Stanwood Piano Touch Weight Metrology™ [sc_embed_player volume=”50″ preload= “true” autoplay=true loops=”true” fileurl=”http://masterpianotuner.com/audio/_metrology.mp3″]
I was fortunate as a young man to be accepted into the North Bennet Street School (NBSS) Boston MA, Piano Technology Program by Bill Garlick the Piano 
Technology Program Director (department head) then at North Bennet. As all the good gifts we enjoy in this life I spent the following seemingly brief semesters among many talented young piano technology students at the North Bennet Street School which also included a then young David Stanwood, friend, colleague, and classmate that same year at North Bennet, technology program for piano. Stanwood is now also a long time North Bennet Street School Alumni.
Mr Stanwood, over many years, has placed a great deal of time and effort into his craft career and love for pianos.
This is about Stanwood Inovation Inc, Piano Touch Weight Metrology, a wonderful video presentation.
Mr Stanwood starts out by saying
My name is David Stanwood, President of Stanwood Piano Innovations.
Our shop is on Martha’s Vineyard, in the town of West Tisbury.
I’ve always had a passion for pianos, always loved pianos.
narration
David Stanwood’s passion for pianos lead him to question why even on some of the worlds best instruments the feel of the keyboard was sometimes inconsistent from note to note.
While training to be a piano technician at Boston’s North Bennet Street School Mr. Stanwood asked what could be done to improve pianos who’s actions didn’t feel right.
Stanwood
And the answer was, well-a – that’s not that easy.
So there really wasn’t an answer. That drove me to experiment and discover.
narration
The science of weights and measures is called Metrology.
Mr Stanwood’s quest lead him to develop a fundamental system and methodology for balancing piano action, something he called “the new touch weight Metrology.”
Stanwood
What was missing in pianos, was a metrology which explains the balance of piano actions in a whole way.
narration
Unlike a violinist who can carry his or her whole instrument on tour, the concert pianist must travel from hall to hall, playing on a variety of instruments, often with inconsistent playing action.
Stanwood
The equality of the mechanism of the piano can either act to support the pianist or it can act as a barrier to their art, and my quest has been to discover now what is the mystery in that mechanic of that keyboard what happens between the musical thought and the finger where it touches the key and the sound that comes out.
There’s a lot of stuff that goes on in this mechanism and that really shouldn’t be an issue for the pianist, they should have a thought and should be able to think it and express it in sound.
narration
The piano keyboard is a system of stepped weights. The hammers at the bass end are larger and heavier than the hammers at the treble end. The pianist expects the keys to feel consistent along the length of the keyboard much as we expect each of the steps in a stair case to be of the same depth and height.
Stanwood
Now a Pianist has the task not only to walk up and down the staircase but they have to dance up and down their stair case and do it artistically and do all these fancy things.
narration
The action for each of a pianos 88 keys acts in a series of movements much like a catapult, where the press of a key begins a rapid series of increasingly magnified movements through the key stick, the repetition or whippen, and the shank eventually catapulting the felt tipped hammer into the string. Engineers refer to this set of connected mechanisms as a folded beam.
Stanwood
Now here we have the analogy of the piano action which pivots, the main pivot is on the balance of the key, the finger goes down a little bit and the hammer goes up a lot. We have the same analogy the same pivot point, this goes down a little and that goes up a lot.
narration
Using one gram blocks to illustrate the balance beam analogy Mr Stanwood first weighs the hammer and shank mechanism a measurement called the strike weight.
Stanwood
..and ten grams out on the end, this would be the measurement of the weight of the hammer, and the way we would measure this in the piano would be taking the part off and actually tipping it and there we have ten point two grams(10.2).
narration
The process of weighing each component of each of the 88 key mechanisms continues with the whippen also known as the repetition.
It is followed by the key stick which is weighed by balancing it at it’s pivot point. This measurement is called the front weight.
Stanwood
We’ve measured the strike weight and that’s the weight out here – o k. We’ve measured the whippen radius weight. We’ve measured how far it is by measuring the ratio, playing the ten gram weight and seeing how it translates. We’ve measured the front weight by tipping the key on the scale, that would be this weight, o k. We’ve measured the balance weight by measuring up weight and down weight and averaging it by mid-point, that would be this weight.
We have an equation here that has one two three four five six variables. We’ve measured everything except one and thats how far out and thats the ratio.
narration
Mr Stanwood’s equation of balance is written as
balance weight + front weight = whippin weight x the key ratio + the strike weight x the strike ratio.
For the key mechanism measured here the formula would be
38 grams + 27.1 grams = 18 grams x .5 + 10.2 grams x 5.5
The primary use of the equation of balance is to fine tune and perfect the front weight, the variable that makes the key invisible to the player.
All of the data collected in the weighing of each of the 88 keys is then entered into the computer. The data is then analyzed to determine whether individual components should be made lighter by trimming or made heavier
by having weights strategically placed to achieve balance.
Stanwood
Now we’re gonna look at the Jordan Hall Piano, (at the computer) This is a Hamburg Steinway D
It’s a Jordan Hall, and this is the weight of the strike weight as from the factory (looking at the computer) and you can see that there’s a big bump, it gets very low here,
This is the ratio that we calculated using the equation of balance.
The next major component is the lead weight, that’s what you have to throw when you play the key and that can be measured by measuring the front weight where you tipped the key on the scale, erst the measurement of the front weight.
We added what’s called a whippen support spring so we use a combination of the lead weight and the spring and you can see that the effect is that we can use much less lead. So now we have a keyboard where the inertial weights (the stepped weights) are very uniform from step to step, no surprises.
The ultimate goal in the piano action is to really make the mechanism disappear, and have the hammers in your fingers – I mean that would be the ultimate goal, just not even think about the fact that there’s five thousand parts in between you and your performance.
You can just feel like you are right to it.
Connected to the hammer, that’s what we’re after here.
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