Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Piano hammer voicing techniques.

I am having a small dinner meeting/seminar here tonight with a couple of colleagues.

One of them attended a conference, last year I believe, where Jack Brandt demonstrated a particular problem with the way the felt is manipulated over the molding in some Chinese hammer making.

I have asked my colleague to bring the felt samples along so that I can take some photos of the problem Chinese hammer makers are having.

Apparently with the Chinese felt, it does not stretch smoothly on the inside of the curve over the molding. It bunches up like an accordion or squeezebox.

So the result is that sometimes when you jab the hammer with the voicing tool you are ending up in an air pocket........ doing a whole lot of nothing.....

From what I understand, the Chinese are after Brandt to reveal his process to them.

Knowing how the Chinese do things, I predict in a couple of years they will be making some of the best hammers in the world. I'll also say Steinway will out source their hammers.

I still haven't got the confidence to try something like this on a customer's hammers, but I can tell you what I did. I had a brand new Yamaha V-124 with extremely hard hammers, producing a lot of upper partials -> harsh and nasal tone.

This was before my piano tech days, some 5 years ago. I tried to side needle, but with little result. A lot of work though, because getting the through the hammers with a needle was no easy task.

Then I heard about fabric softener and acetone, and logically it made sense. This i used, once, and it opened up the hammers really nicely. After that, good side needling could be done, getting me a pretty good end result.

As I learn about all techniques, subjective preferences and no-no, I realize I would never have pulled that one off if I knew more. Not because of the technique itself, but because I would be scared to death to use it.

BDB said something in a thread half a year ago, about learning voicing as an ongoing process through piano tech life, including ruining a few sets of hammers. I found this comforting

Much about voicing are poster's highly subjective opinions. There is a catch 22 - to succeed in voicing piano hammers you have to be really good at it (practice it) in order not to ruin the hammers. Then, to practice it, you would have to be prepared to ruin hammers.

Trying out all different kinds of suggestions on a set of "disposable" hammers is my way to go, and I'm getting better at it. Lastly, i try to stay imaginative and use common sense. It hasn't gotten me into any major trouble yet

Great post Patrick!

As one of my mentors said to me: Every tuning should include some sort of voicing - even if it is just one hammer.

I have had different phases in my voicing career - back in the late 90's I think I used to overdo it. I'm sure I left some pianos to mushy. I went through my steaming phase and I still think that steaming has its place (even though I haven't used it in quite some time.)

The main thing is try! There are no shortage of old neglected pianos out there! One thing that has really helped me was that years ago I got really fast at reshaping hammers. I frequently do quick reshapings as part of normal piano service.

Another thing is to always have a project piano (or two, or three...) to work on. It gives you complete freedom to do whatever you want to the hammers. Steam them into mush, and then lacquer them back up, then soak 'em with acetone, then file 'em again. See what happens! Learn what the limits are.

There is a certain amount of risk involved with this type of work. The pay-offs are worth it.

For some years I have been presenting classes and seminars on such esoteric topics as “How the Piano Works,” “Understanding the Modern Piano, “Voicing the Soundboard,” or “Voicing the Whole Piano.” The importance of these classes and seminars is generally underestimated. After all, if one is not planning on designing and building new pianos why should it be necessary to know anything about stringing scales or soundboard design? Still, I continue to advocate these classes—and present them at considerable personal expense—because it has long been my belief that the more we know about the instrument we work on the better our work will be and the less damage we will inflict on the poor things. The less mysterious the piano becomes the less fear we will have in trying something new and the more confidence we can have in trying something a bit out of the norm. Not to mention the fact that fewer mistakes based on ignorance will be made.

Understanding the acoustical differences between different types of scales might well keep one from attempting to achieve impossible results and, in the process, causing irreparable damage to the hammers. Understanding the physics of what is happening at the bass/tenor transition might prevent one from over-voicing—and ruining—the hammers in that area when it is really the soundboard system that needs voicing. Indeed, it will open up whole a whole new area of voicing potential techniques; techniques that do not include the hammers at all. Understanding what is really causing that sharp, percussive attack and abnormally short sustain time might prevent destructive and useless hammer voicing techniques and enable one to properly explain to the piano owner what is really making the piano sound that way. And the list goes on….

