I've read differing opinions, so curious what the consensus opinion is here, or what others think - both from players as well as piano techs.
The Knabe upright (47", 2009) piano I am strongly considering for many reasons feels a teensy *drop* too firm in the action. Nothing major, but a) my son (7 yrs old) and I are coming from playing on a very good Yamaha YDP-223 (digital, btu graded) where the touch was obviously much lighter. and b) the Knabe feels a *little* bit firmer than some other verticals I have tried. It's not really a deal breaker for me, but I'm wondering if a piano tech (I am in NYC) can make a minor adjustment just to lighten the touch by a 'hair'. Make sense?
I have read and heard from others that on vertical pianos, there is not much that can be done "in a big way on touch -- and I totally understand that. But I also get the impression that minor improvements (in either direction) are possible.
Of course, this piano has received zero playing time so it has not "broken in" and I imagine that might lighten up the touch over time anyway, but I'd like to lighten it a *drop, drop* at the get-go.
There are several parts to the “touch,” or “touchweight,” equation. The way technicians measure “touchweight” is really an indication of an action’s static touchweight
only. In other words, how everything feels in very slow motion. It is useful, when combined with a similar measure of “upweight,” for learning how much friction is present in a given action. But it tells us little about the dynamic response of the action.
In the upright piano downweight is a measure of how much force is required (1) overcome friction, (2) to rotate the keys on their pivot points (and front portion of upright keys is generally a little heavier than the back portion unless they are back-weighted
), (3) raise the weight of the wippen, (4) rotate the hammerbutt, hammershank and hammer (initially there is a little “weight” involved here, but not much) and (5) bend the hammer return spring. In terms of static touchweight (in a vertical piano action) the biggest contributors to the static touchweight measure are the weight of the wippen assembly and the tension of the hammer return spring.
In most vertical pianos the keys are relatively light—and, as mentioned, the keys are usually a little front-heavy so they actually work to decrease the static downweight measure—as are most vertical piano action wippens. Depending on the actual geometry of the specific action the hammerbutt assembly usually doesn’t add a lot of weight to the static downweight measure. The hammer return spring will, however, and this can sometimes be significant. (As would the damper spring if the damper pedal was not always fully depressed during this measure.)
Dynamic touchweight is a whole other issue. This is a measure of how the action feels when it is played with enough keyforce to move the hammers rapidly toward the strings. Now both spring force—that hammer return spring—and the mass of all of the parts, especially the hammer, come into play. The more massive the action parts, the higher the dynamic downweight will be. This won’t affect how the piano feels when played slowly at pianissimo
levels but it can have a significant effect on how it feels when played rapidly at forte
levels. Unfortunately piano technicians do not have any readily available tools with which to measure and quantify dynamic touchweight; it is a very subjective measure and is determined largely by how the action “feels” to the individual pianist.
What you are finding in switching from a digital to a piano is that there is a difference between a mostly spring-loaded, relatively low-mass/low-inertia key system and a spring-loaded, high-mass/high-inertia system. There is probably some difference in the amount of spring force used in the two actions but generally there is a much bigger difference in the overall rotating mass—hence, inertia—between the two systems.
Because dynamic touchweight is not quantified by actual measurement there is a lot of subjectivity in the answers given in response to your question. One person’s “firm” action will be another’s “light” action and yet another’s “heavy” action.
Most vertical pianos have actions that are generally considered “light” by teachers and accomplished pianists. Usually when teachers complain that their students are practicing on piano with to light a touchweight the piano involved is a vertical of some kind. Sometimes—as I believe is the case with Knabe verticals—the touchweight of the vertical action is increased somewhat by back-leading (installing one or more lead weights somewhere toward the back of the key). Generally this is a good thing because front-heavy keys can contribute to chronic repetition problems as they are more sensitive to even slightly high amounts of friction.
It is unlikely that the touchweight of a modern vertical piano action such as that found in the Knabe you are considering will be excessively heavy even though it may feel that way to you at first. Excessively heavy actions are usually found in grand pianos fitted with heavier-than-necessary hammers and (sometimes) with inappropriate overall action lever ratios. In the case of the Knabe piano you are considering, if the action’s dynamic touchweight really is too heavy— assuming it is not plagued by excessive friction—it would probably be due to the hammer return springs being too strong and these can be adjusted by a competent technician if necessary.
Unless the action in the Knabe is actually diagnosed as being “heavy” by a technician familiar with how good piano actions function and feel I’d assume that it is functioning properly and within normal limits. Assuming you go ahead with this purchase I’d suggest that you (and your son) play the piano for a few months and then re-evaluate the situation. If, after this acclamation period, you still find the touch to be excessively firm—in your opinion—then have a discussion with your piano technician about your options. Again, assuming the friction points in the action are within reasonable tolerances, I’d then be looking at the tension of the two springs involved: the hammer return springs and the damper springs. (The damper return springs come into the picture when the key has reached about one-third of its stroke and, if they are too strong—a fairly common problem with modern piano makers—this can make controlling the action at pianissimo