touch the string, or touches the string and stays there.
This will depend on the inherent limits of the particular action and also on tiny adjustments of parts and springs.

In a fine piano a good technician may offer several subtle possibilities, depending on what the pianist is willing to risk in return for what benefit.
In a fine vertical piano, the limits of ppp almost always arrive first in the lowest hammers on the long bridge, typically around D below middle C.
You have discovered a limit in your piano. Many pianists will never play quietly and attentively enough to notice what you found!

Now you can work with the technician to find out what is possible on this piano that you will most enjoy.
Good for you! Customers like you give us reason to do our best and keep learning!

I can clearly hear bobbling hammers on Glenn Gould records......so even the best make tradeoff decisions!
Nick

Keybender, please let us know how it goes tomorrow.

This is very helpful, thank you. I tried different ways of playing softly - I can feel the let-off point (please correct if I use the wrong vocabulary).
What I've discovered is that when I play extremely softly - not even going past that point then I can play without the bobbling. There seems to be a "no go area" between this and a bit harder playing where it doesn't occur. Sort of like "ppp is okay, pp is bobbly but p is okay again".


And Ed Sutton: You're almost spot on, I'm impressed. I think it's actually the E below middle C, so there you can still improve

On a side note: this is actually one point where a digital piano is better regarding fine control. Somewhat unexpected but I find it has to be taken into account when practising on my digital.

Yes! I've heard bobbling on Gould CDs too!

Live blog here: she said something about springs being too hard and seems confident it can be improved.

edit: yep, definitely better. Will post again soon once I've had a chance to play for a bit. Unfortunately I also have to work today

Guys, I'm really excited, she did a great job.

It's not only much better, I'd almost say it's all but gone. The softest sound may be a tiny but louder now but it's waaaay more predictable and I now even have trouble provoking the bobbling.

It'll be a while for me build enough skill to get the lowest ppp out of the instrument reliably.

It worked and I'm really happy. Just for clarification the shop owner send one of his technicians but he'll show up personally for some tweaks to the intonation.

Glad things are working out for you!

Ask her what she did..

I meant to, but I had to join a conference call and thus say goodbye before she was done with everything

Her boss will do the intonation in october so I'll get another chance to ask, he'll probably know.