So, maybe your piano sounds like it's in tune, but perhaps you don't like the tone. Maybe all of the keys play, but they feel heavy under your fingers. There are many aspects of the piano playing experience, but maybe the three most important are what I like to think of as "tune, tone, & touch." They're like the three legs of stool. If any one isn't solid, then the whole thing is wobbly. Let's take a peek at each of these three aspects of the piano experience.
We usually like to start with a tuning. When pianos are out of tune, our brains often get preoccupied with the imperfections, and the other aspects - tone and touch - are perhaps a bit less noticed. Tuning involves a number of different considerations: Are we tuning the piano to a specific pitch? The "standard" pitch in general in the United States is called "A 440," which refers to the A above middle C on the piano. When that note vibrates at 440 cycles per second - called 440 Hertz - it's at the "standard." Many orchestras tune to 440,
while others tune to 441 or 442. Piano technicians at the Juilliard School, in New York City, maintain their fleet of pianos at 440.5, because one nearby famous concert hall tunes to 440, while another nearby hall tunes to 441.
Another very important aspect of tuning is to work on unisons. On most of a piano's 88 notes, the hammer strikes three separate strings. On some other notes, there are two strings per note. Only the low bass notes have one string per note. So, when I'm tuning middle C, for example, I need to separately tune three different strings. My goal is to get those three strings to be as close as possible to the exact same pitch. We refer to those three strings as a "unison," because we're trying to get them to play well together with each other.
Once we get the piano in tune, our brains start to focus on other aspects of the piano. For example, what is the quality of the sound that the piano produces? Is it smooth, sweet, and mellow? Bright, strong, incisive? Does the nature of the piano tone differ when we play quietly compared to when we're going for fortissimo? Do we like the tone? Does the tone annoy?
We're able to adjust the tone of the piano in a number of ways. One way is to work of one or more of many adjustments to the piano's "action" - the mechanical devices that connect the keys you play to the hammers that strike the strings. Adjusting the action can have a major effect on the tone of the piano. And adjusting the action also affects the touch, which is the third leg of our stool.
We also adjust the piano's tone by making small adjustments to the strings. On the unisons I discussed above, if the hammer doesn't strike the three strings of the unison at precisely the same moment, the tone will suffer. We can level the strings - make very small adjustments to the string height - so that the hammer will strike all three strings simultaneously.
Another way we can affect tone is to work on the hammers. Piano hammers are made of a wood core surrounded by layers of high-quality wool felt, attached to the wood core under tension. New piano hammers have a beautiful rounded shape at the strike point - the spot where the hammer strikes the strings. New hammers are also quite springy. There's a good bit of elasticity in the wool felt. When the perfectly rounded hammer strikes the string, there's some bounce and flex.
If you feel that your piano's sound is too mellow, then the hammers might be on the softer side. We can add special liquids with hardeners to the hammers so that they get a bit stiffer, to produce a brighter tone.
On the other hand, if you feel that your piano's tone is too harsh, bright, or brittle, then we can work to soften the hammers and get them a bit more springy. Over time, hammers get stiffer and denser. They get compacted from the thousands of collisions with the piano's steel strings. You'll notice that older hammers usually also have grooves from the strings. The grooves can tend to make the hammers a bit flat on the top. Instead of a rounded crown that strikes the strings at a precise point, the grooved hammers strike the strings over a larger flattened surface. That larger strike surface, combined with the dense and compacted wool felt from use over time, tends to create a tone that might be considered very bright, or perhaps harsh. We can make the piano's tone more mellow by sanding the hammers to return them to their original rounded shape, and we can make many small pokes into the wool felt with needles, to loosen up the wool felt and introduce some bounce and elasticity again.
The third leg of the stool is touch. How do the keys feel under your fingers? Do they feel heavy? Light? Just right? Are you able to play pianissimo on your piano, or do you feel like you need to strike the key with a certain amount of force, and if you use less force, you don't get any sound at all? At the other end of the dynamic spectrum, are you able to play as loudly as you would like? Do you feel like you have control over the piano? Do you like the way the pedals work? Do the dampers lift evenly? Do they lift too high?
A modern piano has more than 10,000 parts.
number of adjustments
to some of those parts: the keys, dampers, hammers, wippens - which work together to get the hammer to move in just the right way to strike the strings, which then get silenced by the dampers exactly when we want. These many adjustments are referred to as "regulation," and they have a great effect on the touch of the piano, as well as the tone.
So, there you have it. Tune, tone, and touch. The three most essential aspects of a satisfying piano experience.