Do pianists notice small changes in let off and aftertouch?

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Withindale
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Do pianists notice small changes in let off and aftertouch?

Post by Withindale » 08 Oct 2011, 10:55

I bought my 1925 Schiedmayer & Soehne upright privately to learn to play during my retirement, when that time comes. Meanwhile I am learning to regulate it. The hammers are in good shape, as are the keys and the action. The piano had not been heavily used but its settings were completely out of whack and dynamic range was lacking.

With no shims behind the hammer rail, blow distance is 44 mm; key travel is 10.3 mm for 3 mm hammer to string distance at let off. When the keys are pressed slowly down to the front cushion dip needs to be about 10.7 mm for the jack to just escape and the catcher to just meet the backcheck.

My question is whether experienced pianists will actually notice any differences in sound, or after touch, from one key to another when I set let off (a) by hammer to string distance and (b) by after touch.

To clarify (b): when a key is pressed down slowly the key travels 0.4 mm from the point of maximum hammer travel to the point where the jack is just escaping from the but leather. With a 0.4 mm spacer on the front rail one can adjust the let off button to set maximum hammer travel (it is easy to find the precise point where it is about to fall back). This ensures even after touch across all keys at the expense of slight variations in hammer to string distance due to differences between hammers, maybe up to 1 mm. Vice versa for (a), hammer to string distance at the expense of increased after touch.

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Re: Do pianists notice small changes in let off and aftertou

Post by Barrie Heaton » 08 Oct 2011, 15:41

Your answerer is in your last paragraph, it how it feels not the measurement, measurements are there as a guide not an absolute. When you have a worn piano they are less important, getting the action to feel even that is more important.

To deep a touch can make the backs of your arms ache A 44mm blow should work with a 9.5 depth of touch (dip) look at your jack slap rail (to close), the state of the check felt and balance hammer leather. If the leathers have been changed is the nap running 6 to 12 o'clock

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Re: Do pianists notice small changes in let off and aftertou

Post by Withindale » 08 Oct 2011, 17:35

Thank you, Barrie. I feel it's better go for even aftertouch and not worry about a delay of one or two milliseconds in the odd slightly worn hammer hitting the strings won't be noticeable. But I'd be interested to know what experienced pianists think, hence my question.

Key dip is the main issue with this piano. The hammer rail appears to be in its original position and the jacks do not come anywhere near the slap rail as they escape. It takes 11 mm of key travel to move the hammer 44 mm from to the strings when the let off button is raised so the jack never reaches it. The action ratio appears to be on the low side compared with most pianos and the old Ibach I looked at the other day which works happily with 9 mm key dip and 50 mm hammer travel.

Some European experts aim for 2 mm let off distance (3 mm bass) while the Americans go for 3 mm. I'd estimate 8 mm let off will be necessary for 9.5 mm key dip but, if this too much, it might be worth trying 10 mm key dip with 6 mm let off or 10.2 with 5 mm. However it seems to me the piano may naturally have 11 mm key dip, so it may be better to stick with the current 10.7 mm. Alternatively I could move the hammer rail forward by 5 mm but that was how it was. When I took all the extra spacers and punchings out, leaving the German ones, it immediately sprang to life.

I'd really appreciate your opinions because no one still knows what Herr Schiedmayer and his sons had in mind when they designed the piano a century ago.

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Re: Do pianists notice small changes in let off and aftertou

Post by Barrie Heaton » 08 Oct 2011, 20:12

But how many times have the hammer been refaced Most European piano have 45mm 47mm and a lot of old English pianos had 50mm Blow Depth of touch (Dip) is 9.5 to 10.5 some modem Yamaha upright pianos come out of the factory with 11mm Depth of touch and they feel fine

You can have a 4mm setoff (letoff) and 12mm checking and the action feels OK with a 50mm blow. Now a 45mm blow 2mm set off, 12mm checking and 10mm Depth of touch (dip) on most modern pianos will improve the repartition, as you are altering the angel at which the jack attacks the notch (called the rake ) However, you must have firm front touch punching or you are in danger of blocking with a 2mm setoff

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Re: Do pianists notice small changes in let off and aftertou

Post by Withindale » 08 Oct 2011, 21:42

Withindale wrote: Now a 45mm blow 2mm set off, 12mm checking and 10mm Depth of touch (dip) on most modern pianos will improve the repartition, as you are altering the angel at which the jack attacks the notch (called the rake ) However, you must have firm front touch punching or you are in danger of blocking with a 2mm setoff
Barrie,

You highlight two points I had not considered before, the jack's angle of attack and the firmness of the front punching. When I looked there was indeed a slight risk of blocking on one or two of my sample keys but also a little more scope to reduce setoff than I had estimated.

It's amazing how such small adjustments add up to improve the feel of the instrument, and that must be the answer to my question about pianists.

The voice of experience is greatly appreciated. Thank you.

Ian

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Re: Do pianists notice small changes in let off and aftertou

Post by Barrie Heaton » 09 Oct 2011, 11:46

its demising returns any improvement in most uprights outhere will be noticed However, the high end tweaking to the end of the pianos action working envelope will only be appreciated by grade 8 and above and they tend to move on to better pianos which out of the box are close to what they want

Then there is the cost factor in time spent. would the client pay. With some of the cheaper pianos out of the far east are so far from the truth and badly made you would find it very difficult to get less then 4mm set off with out changing components

We use to use 3 to 4mm front touch baize and make it up with card now a lot use 5 to 6mm this saves time and masks badly made keys that clunk. Andre Oorebeek a piano tuner in Holland has invented a conical washer made from felt which is hard the conical shape reduces action noise but they are not cheep

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Re: Do pianists notice small changes in let off and aftertou

Post by Withindale » 09 Oct 2011, 14:45

Barrie

Your comments have triggered these notes.

