Actions compared -updated

Posted by: hpeterh

Actions compared -updated - 10/28/10 02:01 PM

I added some important brands and so I repost this.


Be aware, that it doesnt matter where the hammer is, if you look to the physics of a lever.
The 200% arrows are as accurate as I could do.
This is exactly the middle point between pivot axis and keyfront.
Fatar TP100 looses definitely. It is however, only a small difference so go into the next musicstore and try out, if this matters to you


The real Grand Piano is -of course- the absolute winner.

Unknown grand piano Model. I think it is a 9 foot model.
Taken from website of german piano industry association.
http://www.pianos.de/de/das_instrument/index.php?id=20
Force-arrows in all images added by me.

Kawai Grand - unknown model. I think it is a 6 foot model.
Keylength compares to a Yamaha G2 5'7 Baby Grand, I checked this.

Upright - unknown model

Kawai RM3

Kawai RH3

Casio Tri Sensor

Fatar TP40W (NUMA Nero)

Fatar TP 100 LR (Numa Piano)

Roland PHAIII

Yamaha GH



I find this is a much more important criteria to compare a digital action to a grand piano action.

Heavy and graded weighting is something that the piano builders fight. They try to minimize it.
They try to maximize keylenght.

So the advertising arguments that are sometimes given to unknowing people are somewhat misleading.

No DP reaches a grand and most dont even reach a lower class upright in keylength.

So many DP's just combine the disadvantages of a Grand -heavy grading and weighting- with the disadvantage of an upright - short keys.
This is then advertised and sold as a accurate modelled grand action. They all tell lies to their unknowing customers ;-)

Yes they all try to get a good touch and feel, but none of them tries seriously to emulate the most important and basic and obvious physical parameters of a grand action accurately, because thats too expensive.

Because grading and weighting are also attributes of uprights, (and match much better) the comparison to a grand is nothing else than intentional misinforming advertising.
Posted by: hpeterh

Re: Actions compared -updated - 10/29/10 01:12 PM

OK, finally I found a high res image of the Yamaha GH action here:
http://www.yamaha-europe.com/picture_archiv/products/10_Musical_instruments/Others/

From this it turns out that the differences between the big manufacturers Yamaha, Roland and Kawai are almost neglectible.
There is only one clear looser: Fatar TP100. Casio is only lightly better.
Therefore I removed all other comments.

Edit: If it comes however to the length of black keys, then Kawai RM3 wins definitely because it has a shifted pivot point.
This is not visible here.

Peter
Posted by: ChrisA

Re: Actions compared -updated - 10/29/10 01:58 PM

I'd bet you could make a good digital action with zero length keys. Length may matter if the hammers have to strike strings but thy don't on a DP. One way you could build a DP is to use electric linear motors under the keys and the moors could produce force to simulate any kind of action. This was actually done (I lost the refference buy Google can find it.) They made the elxtonic key, then "sampled" the pressure from variious pianos actions and could simulate in near perfectly. This would be great because you could have your keys feel like any piano (or organ) you like. The trouble is the cost, more then the cost of a current DP for each key. Maybe if it were mass produced it could go down to only a few hundred dollars per key, but you need 88 of them.

In the past some DPs used oil dampers so simulate key mass or I should say "the mass of the moving parts in the acton" this worked but they found cheaper and more reliable methods.

I think also that we are turning a corner. Look at Yamaha's new "Stage-NW" keys. I think they've decided not ot even try to emulate an acoustic piano. Most of the people who buy the DP will use that DP as their performance instrument on stage and will never play an acoustic piano. Over tie more and more people will stop comparing a DP to an Acoustic Piano.
Posted by: JFP

Re: Actions compared -updated - 10/29/10 02:14 PM

@hPeter; exellent work, but I don't unstand what we are looking at here. Perhaps I missed some previous threads with explanation, but could you please describe what we are seeing here in this comparison with pictures and which one is better than the other and what the perfect target should be ? It would make things easier to understand. Thanks
Posted by: hpeterh

Re: Actions compared -updated - 10/29/10 02:25 PM

The initial image explains it.
I look solely to this singular and measurable aspect of relative key-lever length, no other aspects are covered here.
I do however assume that the visible length of piano keys is standardized and therefore comparable. I am unable to measure and compare this using images only.


Peter
Posted by: JFP

Re: Actions compared -updated - 10/29/10 04:50 PM

I must be dumb and stupid, but since I have no clue as to what you are showing here, it's hard for me to read and understand the picture and the 200% arrow that you put in each one.

