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Wire gains mass proportional to the cross-sectional area. Wire gains breaking strength proportional to the cross-sectional area. It is as simple as that.

All piano wire breaks at the same pitch. This means that as the diameter increases and the tension increases the break point stays the same in relation to pitch.

The above truism does diverge slightly as you go to the smaller gages common to piano scales.

Ok, thanks. So is it your contention that people rescaling pianos are wasting their time, or that it does work, but the parameters they are working with to explain it are invalid?

Rescaling works. I rescale to minimize changes in tension. The result is more uniform volume and more stable tuning. It just has nothing to do with the percentage of breaking strength. The universality of computers makes the calculations easier than they would have when old piano scales were developed, so this is one of the few things where it is possible to improve on the original, at least sometimes. Some scales are so out of whack that they cannot be improved much.

It may be possible that other materials can make for improved scales, but experimenting with materials requires that different wire is made from different metals, and that is beyond the capability of most people.

BDB, Stephen Paulello has been making his own piano wire for about 20 years, and Pure Sound Piano wire has been around for quite a while also. The work of which you speak in your last post #2508463 has been done by these people.

From Paulello's website, some pertinent information:

"The 5 types of STEPHEN PAULELLO wires result from two different aspects of their manufacturing:
choosing raw material according to its composition
perfecting methods of wire drawing which modify several mechanical or chemical parameters: speed through the dies, rate of metal deformation, temperature, lubricant …
This results in 5 degrees of mechanical performance, from highly traction resistant steel (Type XM), to almost pure, less resistant iron, resembling early XIXth century stringings (Type 2).
Breaking loads extend from 3000 N/mm2 (type XM’s small diameters) to 1000 N/mm2 (type 2’s large diameters) modern stringings"

Some tables, based on laboratory testing of the 5 types of wire. Here's the link: http://www.stephenpaulello.com/site...tics_of_the_5_types_of_paulello_wire.pdf

You have said, "Most of what people say about piano sound and the relation to physics and math is not well grounded."

It seems that Mr. Paulello is offering evidence to the contrary of your assertion. On what would you base your belief that these types of wires are not based on good science and statistical evidence? Where is your evidence to the contrary? An opinion with no basis in fact or direct experience has no standing.

The last I knew, you have never even listened to pianos using these wires, yet you dismiss the conclusions of a number of end users who have used these materials continuously over a period of years. Their ears tell them something far different than what you believe. I have never experienced anything other than delight from my customers whose pianos have been restrung with Paulello wire.

My long experience rescaling pianos using breaking percentage as the foremost criteria has convinced me that working towards the the most even progression of breaking percentages possible throughout the scale by combining wire types of varying breaking percentages will yield the most even, balanced and blended scale. No other means of scaling will have as satisfying results.

Mr. Paulello's reputation does not attest to his abilities in physics or math. Physics and math may make reputations, but reputations do not make physics or math.

In order to change the breaking percentage of a string, he would have to change the material of the string. That can affect other characteristics of the string, which can change how it sounds. (I once asked you to do a simple experiment that could have shed some light on at least one of those characteristics, and you refused.) What I have shown only proves that the explanation is not correct, not that there may be other results that may make his strings sound different.

I have listened to the recordings of Mr. Paulello's pianos that you posted. I was not impressed. That could be a matter of taste, but when you said that the piano might not have been voiced properly, you were denying one of the properties that I said I was aiming for, which is a minimum of voicing.

I made no mention of Stephen's reputation. I thought it pertinent to mention him, as one of the two string makers of piano wire of varying breaking percentages.

Stephen's quoted comments allude to some differences in material. One of them would be the amount of carbon in the steel. There may be others, but Stephen has never really said, and likely considers the details of the exact composition and manufacturing processes to be proprietary. That's reasonable, it's a concept known as intellectual property. He likely is doing some things differently that indeed do make his strings sound different which, for me as an end user, is the whole point. And they do sound different. But you've never listened to them, so how would you know?

If you had looked at the chart of Practical Breaking Load values, you would see that the laboratory testing (likely done by an independent testing facility, as Paulello's firm is quite small) yields PBL values for each of the 5 wire types that are different. That is listed for each gauge and wire diameter that he makes. If you dispute his results, then explain how and where they are wrong.

You have not proven that the explanation is not correct, only stated that. What have you shown?

Let's be careful with language. I offered links to recordings of two of Paulello's models. He has been making the SP 287 for some time, and that instrument can stand on its own as a fully realized design. I have heard a recent CD on a studio reference monitor system, which will minimize coloration. I think it is a superb instrument. The other instrument of which I spoke was the Opus 102, which is a prototype that is nearing completion and the final voicing is not yet complete.