To use the present case as an example, you do not really need to know that, “Cationic softeners bind by electrostatic attraction to the negatively charged groups on the surface of the fibers and neutralize their charge; the long aliphatic chains are then oriented towards the outside of the fiber, imparting lubricity.” But it is helpful to understand that, quite simply, fabric softeners work by lubricating the felted wool fibers. And thinking about this for a time will be helpful in understanding what effect this might have on the hammer as it impacts the taut strings in a piano.

The more one knows about wool, felt (including the felting process), hammer making and the interaction between the hammers impact against the strings the less mysterious hammer voicing becomes. The idea of treating hammers with fabric softener then becomes a relatively simple decision about whether or not lubricating the surfaces of interlocked and stressed wool fibers in these specific hammers will be beneficial or destructive to the production of piano tone in this particular piano.

I am obviously in favor of experimentation—I certainly do enough of it myself—but as much as possible I try to make this informed experimentation. Otherwise it becomes something like the Edison principle of invention: try everything you can think of and eventually something might work. With luck you might end up with something that works but you’ll have wasted a lot of time and ruined a lot of hammers in the process. And you’ll have learned very little. Having a working knowledge of the materials from which the piano is made—wood, steel and iron, wool, etc.—will give a significant head start in subsequent experimentation. As well, understanding how strings of different physical characteristics vibrate will help one to analyze the sounds heard and will make for much more intelligent voicing choices.

ddf

There are lots of things that can give you insight. The other day, I was playing bocce, and someone asked my about my balls, picked one up and dropped on the court. Then he dropped one of his own. (These are metal balls, for volo, not plastic balls.) Mine bounced about 6 inches, while his barely bounced at all. I knew the difference. Do any of you? Do you know how it is related to voicing?

Del,

I agree on the need of knowledge. Still, I wouldn't encourage anybody to wait until they know it all before doing empirical research, because chances are you will never get there.

It is very easily related to the music field. Insufficient theory skills should never stop you from playing, writing and making music while you work on your theoretical deficiencies.

Is any of this material available from you?

Thanks for the explanation of how fabric softener works!

Kees

BDB: different weight of the balls? Different ground composition? Enlighten us!

Was one of the balls made by Ari Isaac and the other from China?

It will be Real Soon Now. We're still trying to figure out the best way.

ddf

I don’t think I have ever encouraged anyone to wait until they know it all before doing “empirical research.” In my case I would not yet be qualified to do research of any kind! I do, however, encourage those wanting to expand their knowledge and skills—and that should include everyone wishing to make piano tuning and servicing a profession (even a part time profession)—to first do the requisite background study to guide them along the way.

Generally speaking, empirical research is used to answer questions or to test a theory. To continue using the idea of treating hammers with fabric softener it might be a good idea to learn just what fabric softener is formulated to accomplish and how the chemicals affect wool fibers in an effort to understand what might happen when it is applied to hammers. This knowledge will be quite useful in predicting how the fabric softener might work when applied to hammers of varying physical qualities and what might be the acoustical effect.

I continue to believe it is a good idea to acquire as much background information as possible before moving to the empirical research phase. Too often, I think, the question is there and the application is there—all too often on an unsuspecting customer’s piano—but the theory is missing.

ddf

As far as I know, the Chinese only make plastic balls. The brass balls are all Italian. Externally, they are pretty much the same. The weight falls in the same range, but his balls are designed so that they do not bounce.

What you might want to consider is how hammers with the same characteristics might affect the sound.

I could imagine some kind of energy-absorbing layer under the surface. I don't know how bocce balls are made usually, but if you imagine a golf ball with sand inside instead of rubber bands, that would do it.

Otherwise, different tension on the surface could also make a difference, but I can't think of how that would figure in a metal ball.