Does this mean that the 200% fingerforce point should be shifted backwards (from you) as far as possible and that 100% is the ideal striking force ? And that keybeds that are not so good have their 200% point more on the front of the key , which gives a unnatural and heavy response ?

As far as I can see the 200% arrow is all in roughly the middle of the key, so am I missing the point you're trying to make here ?

Pitty that some brands have no better pics posted , as with the Casio keys and FATAR's. I already found that strange in the past when I was looking for a DIY way to build a piano - which I later abandoned. (For the manufacturer: if these pics are hardly readable why post it at all...)
Posted by: sullivang

Re: Actions compared -updated - 10/29/10 05:27 PM

Originally Posted By: ChrisA
One way you could build a DP is to use electric linear motors under the keys and the moors could produce force to simulate any kind of action. This was actually done (I lost the refference buy Google can find it.)


Yes, and we've already discussed it HERE in another thread:
this thread

Greg.
Posted by: hpeterh

Re: Actions compared -updated - 10/30/10 05:15 AM

Originally Posted By: JFP

As far as I can see the 200% arrow is all in roughly the middle of the key, so am I missing the point you're trying to make here ?


Yes, thats true. You must look to the relative dimension of the black key. This is not equal.
(I assume that the real absolute dimensions of the black keys is mostly identical because this is standardized. Of course I cannot measure this using these images)

The images are scaled this way that the key lever length is identical. There is no other way for comparison without having the real absolute dimensions.
Also look to this posititon where the white touch surface ends.
This is also unequal.
There is some guesswork and eyeballing necessary, but I think, it can be seen there is a large difference between the real grand and the digitals.

And for the white key there is not much difference between Yamaha Roland and Kawai.

However, Kawai's RM3 has a longer lever for the black key than the others. This is not shown or discussed here.
That said, I am not too much concerned about the length of the black keys. These are easy to hit and depress. The difficulty is to play the white keys inbetween of the black keys. I dont understand why they didnt shift all pivots ....


Best,

Peter
Posted by: anotherscott

Re: Actions compared -updated - 10/30/10 08:48 AM

Originally Posted By: hpeterh
I am not too much concerned about the length of the black keys. These are easy to hit and depress. The difficulty is to play the white keys inbetween of the black keys.


Actually, I find the bigger issue to be on the black keys (at least on some semi-weighted keyboards I've played, where I've noticed it the most), and I think your diagram demonstrates the problem.

Play an Eb chord, then play an Eb minor chord... you'll probably find that, on the minor chord, your middle finger kits the key much closer to its rear end. At that point, on some key designs, you're quite close to the pivot point, and the amount of finger force required to get the same volume is much higher.
Posted by: theJourney

Re: Actions compared -updated - 10/30/10 09:04 AM

The Korg SP-200 that I have suffers from this problem. The force required on the back half of the keys is much greater than at the front and difference for the black keys in particular is dramatic and unrealistic compared to the force required on my Kawai RX-2
Posted by: theJourney

Re: Actions compared -updated - 11/05/10 04:11 AM

http://www.pianoworld.com/forum/ubbthreads.php/topics/1551287/1.html

Action geometry is an interesting subject...
Posted by: bennevis

Re: Actions compared -updated - 11/05/10 08:14 AM

Surely the deciding factor is what the key action feels like to the performer? Even grand piano action differs between different makes, and I don't just mean the weight of the keys. And of course uprights feel totally different to grands. I find that my V-Piano's key action is closer to a concert grand's than most uprights are.
Posted by: hpeterh

Re: Actions compared -updated - 11/05/10 01:54 PM

Yes, but I do not want compare cherrys to oranges.
I want to look to the differences between them.
Not all grandpianos are created equal.
Not all upright are created equal.
But most digitals have something in common.
Therefore I updated my images for better clarity.
See above.
Posted by: hpeterh

Re: Actions compared -updated - 11/06/10 08:54 AM

Ok, it was doubted that the first image shows the real dimensions of a real grand keybed.

Now watch this Petrof Grand being disassembled and look shortly after 1:00. If you want, stop the video and measure it ;-)

Also visible here:
Posted by: Erard

Re: Actions compared -updated - 11/06/10 03:18 PM

Peter,
thank you for all you effort to demonstrate a VERY important parameter in piano action.
In my experience, the longer the distance of the fulcrum the better the action feels while playing. One of the reasons, as you point out, is a better uniformity of the weight along the key.