I'm not denying anything, BDB. It's not my piano, and I don't decide how and when it is voiced. Stephen Paulello the designer and builder does. He told me it is not fully completed but he knows nothing of you and your all important unsubstantiated opinions.

It's not my job to do experiments for you. If you had real interest, you would do them yourself. That's known as intellectual curiosity.

And it is not my job to prove anything to you. Other people understand what I have said.

I've been meaning to write something on the relationship between momentum and touch in the piano action.

Early Pianos had light hammers, as pointed-out. Pape and Pleyel Pianos went out of their way to lighten the hammers as much as possible, even by making them hollow, like Cristofori did.

There are two elements that make up momentum and the energy that makes the string vibrate on impact: the mass of the hammer and the velocity of the hammer.

If the hammer is very heavy, it does not need to acquire so much velocity because the energy stored-up in the hammer is transferred within a slower swing of the hammer. So the key need not be played with much velocity to get a strong sound. This kind of action is quite adept for 'weight playing'

If, on the other hand, the hammer is very light, to get the same amount of volume, while keeping the sound full (by not making the hammers hard) you necessarily need more velocity to get the same strength of tone. Erard Pianos in the Late 1800's also had more Hammer-Swing to get volume with less weight. This kind of setup does not respond well to 'weight playing' because weight playing does not produce sufficient velocity. The ideal technique would tend to shift more towards velocity-playing or 'finger action' which uses nervous muscular energy to propel the hammer at a faster rate, if the pianist has developed his muscles through articulation and finger excercises etc.

The heavier hammers will have a more percussive sound, more of a 'thud' when playing, the lighter ones more of a singing-tone but if the hammers are soft (in order to get lower partials to sound louder, therefore a full sound) the action will need an articulated touch.

My experience is that many pianists have a hard time with articulation and feel more secure with an action which emphasises mass over velocity..

I am reminded of something that the Pianist Michelangeli said to a friend. He said that when piano actions became too heavy he had to eliminate all repertoire that had glissandi in it because it became impossible to achieve what he wanted.


I think that the emphasis on Mass over Velocity has really changed the way the piano is played, taught and conceived

Thank you for your interesting reply.

It confirms what I experience on my piano since hammer mass was reduced. Even though I use arm weight when required, I naturally play with finger articulation most of the time as I personally can achieve more precision this way (YMMV).

The hammer weight reduction enables me to be more connected with the instrument and it also improved (an already good) sustain on the piano.

Bosendorff and acortot I couldn't agree more. I have been making high leverage/low inertia actions since the early 1980's and the control, response, projection, durability, and musicality can not be equalled any other way.

Thank you all for a very inspiring thread. And thank you Acortot for the link to your blog. I read it with great interest. What is still missing from the discussion is how hammer properties like hardness, density, rebound and mass relate to different string material as available from Paulello or the historical variants of wire (differing length, alloys, diameters etc.) Perhaps someone would like to try?

Have not used Paulello so can't help with that part.
It helps to understand the carding/felting process then the technique for pressing/gluing hammer felt to the wood core. There is hot press and cold press.
Wool fibers have resiliency/springiness which gives them their nonlinear spring properties that really make a big difference when present.. Some processes can compromise this resilience as well as soaking them with lacquer as part of voicing.in my humble opinion hammer mass should be proportional to string mass. It makes no sense to me to try to move a large massive bass string with a small lightweight hammer that was made that way to achieve some action parameter. More Massive hammer brings out fundamental frequencies and enhances tone definition and color much more efficiently because ov it's mass and resilience and I don't buy the F=MA equivalence claim.
Again, heavy don't me excessive.
So really dense cold pressed massive hammers with no lacquer are a really good place to start.
Next you need someone that knows how to voice them properly for what type of wire that are trying to move.
Also it's not just moving the wire. As wire is coupled to bridge and soundboard the design features of these major components play a huge roll too.
If you are getting percussive noise maybe it's a soundboard issue, not a hammer mass issue.

Hi Klavimaniac: I don't know that there is a simple answer to your question, as there are other variables to be considered besides the wire make and type used, such as whether or not a piano is a higher or lower tension scale, new board or original (along with its condition). Add to that our individual tonal preferences and voicing protocols.

I will say that older instruments generally had softer and lighter hammers. Nineteenth century pianos would have lower tension scales on average. The Paulello Type 2, type 1, and type 0 wires are the modern variant that are designed to be used on those instruments, depending on their needs. The type 1 and type O wires are used successfully in areas of the scale on modern pianos where the breaking percentages fall too low for optimal tone, such as the low tenor and often the monochord areas of the bass.

