Mechanics

DanielePiano wrote:

...in lesson 3 on friction, downweight and return weight of the key were discussed....sorry maybe it's a stupid question but....how do I measure this weight in my piano??...and what is the difference between the action of a grand piano and an upright apart from the size of the strings and the resulting better sound quality (as far as I know)??....thanks 1000

Hi Daniele,

Downweight is the weight required to make the key fall from its initial position (at rest) to its final position, i.e., its end of travel. This weight in grand pianos ranges from about 47 to 58 grams depending on the quality of the action and obviously provided that the action is not damaged, aged, or never regulated. Return weight, on the other hand, is the weight the key exerts on the pianist's finger when it must return from its final position to the resting position. The return weight is lower than the downweight due to reasons primarily related to gravity. In the descent, in fact, the pianist exerts a force that must overcome the static friction of the action and all its internal parts explained by Pianoexpert and the weight force; in the key's return phase, however, gravity helps and some parts, such as the escapement lever, are positioned so that they do not cause friction during their return to position. Therefore, the hammer weight, the weight of the capstan (that set of levers in a triangular shape), etc., help the key return to position. To measure the downweight, you must place lead weights of known weight on the key in its resting position, increasing them until the key descends on its own. You proceed gram by gram. As soon as you add the gram that causes the key to depress, that is the downweight of your keyboard; so imagine that the more weight it takes to depress the key, the harder the pianist will feel the keyboard, whereas obviously less weight equates to a softer and more manageable keyboard. To verify that your keyboard is homogeneous, every key must be weighed and the weights must be placed at the same height for all keys. Usually, a few grams of error are allowed, I think an error of about 2 grams, but Pianoexpert should answer you to know the exact figure.

For the return weight, instead, you proceed in reverse. You press the key whose return weight you want to measure and put a significant weight on it right from the start because this time we will be scaling down. We scale gram by gram until the key returns to its final position. The total weight present on the key at the moment of rising is equivalent to the return weight.

Regarding the differences between upright and grand pianos, there are many; some of these have already been mentioned by Pianoexpert in his video tutorials, but he did not elaborate because we also need to make tutorials on upright action, so he will explain the differences in more detail when we talk about the upright.

In summary, here are the differences:

String length: Greater in grand pianos -> This determines a tapering of the strings in grands, therefore fewer harmonic errors and thus more clarity, roundness, and fullness of sound.

Soundboard: Much larger and more structured in grands -> The soundboard in grands is designed so that sound is propagated across the entire area of the board, and being larger, we find greater amplification and concentration of sound.

Transmission action: The horizontal positioning of the strings makes the grand's action less complex than the upright's because it is gravity itself that performs an important job in the grand, avoiding additional mechanical components for returning it to the resting position. Less complex action means less friction, a more responsive and "faster" keyboard compared to the upright.

We are still waiting for a response from Pianoexpert to your questions, who will certainly be able to deepen the answer.

Hi Daniele,

Here I am to answer you. I apologize for the delay.

The answer that Simone anticipated to you is excellent. I would like to add some clarifications.

First of all, you should have some special small weights used specifically for this purpose. The weight is placed on the front edge of the key. You must keep the damper mechanism lifted so that it is not "counted" in the measurement. The key must descend slowly UP TO THE ESCAPEMENT POINT.

The differences between the upright and the grand are numerous. A video tutorial on the subject will be released. The grand is preferable from a mechanical point of view. Its "repetition" is easier and faster (provided it has been well regulated).

I have some observations regarding overall quality. You know, sometimes we prefer to drink an excellent sparkling wine instead of a bad champagne, and this fits well with the difference in quality between the two instruments. Some small grands have terrible sound performance. Some high-end brand uprights sound like "Paradise." One must also take into account "commerciality" and... the wallet!!!!! In short, what determines the overall quality of a piano is: the refinement of the design (bracing, soundboard, position of the capstan, position of the bridges and their respective material quality), the scale (the highest or longest will have greater performance), the quality of the hammer rail, and the entire transmission mechanism. In the refinement of the design, as indicated by Simone and as already mentioned in my videos, the proportion between the downward weight and the return weight is very important. Good music. Paolo