Yes you are right about about improvements in uprights. After I had done some of the basic stuff Reblitz describes, our tuner, who is also a musician, said the piano was fine, which it was up to a point, and recommended leaving it alone - because it's easy to do more harm than good. But as soon as I started on Oranges and Lemons I knew the piano should have more to give. Generalisation: many pianos underperform but who is prepared to pay to do something about it.

Since the tuner's visit five things have each produced dramatic improvements: reshaping the hammers (by massaging the felt to remove the compacted ridges at the ends of the grooves - an unprofessional method, I know); straightening the action which was slightly twisted ( a five minute job loosening and retightening a dozen screws in the way recommended for car wheels; diagnosis took much, much longer!); setting the strings; tightening the main plate bolts; and regulating the action (a work in progress as in this thread). Not knowing what to expect and what to look for has been the problem all along.

You mention André Oorebeck; one of his posts about grand pianos http://mail.ptg.org/pipermail/pianotech ... 00861.html stressed the importance of setting aftertouch and he kindly sent me a method for uprights. Your points about the angle of jack attack and front punching completed the explanation and enabled me to see how setoff could go down to 2 mm without too much extra key dip.

Fortunately I have no experience of the Chinese pianos you mention. I have heard some are getting a lot better, and most will be benefit hugely from a little attention from an experienced technician who knows how they should sound.

My penny's worth on the huge potential benefits of piano technicians' work, especially on uprights!

Ian

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Re: Do pianists notice small changes in let off and aftertou

Post by Barrie Heaton » 09 Oct 2011, 16:26

After touch is not the same on an upright as a grand. An upright has not got double escapement like a grand.

in Europe we tend to like a soft feel after touch, in the USA they like a firm after touch, so much so that some techs put the rollers on the wrong way round so that the nap is running the wrong way and gives them a positive clunk from set off to drop. Myself I am not keen on doing that, as in soft playing its too noticeable and you are introducing more friction to that last 1mm of play. However, you can set the rep spring a tad weaker than you would to ensure that the carding gap is there to allow the jack to return to play, with the roller on backwards the Jack is working with the nap not against it. if that makes sense.

Carding is the gap between the top of the jack and the rep lever they use to use a piece of card to get the correct gap.

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Re: Do pianists notice small changes in let off and aftertou

Post by Withindale » 09 Oct 2011, 17:58

Of course grands and uprights are different but there are similarities too. André Oorebeek started by saying he had complete break through, "when I learned that a hammer travel distance gauge is not necessary anymore."

Conventional wisdom for uprights seems to be set key dip, blow distance and set off. People then say there is a "resultant after touch". They also say this after touch may have to be 0.75 mm or more. This means you can feel the points where the jack engages, where it escapes, and where it hits the cushion. As I understand it André advocates that the key reach the cushion as the key escapes. The cushion, perhaps one of his conical Crescendo washers, then gives an after touch sensation.

By setting the after touch (i.e. key dip beyond the point of let off) precisely to 0.4 mm, or whatever is appropriate, one gets minimum key dip and even after touch. This is also a more precise way to set the point at which the hammer actually leaves the jack on its way to the string. Unlike set off, as determined by hammer to string distance, it does not depend on the depth of felt at the crown of the hammers.

Oh dear, I am meant to be asking for advice! But I am, I have 84 keys still to go or all 88 maybe.

PS Thanks to increased jack angle, change in the point of escape around the curve of the butt, I found the amount of after touch needed was less than I expected when reducing set set off from (about) 3 mm to 2 mm. The conventional method had resulted in key dip close to 11.5 mm for 2 mm set off. It is now down to about 10.8 mm. This is probably roughly what it was when it left the factory in 1925 judging by the original punchings.

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Re: Do pianists notice small changes in let off and aftertou

Post by Barrie Heaton » 09 Oct 2011, 18:46

Withindale wrote:
PS Thanks to increased jack angle, change in the point of escape around the curve of the butt, I found the amount of after touch needed was less than I expected when reducing set set off from (about) 3 mm to 2 mm. The conventional method had resulted in key dip close to 11.5 mm for 2 mm set off. It is now down to about 10.8 mm. This is probably roughly what it was when it left the factory in 1925 judging by the original punchings.

Ian

They will have compressed over time even at the ends I would say it was more 10 to 10.5mm dip, set off at 3mm checking at 15mm That was very common setting on 122 German pianos

Now as a comparison Alfred Brendel liked a 9mm dip and the checking as close as possible.


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Re: Do pianists notice small changes in let off and aftertou

Post by Withindale » 09 Oct 2011, 20:26

Thanks, I'll have another look at what key dip is possible but I'd rather not raise the hammer rail. It came with 40 mm blow but that had compromised its power. Fortunately the dampers had not been adjusted.

122 German = 1920s German?

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Re: Do pianists notice small changes in let off and aftertou

Post by Barrie Heaton » 09 Oct 2011, 20:37

122 is the hight of the piano

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Re: Do pianists notice small changes in let off and aftertou

Post by Withindale » 09 Oct 2011, 21:58

Mine is 140 if that makes a difference.

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Re: Do pianists notice small changes in let off and aftertou

Post by Barrie Heaton » 09 Oct 2011, 23:32

Yes taller pianos tend to have longer keys, so the key to hammer ratio is better.

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