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This is a nice collection thread to show different piano actions. So I would like to add this picture of a Steinway action.

hpeterh, thank you for your work. I think everybody understands that this is one aspect thread and it's good it is. For me this is enlightening and showing some answer WHY do we feel some things in action the way we do.

As an example, DPBSD thread helped me in understanding why some digital pianos sound dead for me, while grand pianos are so alive. That's because in most DP few corresponding keys share same sample, and they sound the same way. It's artificial in some way. In better sets, like Roland SN, every key sings its own unique voice. This was what I felt, and but didn't understood until listening some DPBSD samples. And more.
DPBSD is also thread that shows facts behind manufacturers sales speak aren't so great.

In this thread it's similar: simple physical fact proves, that DPs can't feel the same as acoustic, and it shows why. Also I felt many times going from digital to acoustic that keys feel different, specially in the way they travel - now I know and understand this simple reason; they are much longer on acoustic and "200% force" point is never used, while in DPs it's quite often.

And I see all DPs are deep enough to find other, more natural solution in key length aspect.

The illustration of key lever lengths and how they relate to touch-weight at various positions on the key has shed some light on an issue that has been troubling me.

I'm still a relative beginner, approaching my third-year anniversary of lessons. At home, I practice on a Yamaha YDP-223 digital (which has the GH action.) My teacher's piano is a 9' Steinway D. Those are the only two instruments I have any amount of experience on.

This past year, as my lesson pieces have become more "advanced", I've begun to have problems with tension in my playing, which leads to fatigue and soreness, especially in my right arm. What I found intriguing was I seemed to have a much easier time on the 9' grand than on the DP, my assumption being that the DP action should have been the lighter of the two. (Certainly in the bass, the Steinway does have more inertia in the key travel, but the treble feels much lighter than the Yamaha DP.)

I decided to measure the touchweight of my DP, and came across this article, which characterizes a typical piano as having ~50g down-weight, and ~20g up-weight. My DP has "graded hammers", but I measured only the lightest (treble) section, and found it had a ~70g down-weight, and ~50g up-weight. With 50g of up-weight, that's already more than double the force of a "normal" piano, required to hold a chord.

Taking into account hpeterh's observations about how the short keys in a DP multiply the required force: Playing high on a key (nearer to the fulcrum), I approach ~400% on the already-heavy DP, compared to only ~200% on the grand.

Knowing what I know now about the tough-weight of the DP action, it's no wonder that I'm having such a difficult time eliminating tension. (It's not for lack of trying either. I've been paying very close attention lately to posture and technique.) Maybe my next step will be to adjust my hand positions so that I'm playing as far down the keys as possible, closer to the "100%" zone.

Don't forget there is also dynamic weight of the keyboard. You measured static weight that is necessary to play the key. Dynamic weight is the way the keyboard responses to your playing with different force - for example it may appear as much harder when you play louder/faster, or otherwise.

Yes, right! This is only existing if a key has enough mass to transport from point a to point b. In my opinion this is very important to get a realistic action feeling.

A spring is not very helpful in this respect, just need a key with a specific length, and enough mass that will be moved by pressing down the key. The inertia is also important which is introduced by the mass and the to be moved distance.

On the acoustic forum, six footers would probably be called "parlour grands". (The p-word is sometimes spelled without the u.) Baby grands would most likely be 5'6" or shorter.

I'm enjoying this thread very much, tho struggling to understand it.

Hi, sorry for the revive, but those pictures posted by hpeterh are not visible anymore, does anyone recall the pivot lengths? Or at least...which digital action has the longest pivot length (besides the Kawai Grand Feel)?

EDIT: okay I see the pictures from web.archive.org, they are pictures of the action with the halfway point indicated with an arrow. Seems like the PHAIII length is longer than the RM3. Interesting... Just eyeballing it, the Celviano Grand Hybrid has longer keytops making it so that the pivot length is comparable to a baby grand, while the Roland is a hair shorter, and the Grand Feel is a hair longer. Of course, the Casio GP and Kawai Grand Feel have staggered pins for the black keys so those are actually a good bit longer. It seems only an Avantgrand/Grantouch, Casio Grand Hybrid, Kawai MP11/CA65/67/95/97/etc. will have something close to a real piano keyboard feel. I was not entirely happy with my Roland FP-7F with its PHAIII action for example and was not impressed with a Kawai MP10, but found the key length on the CA67 and Casio GP400 to be good.

I cannot see the images any more unfortunately. Have the links expired?

Yes, the original post was from 2010!

The post above yours suggests they were captured on the web archive wayback machine, so try that.

The approach in this thread seems rather unscientific.

Why don't we simply measure the travel of each model's keys in two places:
1. At the very end of the key.
2. At the opposite (fallboard) end.

I.e:

X = travel at #1
Y = travel at #2
Z = length of key from X to Y
Length to pivot = X / (X - Y) x Z

E.g:

x = 2
y = 1
z = 10

Length to pivot = 2/(2-1) x 10 = 20

x = 5
y = 3
z = 10
Length to pivot = 5/(5-3) x 10 = 25

|__Z__|________
X <-> Y___/
__/----


So these 3 measurements can all be made without needing to open up the key mechanism.

Sorry for the ASCII art

The problem is measuring Y accurately enough. Others have tried this and miscalculated the distance from the end of key to the pivot point.

I'll be using a laser measure

I'm away from my laser measure until November, so I'll report back then with pictures and measurements of:

Kawai CA78/CA98
Kawai Novus NV10
Yamaha NU1X
Yamaha CLP-685
Casio GP-300/GP-400/GP-500
Roland LX705/LX706/LX708

Plus anything new released between now and November.

I'll use a Fazioli F308 as my acoustic reference.

May the best pivot length win!

In that case...

That was me, I didn't have anything like the proper tool and I was almost a mm wrong which made a huge difference. I thought the distance to the pivot from the fallboard should have been 5 cm when it was 3.