http://home.kpn.nl/velo68/MBA_GB.pdf

And also the magnetic acellerated action  (page7):

http://www.petrof.com/files/rok_2008/pe...glicky.pdf

http://sheaf1.wpengine.netdna-cdn.com/w...piano4.jpg

EDIT: When the sustain pedal is not pressed, you have to lift dampers as well and that makes bass keys indeed a little heavier to depress.

A person there said the Grand Touch short action do not make much diference compared to good digital hammer action piano, just have the wood and scapment.

I understand that 100 years ago piano manufactures dreamed to eliminate scapment "clic" and get a uniforme weight along the entire keyboard from bass to trebble.
Some people use this as argument to say that we don't nedd scapment or graded keysboard...

But people play in real pianos today, especially in important events, and a digital piano with real piano sensation helps to have same ability, or be prepared to the imperfections of real pianos.

regards,
Sebastian

9 foot:

6 foot baby grand:

Upright:

Kwai MH3:

Roland PHAIII:

Yamaha  GH :   

Grand Touch:

Avantgrand:

Is the 200% point really so important , or just a small extra confort ???

If it's really important, I supose Bosendorfer Ceus digital was said to have the longest action, so I supose it have the better 200% point of all digital pianos.

See how the space from the keys edge to the center of balance (with pins), are shorter in Yamaha Grand touch?

Yamaha Grand touch:

Traditional grand piano action:

Upright action:

Yamaha Grand Touch also have the hammer's arm support (golden in the picture) closer to the center of balance (pins).

Welll.... my question:  Is this Yamaha Grand Touch "shorter" action similar to a real piano action of some piano brand, or no grand piano action is shorter like this?
If it's really shorter than all grand piano actions, does it make difference for play?

I've tested the NU1. The action feels nice for an upright but it the internal sounds especially through the internal speakers suck. I didn't test it with pianoteq though.

@gravity sheets: I had this idea, too some time ago, but I don't think it'd work. Like I said you can compensate for the  non constant reset force by a spring, but this spring has to have exactly the right stiffness and it will raise the friction at the jack-hammer butt link and might lead to unwanted behaviour.

regards,
Sebastian

I think we can solve this problem instaling a horizontal gravity sheet near the hammers.

Háa háaa háaa...

Ok, seriously speaking... When someone get the chance to test Yamaha NU1 Avantgrand Digital Grand Hybrid Piano, please get to this topic and report about the key sensibility, if it's better or not than most digital piano compact hammer action system.

Yamaha vertical action:

Hey, wait a minute...
The gravity sheet (Sci-Fi joke) got me a idea...
If we replace the springs for gravity (transfered from vertical to horizontal by some sort of a pulley with some lead weight) maybe it work better.

You are correct:  Upright actions are less sensitive and less playable than (quality name-brand) grand actions for one main reason -- grand piano actions utilize the force of the earth's gravity to reset the hammers and keys.  Upright piano actions require extra linkages and springs to make up for gravity not being of much help in this regard.

Think of the string layout on a grand piano -- the strings are positioned horizontally, and the felt-tipped hammers strike the strings from below, and the earth's gravity helps pull them away from the strings, and reset the double escapement action. 

Contrast the horizontal string layout of a grand piano with that of the VERTICALLY aligned strings in every upright piano.  The upright's strings run parallel to the pull of gravity, so where does that leave the hammers?  The hammers strike the strings essentially horizontally; gravity plays no part in retracting /resetting the hammers of an upright piano.

Upright pianos require an elaborate connection of springs and cloth strips to help pull the hammers away from the strings and reset the escapement, so the notes may be played again. Upright actions also require more linkages (and associated friction points and reduced sensitivity) than grand pianos' actions.

When playing repeated notes on a grand piano, one does not have to wait for the key to return completely to its most upright position.  (That sounds like a statement heard by an airline stewardess!!  I digress.)  Unless you are playing a high-end, brand name upright piano, one cannot play quickly repeated notes, because the keys must return completely to their original positions.   

I hope this helps clarify some of the differences between grand- and upright piano actions.

Cheers,

Joe

I believe that is not entirely true:
- a grand piano action is 'reset' from escapement by a spring at the repetition lever that holds up the hammer as long as the jack is not under the 'hammer roll'(I don't know if it is called that way in english), but it is true, that the hammer as well as the entire mechanism is pulled down by gravity in a way that leads to a nearly constant reset force. That makes it less likely for the hammer to jump around and leads to the often called 'more direct' touch of a grand action. There are some rare upright actions that have an additional repetition spring that does the same for an upright action, but these springs make the action more time consuming to regulate.
- A grand piano action has far more parts as an upright one, and I don't think an upright action has more linkages that induce friction(but I'm always happy to learn): for an upright you only have the linkage capstan button - action lever and the linkage jack - hammer butt. Of course you have the friction of the axes, too, but the number of axes is speaks more for the upright action rather than the grand one

