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Any opinions on the following measurements obtained on a new piano that I am considering?

C1
DW 52
UW 30

C2
DW 51
UW 29

C3
DW 50
UW 30

C4
DW 51
UW 30

C5
DW 49
UW 26

C6
DW 47
UW 27

C7
DW 49
UW 26

C8
DW 48
UW 33


And then compared to another preowned piano that I am also considering:


A2
DW 49
UW 34

A3
Dw 51
Uw 34

A4
Dw 51
Uw 34

A5
Dw 49
Uw 32

A6
Dw 49
Uw 33

I could make two actions with the exact same geometric design of leverages and rotational interfaces that would measure DW and UW exactly the same.

However when you went to play them they would feel totally different.

Leaving aside any hammer felt density driven tonal differences between the two, it is the inertia differences that you will notice first.

Informed technicians know that DW and UW are only good for deriving the friction in the action, and measuring relative evenness from note to note.

One of our long time PW posters ROY123 has done some excellent research proving that it is the hammer that is the most significant factor in setting the inertia feel of an action.

Starting in the early 1980's I developed a tone regulation protocol I named: LightHammer Tone Regulation, that uses the inertial feel of the action to derive the hammer weight.

Check out this thread. Lots of thoughts on touch weight in general, and a few people included their measurements. There's also been lots of other discussions about this if you do some searches.

Out of context the first is excellent and the second has too much UW. However, in context both pianos could be good, bad, mediocre etc etc and either could feel and respond significantly better than the other.

I'm of the opinion that in almost all pianos, there is never too much up weight. Up weight helps the action reset quickly, and helps the pianist raise his/her finger from the key. I think pianists think up weight shouldn't be too high because they're used to playing pianos with lowish up weight. I bet a few weeks practicing on a piano with what would be considered high up weight would make believers out of most of them.

The pianos I have played with what I consider too much upweight allow for extremely fast single note playing but the more chordal the playing the more difficult they are to control especially at lower volumes. If they were corrected to an upweight I consider normal, they felt and responded much better.

You can adjust somewhat but I think at no point does the extra effort and limitations of chordal playing go away. Any piano that is off can be managed better as one adjusts, that doesn't mean it is right.

With that being said, even though I have some very clear parameters for what will get predictable results and enthusiastic responses from pianists with highly developed healthy piano techniques, I have been surprised in the past in playing pianos that I liked whose "numbers" were quite different from what PianoCraft thinks is correct.

I am not surprised when I play a piano with an action that has lower DW and UW than my LightHammer Actions; and I find things that I like about it if it is voiced well.

What I do find is they are harder to control when playing softly and I get tired trying to play fast on them.

What I do know is actions made with lower inertia than is common endure significantly better over time, and are more stable in regulation.

This makes the ownership cost of a fine piano much, much cheaper over time.

Is there a way to calculate inertia?

I have a Pitchlock Touchrail on order, which will let me reduce my downweight by a preset amount. I figured I'd try 5g, which will reduce my average downweight from about 52g to 47g. My front key leads are about 3-4 inches from the front of they keystick. I figure the 5g reduction in DW will let me pop out the front lead on each key, thus increasing my UW by a few grams. I'll let you how that affects the feel of the action, ability to play softly, etc. I'm hoping the resultant decrease in overall inertia and spring assist with the breakaway inertia will help my piano achieve Ed's LightHammer feel, which I've always been intrigued with.

Emery,

I'm glad you are going to try this. I would like to suggest that that initially adjust it to just barely take the "edge" off the static friction issue at breakaway. Try that for a while...then increase if needed. I'm interested to know how you like it.

Peter Grey Piano Doctor

Thanks Peter. I really think overcoming the inertia of the hammers and key leads will help the feel. I use my Kawai MP11SE digital as a comparison: although it has a slightly higher DW than my acoustic, the action feels noticeably lighter to play. The keysticks are also wood in the digital, but there are no leads in the keys. Likely this is because there is less weight on the rear of the keystick to overcome than there is in my acoustic. The result is it's easier to play fast passages and soft passages on the digital because there is less breakaway inertia to overcome at the start of the key movement, and inertia overall. However, fast repeated notes don't work as well on the digital as they do on the acoustic, likely because of the lower upweight.

If my theory is correct, the Touchrail should address the initial breakaway friction, and the removed key lead should reduce the inertia. But as you suggest, I will go with the least amount of spring pressure at first to see how it works.

Thanks for the advice, I'll keep you all posted.

I don't care for spring loaded actions.

And Emery, you will still need to come play one of my pianos to experience a LightHammer Action.

But I do hope you enjoy playing your piano.

Thanks Ed. I do hope to make it to NW WA after the pandemic. Maybe in the summer, I need to take the family to San Juan Island one of these days.

I admit the spring loaded key stop rail seems a rather simplistic way of controlling touchweight. Does it do something to the feel of the action you don't like?