What the former alternative would suggest is that the energy absorption characteristics of, e.g., the underfelt layer on a piano hammer would affect the bounciness of the hammer, which in turn affects how long the hammer contacts the string, and thereby the tone (and even how long the felt will last).

Del, Keith, and all,

When reading Del's post # 1517663, specifically the part about voicing other parts than just the hammers, this put me in mind of earlier posts, where I read about adding mass to bridges, e.g. by drilling holes and filling them with lead, or even Keith's suggestion of inserting an old engine valve spring between a back post and the bridge area of the soundboard:

http://www.pianoworld.com/forum/ubbthreads.php/topics/1461809/kpembrook.html#Post1461809

I had asked in that thread what sort of forces would be typical in this example: just a slight force (i.e. having to cut the spring almost down to size), or several pounds (i.e. having to compress the spring before installing it). Perhaps one of you could elaborate, either here or (more appropriately perhaps) in the other thread?

Good idea, Del, but the sources of such information are pretty limited and often not trustworthy. Thank you for being a trustworthy resource!

So, do you see any particular drawbacks on using fabric softener/alcohol solutions for hammers that have hardened due to age?

Could you share any thoughts you may have about lanolin in wool? I plan on trying an alcohol/lanolin solution on my next project piano.

Well, they are not all that limited. The Piano Technicians Guild has long been a source for (mostly) reliable and appropriate information. To be sure, it does take some effort and, occasionally, some expense, to track it down but it’s there. These resources include local chapter meetings, regional seminars and annual conventions. Not to mention The Piano Technicians Journal. During the 38 some odd years I have been a member I’ve attended hundreds of these events. Often I’m there as an instructor/lecturer but more often I’m there as a student simply wanting to learn more about some part of my craft from someone who has taken the time and effort to study a component or process long enough and carefully enough to have gained knowledge and skills worthy of being shared.




The only drawbacks I see is when technicians use the stuff without understanding what it is that they are doing.

Fabric softener works by coating the wool fibers with chemicals that act as lubricants. Lanolin is a wax and, when thinned out sufficiently, will probably accomplish essentially the same thing. The effect on the hammer, I should think, would be to make it some “softer” and reduce its resiliency. If my speculations are at all accurate this would mean that hammers so treated would stay in contact with the strings longer; damping out more of the energy in the higher partials in the process.

Keep in mind that when techniques like this are contemplated it because there is something wrong. The hammers are too hard or too dense—often coupled with being too massive—for a particular scale and soundboard combination. These measures are being considered as being less bad than other available—perhaps more traditional—alternatives.

Please keep in mind that I am speculating here as I have not personally worked with either product as a hammer voicing tool. In my own work I prefer to match the physical characteristics of the hammers to those of the piano I am working on. It never ceases to amaze me that technicians—no one on this list, I’m sure!—continue to fit hammers to pianos that are completely inappropriate to the scaling of the piano. And then wonder what heroic voicing techniques can be used to make the sound of the combination acceptable. And, after hours of exhausting work and the hammers have been thoroughly mutilated beyond any recognition, with the sound at least somewhere close to acceptable declare them to be “good” hammers. And buy more for another inappropriate matching.

ddf

Thanks, Del.

Actually, I (and others) have already written on both of these subjects both on this list and on Piano Forum.

The valve spring idea is one many of us experimented with back in the 1960s and 1970s. It has been pretty much discarded now in favor of auxiliary ribs of appropriate length and cross-section used in appropriate locations. A fairly complete discussion of this concept can be found in an article written by my brother, Darrell, and published in—where else?— The Piano Technicians Journal a couple of years back.

I think I originated the idea of inserting lead weights into certain areas of certain types of bridges. While I’ve not written about this technique in the Journal I have presented the basics in various posts on these Piano World Forums.

Both techniques have also been the subjects of various classes presented at PTG events around the U.S., Canada and Australia. Alas, I don’t know if they have made it to South Africa as yet. But the Journal is available world-wide.

ddf