My piano technician says that my piano needs voicing. What does she mean?
Good question. First off, never be afraid to ask your technician what something is if you don't understand. We piano techs, like many other people who work in a specific industry for a long time, sometimes fall into the trap of using too much lingo. I will try to explain "voicing" a bit for you.
Voicing is the process of changing the quality of the tone that the piano produces. Voicing is an important step in piano care and maintenance, and one that is often overlooked. Many piano players incorrectly assume how a piano sounds now is just the way it is. This couldn't be farther from the truth. It is not the same thing as tuning, which is adjusting the pitch. Pitch refers only to the frequency with which a string vibrates and is completely empirical. It's essentially a math issue. A note is either in tune or it's not. A440 is a pitch which means that the string is vibrating at 440 Hz or cycles per second. On a piano, A440 is the A directly above middle C. If that note is not vibrating at 440Hz, it is out of tune. A lower number means it is flat, while a higher number means it is sharp.
Voicing, however, is not so cut and dry. It deals with the subjective qualities that are much more difficult to measure and define as right or wrong. A good example of what this means is the human voice. What if we asked Bob Seger and Whitney Houston to sing the same note? Could you tell them apart? Of course, we all could. The difference is in the tonal qualities of their voices, not the pitch. This is what is altered when a piano is voiced.
The basic techniques of voicing a piano are simple. You can't realistically change many things about your piano such as the soundboard or the strings. But you can change the tone that is produced when the hammer hits the string. That's where it all happens. Technicians alter the tone by changing the firmness of the hammer. If a piano is too bright or harsh or loud or abrasive in its tonal characteristics, a technician can "soften" the hammer by taking a tool that holds needles and sticking it into the hammer felt at specific locations to loosen up the felt fibers. This will soften the tone. If a piano is too dull or muffled or lifeless or soft, a technician can use various techniques to build more tone. Among these would be filing or reshaping the hammers with sandpaper or lacquering the hammers. Filing will generally provide more subtle changes when that is the goal, while lacquering can show much larger changes. Clear, water white lacquer is mixed with thinner and applied to the felt of the hammers. When the thinner evaporates away, the solid components of the lacquer remain, increasing the density of the felt and stiffening the fibers. This will produce a stronger, brighter tone.
How do you know if your piano needs voicing? Instead of answering that directly, let me rephrase the question. Do you like the way your piano sounds? If your answer is yes, then you don't need voicing. There is no one "right" sound. What might sound perfect to one person is awful to the next. That's OK. I might not like the same flavor of ice cream as you either. Voicing and tone are just that, a matter of taste. On the other hand, if you currently hate the sound of your piano, you certainly should give voicing it a try. Most concert pianists are relatively happy with the voicing if it is consistent from top to bottom. It might be softer or brighter than their ideal, but if it's consistent, they can adapt a little bit and play just fine. If there is no consistency, they will be very unhappy.
Before a piano can be voiced, it must be in excellent tune and regulation. Once those two requirements are met, you and the technician can hear what the piano truly sounds like. Also, keep in mind that voicing is one of the finer arts in the world of piano maintenance and care and should only be performed by an expert, experienced technician. It is best to seek out the top technician in your community for this particular task. They may charge a little more than others, but the results will be worth the extra money. One option is to take your piano technician to a local piano store and find a piano that you really like the sound of. He or she may not be able to guarantee that they can make yours sound exactly like it, but it gives them a good idea of what you like.
I have learned some of my own voicing lessons the hard way. Early on in my life as a piano store owner, I couldn't resist the temptation to voice pianos that didn't suit my taste. I would run across one that I personally didn't like because it was too bright and harsh for my taste. After spending hours softening and congratulating myself for a job well done, the next person I showed the piano to would inevitably say, "well, it's pretty nice overall, but I wish it were a little brighter". Eventually I learned to leave well enough alone. If I'm not the one who will be buying the piano, I am not the one who should make the voicing decisions. After all, beauty truly is in the ear of the beholder.