I would add to that also a better uniformity in key travel distance. If the fulcrum is too close, when your fingers get closer to the fallboard, not only the weight increases but also the key travel decreases and it gets very difficult to properly control the timing and the intensity of the sound.
For example, when you play octaves with your right hand below the center of the keyboard on the black keys (1-4 fingering) the fourth finger gets naturally very close to the fallboard. The same happens on the white key between the sharps when you play four notes chords like Eb7.

In the case of the octaves I described, on my P90 the thumb gets a travel of approximately 9mm while the fourth finger has only 3,5mm (plus a much higher key weight) - VERY difficult to play the two notes perfectly in sync. I can feel my hand getting rigid and tired from the effort. This is much easier to play correctly on the C3. And even better on a real grand.
I think we are very, very far, on almost all the DPs, from the keyboard quality and experience of a grand action.
Posted by: sullivang

Re: Actions compared -updated - 11/06/10 04:18 PM

Yes, thanks Peter - I had never really thought about all this at all. It's a bit depressing that DP makers seem to have paid so little respect to the grand's action for so long! I now have a full appreciation of the advantage of the offset fulcrum points in the Kawai RM3 action.

Greg.
Posted by: hpeterh

Re: Actions compared -updated - 11/10/10 02:38 PM

Ok I have reached the limit of images so I need to add another post.
I believe this image is worth it.

This is the action of the Yamaha Gran Touch GT1.
Surprisingly the 200% location is very similar to other digital pianos.
So when this action feels so much better then there must be another factor thats important: The overall leverage ratio Key-hammer.
This is 3 or less for most digitals. Unfortunately it is not precisely visible from this image, but for large grands it is up to 6.

This ratio is the ratio between weight and massinertia (if the keys mass is neglected)



BTW, it seems to me, pianists are a little bit like the princess and the pea when it comes to the feel of the action. Im now asking myself: does this all really matter?




Of course it is pure Nonsense to compare any digital -including the Gran Touch- to a larger Grand Piano...
Baby grands have longer keys.

Look here a Kawai six foot CA60. You see the length of the keys at 1:40 for a very short time.


It is rewarding to look into this guys channel because he shows off the action of many pianos that he has for sale.
Posted by: theJourney

Re: Actions compared -updated - 11/11/10 04:06 AM

Keep 'em coming! This thread is great.
Posted by: hpeterh

Re: Actions compared -updated - 11/14/10 11:14 AM

There is another thread on pianoworld that shows an image of the AvantGrand opened.

Unfortunately the Balance point is not visible but it is clear thats another Class and not comparable to RM3 and Grandtouch.



Taken from
http://www.pianoworld.com/forum/ubbthrea...20N2%20apa.html
Posted by: FogVilleLad

Re: Actions compared -updated - 11/14/10 02:43 PM

Originally Posted By: hpeterh
Of course it is pure Nonsense to compare any digital -including the Gran Touch- to a larger Grand Piano...
Baby grands have longer keys.

Look here a Kawai six foot CA60. You see the length of the keys at 1:40 for a very short time.
Manufacturers usually fit longer keys to their models at approximately their seven feet long models. (The CA 60, for example, is said to be 6'10".)

Originally Posted By: hpeterh
This is the action of the Yamaha Gran Touch GT1.
Surprisingly the 200% location is very similar to other digital pianos. So when this action feels so much better then there must be another factor thats important: The overall leverage ratio Key-hammer. This is 3 or less for most digitals. Unfortunately it is not precisely visible from this image, but for large grands it is up to 6.

BTW, it seems to me, pianists are a little bit like the princess and the pea when it comes to the feel of the action. Im now asking myself: does this all really matter?
It does matter, but ultimately people have to choose based on how an action feels to them. That decision will be influenced by their previous playing experience - and budget, of course!
Posted by: sullivang

Re: Actions compared -updated - 11/14/10 06:46 PM

For the key length (and hence, key movement) aspect, I guess there are two aspects:

a) How long, in absolute terms, do the keys have to be for a human to play very advanced material?

b) How long do the keys have to be in order for a concert pianist to be able to easily switch between a concert grand and the other keyboard, that has shorter keys?

I.e - perhaps the key lengths in an upright are ENTIRELY adequate, and the only reason they are longer in a large concert grand is simply because they HAVE to be, in order for the pianist to be able to have enough leverage to play loud enough.