so lets come to the faults of an upright action:
due to the hammers nearly vertical position you get a hammer reset force that depends on the hammers position. It is proportional to the hammers weight multiplied by the sine of the angle  between a line that goes through the hammers center of mass point and its fulcrum point and a vertical line going through the fulcrum point(just think of the angle of the hammer against its vertical position, that is a good approximation). Since the hammer has a way of motion of lets say less than 30 degrees you will find sin(x) ~ x a good approximation for the hammers reset force. That means, even when you take away all springs(as seen on many >100 years old upright actions) you get the opposite of a a-spring like reset force for the hammer. This means depressing the key gets easier the more you depress it, if you don't have any springs present. On modern piano actions you have springs at the hammer butt that will partly compensate for this behavior, but this is not entirely possible because a tighter spring will induce more friction.
You can easily observe this fact when sitting at an upright and weighting the keys with coins while the sustain pedal is depressed. just put an amount of coins on one key that is barely not enough to depress it. then you can depress it by about 1-2 mm and you will see the key move down to the trigger point. This non constant reset force of a hammer makes it more probable for the hammer to jump around, being reflected at its rest position when you play very short staccato notes that prevent the hammer from being caught by the catcher. In an upright action aprox half of the reset force comes from  the weight of the action lever, that is attached to the hammer by a bridle tape in order to tame this free bounce of the hammer leading to a more regular touch with repetitions.
I think one more thing should be mentioned: an upright action can be reset to be able to repeat a note without having to let the key go up the full way. In fact it can repeat as fast as a grand action, but only if the preceding note is held long enough for the hammer to get caught. If it is not caught you have to let the key go up the full way. You will notice the bad repetition behaviour of an upright when playin trills.

My text has become much longer than intended, but I hope I have made my point

regards,
Sebastian

[...]
  Isn't all upright piano action less sensible or playable than grand piano actions???

Hello Beto-Music,

You are correct:  Upright actions are less sensitive and less playable than (quality name-brand) grand actions for one main reason -- grand piano actions utilize the force of the earth's gravity to reset the hammers and keys.  Upright piano actions require extra linkages and springs to make up for gravity not being of much help in this regard.

Think of the string layout on a grand piano -- the strings are positioned horizontally, and the felt-tipped hammers strike the strings from below, and the earth's gravity helps pull them away from the strings, and reset the double escapement action. 

Contrast the horizontal string layout of a grand piano with that of the VERTICALLY aligned strings in every upright piano.  The upright's strings run parallel to the pull of gravity, so where does that leave the hammers?  The hammers strike the strings essentially horizontally; gravity plays no part in retracting /resetting the hammers of an upright piano.

Upright pianos require an elaborate connection of springs and cloth strips to help pull the hammers away from the strings and reset the escapement, so the notes may be played again. Upright actions also require more linkages (and associated friction points and reduced sensitivity) than grand pianos' actions.

When playing repeated notes on a grand piano, one does not have to wait for the key to return completely to its most upright position.  (That sounds like a statement heard by an airline stewardess!!  I digress.)  Unless you are playing a high-end, brand name upright piano, one cannot play quickly repeated notes, because the keys must return completely to their original positions.   

I hope this helps clarify some of the differences between grand- and upright piano actions.

Cheers,

Joe

http://www.production-room.com/yamaha/y...rid-piano/

Funny, in my idea of a real grand piano action MIDI controller, I was imagining some glass to show the hammers moving.
In this upright the glass make it quite nice.

I supose it is more adequate fur small spaces, as a upright action do not take space like a grand piano action.

But....   Isn't all upright piano action less sensible or playable than grand piano actions???

What is the best piano action after all, Renner or Kawai?

By the ray, the performance, for a video demo of Renner1s action, it's great.
http://www.youtube.com/watch?v=9dEOqU_Y-4A
Does anybody knows what music is that?

Steinway action  http://www.youtube.com/watch?v=01DBtig_...re=related
Se the scapment in action.

By the way, I'm curious about the scapment in case of PNOscan or home made MIDI sensor.  How to adjust the sensor to do note produce key sound (send message to software) before the scapment "clic" ?

In this video explaination about piano action, we get give a good idea of how large a action controller case would be.
http://www.youtube.com/watch?v=6qA_sHa9...re=related

I think both actions are pretty good (when in good shape, of course). I suppose KAWAI action might need some less maintenance with their carbon parts.

regarding the escapement click or trigger point, yes this can be setup for in these sensor bars. You need well regulated action, so that the trigger point is at about 2/3 of the way. As the sensor bar knows what the entire way a key travels is it is setup to have the trigger point at 2/3 of that way.

By the ray, the performance, for a video demo of Renner1s action, it's great.
http://www.youtube.com/watch?v=9dEOqU_Y-4A
Does anybody knows what music is that?

Steinway action  http://www.youtube.com/watch?v=01DBtig_...re=related
Se the scapment in action.

By the way, I'm curious about the scapment in case of PNOscan or home made MIDI sensor.  How to adjust the sensor to do note produce key sound (send message to software) before the scapment "clic" ?

In this video explaination about piano action, we get give a good idea of how large a action controller case would be.
http://www.youtube.com/watch?v=6qA_sHa9...re=related