Greg.
Posted by: hpeterh

Re: Actions compared -updated - 11/15/10 04:10 AM

Greg,

Hammers are usually placed at 1/5 to 1/7 of string length.
They are placed this way that the 7th harmonic is almost surpressed.
Thats another reason for the keys being longer.

For a nine foot the keys are about 30% longer than for a 6 foot for this reason.

I believe anybody should be happy with the keylentgh of a 6 foot baby grand, but no digital -including the Gran Touch- does reach this.

With uprights the pianodesigners have more degrees of freedom for the keylength.
Maybe we should look to the keylength of uprights that are commonly aknowledged for their action to get a reasonable measure about this.

Peter
Posted by: mucci

Re: Actions compared -updated - 11/15/10 04:31 AM

Hmmmm... I don't see the point by mainly focusing on the keylength as a major criterium for realism of keyboard action. According to your interesting illustrations I don't see a lot difference in pressure, except for the grand. Don't forget that long keys also have some downsides, e.g. it might take longer for the keys to release back to the starting position due to a different inertia depending on mass. I think there are a lot more criteria that are even more important than a little bit more or less keylength.
Posted by: sullivang

Re: Actions compared -updated - 11/15/10 04:37 AM

Why do longer keys take longer to return? How can you be so sure?

I don't know how important or unimportant the key length is - as I said before I had never even thought about this at all. I'm glad the topic has been raised! smile

Greg.
Posted by: mucci

Re: Actions compared -updated - 11/15/10 05:14 AM

Originally Posted By: sullivang
Why do longer keys take longer to return? How can you be so sure?


I said depending on mass. And yes, it's an interesting thread, but a little one-sided.
Posted by: hpeterh

Re: Actions compared -updated - 11/15/10 05:53 AM

When the mass increases the resonance frequeny goes down.
The amount of bounce back energy increases.
When the elasticity of the felts become stiffer , the frequency goes up again, but the forces needed will be higher.

Therefore keylength does not necessarily make the action slower, but increases mass inertia and forces.
That are the physical facts.
Posted by: sullivang

Re: Actions compared -updated - 11/15/10 06:23 AM

According to my piano tunining book, the better pianos have counterweights that are located between the centre rail and the capstans.

Greg.
Posted by: hpeterh

Re: Actions compared -updated - 11/15/10 06:44 AM

Yes.
A counterweight thats near to the center balance does not increase mass inertia much. (This is why the weights are placed this way)

If a 5 gramm weight is placed 20 cm from center and a 10 gramm weight is placed 10 cm from the center then both have the same effect on weight. But in that case the 10 gramm weight has less effect on inertia than the 5 gramm weight ;-)
This can be calculated with some physics, but any pianotechnician can confirm it.

A little bit of key inertia might be wanted for comfort of touch, it can buffer the hammer bounce, but anything more than that is generally unwanted and fighted by piano builders.

In modern designs the weights are replaced by magnets.
Because these dont cause inertia they can be placed at the hammer where they are far more efficient because there is more leverage effect. The inertia must be located in the hammers and the pianist wants to feel the hammers inertia at the key touch surface.
Posted by: JFP

Re: Actions compared -updated - 11/15/10 02:50 PM

Can I ask (without being punished) ; after all these pictures , measurements and explanations - do you have a short list of the keybeds that are used in DP's from best to worst ? E.g. how do PHAII, PHAIII, RM3, RH, GH3, Tp40Wood etc meassure up to your 'ideal' grand piano keybed. It think that might be very interesting for potential Dp buyers to know.

Thanks
Posted by: hpeterh

Re: Actions compared -updated - 11/15/10 03:06 PM

JFP,

short answer - no.
I just want to know the technical criterias,thought a lot about it, recherched about it, experimented with it, and finally calculated the physics, got some results and want to show them.

Ok, let me rethink - most probably the Avant Grand is the best digital ;-)

Peter

Posted by: spanishbuddha

Re: Actions compared -updated - 11/15/10 03:11 PM

Originally Posted By: hpeterh
JFP,

short answer - no.




Yes I agree. It's interesting stuff, a bit like a mechanical DPSD for the actions.

But it doesn't tell you how well the key action is integrated with the sound generation and response system; in other words the playability.
Posted by: MacMacMac

Re: Actions compared -updated - 11/15/10 04:09 PM

I wonder whether all of this demonstrates anything at all.

Can I decide whether I'll find a piano suitable based on pictures and percentage forces and key lengths? I doubt it.

The old saw still holds ... you have to try the piano before you can know how it feels.
Posted by: hpeterh

Re: Actions compared -updated - 11/15/10 04:32 PM

Originally Posted By: MacMacMac
I wonder whether all of this demonstrates anything at all.

Can I decide whether I'll find a piano suitable based on pictures and percentage forces and key lengths? I doubt it.

The old saw still holds ... you have to try the piano before you can know how it feels.


This is exactly what it says.
The geometrical and physical parameters of all digitals are very similar and cannot be taken as a decision criteria.
The differences are minuscle compared to the differences that are between acoustics.

Exceptions are the count and placement of sensors, this is not investigated here.

The GranTouch apparently has more realistic inertia and only the Avantgrand is close to a 6 foot Baby Grand or possibly better in geometry and mass distribution.
Posted by: Strat

Re: Actions compared -updated - 11/15/10 04:47 PM

Originally Posted By: hpeterh
The geometrical and physical parameters of all digitals are very similar and cannot be taken as a decision criteria. The differences are minuscle compared to the differences that are between acoustics.

Exceptions are the count and placement of sensors, this is not investigated here.

It'd be interesting to investigate this second matter in a different thread.

Though this one has been quite interesting, I too figured that the differences wouldn't be as drastic as some people make it sound. There is a difference in how it feels, but to suggest that one keybed requires much more weight to play didn't sound right to me.
Posted by: dewster

Re: Actions compared -updated - 11/15/10 05:02 PM

Originally Posted By: MacMacMac
Can I decide whether I'll find a piano suitable based on pictures and percentage forces and key lengths? I doubt it.

You can't deny that the pivot point location is a very fundamental element of the key action feel. As such, you can you ignore it at your peril, though perhaps this is something one unconsciously factors in when demoing keys? Still, it never hurts to know what physically or electrically corresponds to what we aesthetically approve or disapprove of.

If someone made DP keys with a pivot point more like that of a real grand, yet didn't weight a ton, I would certainly sit up and take notice.
Posted by: hpeterh

Re: Actions compared -updated - 11/16/10 02:15 PM

After long research - here is it ;-)



So it is not so very much different from the GranTouch as I believed. Also the difference against the better digitals is there but it is not drastic.

This should eqal an action of a 6 foot Baby Grand.

So be happy, whatever digital you might have, play it ;-) , the action parameters are only shortly below the Avant Grand.
grin
Posted by: dewster

Re: Actions compared -updated - 11/16/10 02:24 PM

Originally Posted By: hpeterh
So it is not so very much different from the GranTouch as I believed. Also the difference against the better digitals is there but it is not drastic.

I'm somewhat disappointed with this discovery. I thought AG keys were the holy grail of DP feel, and now we see that they could be improved.
Posted by: hpeterh

Re: Actions compared -updated - 11/16/10 02:32 PM

grin sick blush crazy tired wink
Posted by: MacMacMac

Re: Actions compared -updated - 11/16/10 02:43 PM

Originally Posted By: dewster
You can't deny that the pivot point location is a very fundamental element of the key action feel. As such, you can you ignore it at your peril, though perhaps this is something one unconsciously factors in when demoing keys?
There's no peril in ignoring what's hidden "under the covers." A pianist only touches the parts above the covers.

By playing the piano, anyone can decide for himself if the feel is right. In contrast, you cannot make any such determination just by looking at the 200% point on the diagrams. So what's the point?
Posted by: hpeterh

Re: Actions compared -updated - 11/16/10 02:49 PM

Curiosity is the point. I want to know it.

When I do something, I always want to know how it works.
When I was young I was more interested to look into the TV, than to look onto it and that has not changed ;-)

BTW, the image is taken from here:
Posted by: Upright

Re: Actions compared -updated - 12/31/10 07:33 AM

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

Posted by: kiedysktos.

Re: Actions compared -updated - 12/31/10 09:35 AM

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.
Posted by: Voltara

Re: Actions compared -updated - 01/03/11 01:57 AM

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.
Posted by: kiedysktos.

Re: Actions compared -updated - 01/03/11 09:24 AM

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.
Posted by: mucci

Re: Actions compared -updated - 01/03/11 10:50 AM

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.
Posted by: FogVilleLad

Re: Actions compared -updated - 01/03/11 02:28 PM

Originally Posted By: hpeterh
This should eqal an action of a 6 foot Baby Grand.
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.