Most of the pianos we are rebuilding are modern instruments that are less than 120 years old. Of course, the restoration of a piano where the rebuilder does not feel compelled to observe the protocols of the original can be a blend of many things. In chasing my own muse, I seek to create instruments that are as balanced and blended as possible, with a consistency of tonal character from note to note. To achieve this, several things stand out as very important. First is the choice of Paulello wire types that address the problem areas of the scale to best arrive at this uniformity. Second is the careful controlling of the weight of the hammers, I control strike weight to a tolerance of .1 gram as the hammers progress up or down the scale, and favor Ronsen low profile Weikert felt hammers that best mimic the hammers of old, and meet weight targets that generally are somewhat lighter than what others might be using. This, along with the use of the Fandrich-Rhodes key weighting system, results in a lower inertia action that is very consistent in its response and tone.

Others may have different ways to get to what they are looking for, and get good results in the process.

There is a lot of buzz that goes on in the piano world, which few people bother to examine with any degree of accuracy. It would be easy to measure old hammers and compare them to new hammers, but I have never heard of anyone doing it. It could be that old hammers were lighter in some parts of the scale and heavier in others, in any case, so one cannot speak in generalities. There were old hammers that had cores so thin in the treble that they would break along the trim line of the felt, and there were old hammers that had massive hammers in the bass.

There is some discussion of hammer design in one of Dolge's book, which is recommended reading. Dolge was a major hammer manufacturer.

The same thing is true of scale tensions. There are old pianos that have very high tension in some areas of the scale, and very low tension in other areas. The math was difficult to do, so many piano scales were laid out according to how nice the bridges looked and tradition, rather than any principles of physics. The sad thing about this is that it actually would have been cheaper to design a scale with the proper physics, as it would mean more notes in the highest register using thinner wire, which is cheaper than thicker wire.

Some of this was discussed in Piano Tone Building, the minutes of a conference of piano builders from about 100 years ago, which is also recommended reading.

BDB, I have tone-regulated/rebuilt about 5,000 grand actions in my career. Is that insufficient evidence to support what I report finding as regards hammer weight?

If numbers of pianos that one worked on were all that counted, the manufacturers would still have you beat.

I don't get your point BDB. I have more experience seeing more different pianos made over a longer period of time than any one only working in a piano factory would ever have in a lifetime.

To Ed's point, BDB, what have you done that "counts"?

Your ad hominem remarks to those with whom you disagree serve only to show your lack of depth and understanding of the material, and a consistent unwillingness to challenge your own beliefs and perhaps actually learn something new. Any time you are shown evidence to the contrary of your stated positions, you gloss over it with snide remarks. When I showed you Paulello's charts related to Practical Breaking Loads, you ignored it, even though I specifically asked for your response to the information given. To me this should be a dialog between colleagues, not a pissing contest.

Alfred Dolge's book and Piano Tone Building are indeed good reading. I have owned both books for 35+ plus years, and they are well worn. I have weighed more old hammers than you ever will and know their variability. Since I rescale every piano that I rebuild these days, I have always taken measurements of the stringing scale so that I will understand what was there to begin with. Some of those scales were all over the map. Having said that, careful reading of my previous post will show that I am not contradicting myself, as I spoke to the general trends and not to specific pianos.

A lot of the old scales were blind copies of other existing pianos. When you read the comments of many of the participants of the conference in Piano Tone Building, it is remarkable how little some of them understood about the pianos they were building. William Braid White was their beacon in the night.

Two other older classics recommended for your edification are "A Treatise on the Art of Pianoforte Construction" by Samuel Wolfenden, and "The Modern Piano" by Lawrence M. Nalder.

I have done the math.



An "ad hominem" argument is when you use the reputation of the person making a claim to show that the claim is right or wrong. That is what you are doing here, by citing other people instead of the mathematics and physics. I have avoided such arguments.

Mr. Paulello's charts only give information about the wire he makes, or has made for him. The only thing that it shows is that it has some characteristics that differ from other piano wire. It does not show any correlation between the breaking strength and changes to the tone of a piano strung with his wire. What use to me is that? On the other hand, I have repeatedly shown why the breaking strength is not likely to be the determining factor in how a piano note sounds. I am still waiting for someone to explain why it should be. All I am getting are ad hominem arguments: This guy is doing something, therefore it must be true.



Having made so many measurements, one would think that you might be willing to share at least one. I have.



More reading is always good, but one must read with a critical eye. Not everything is accurate or useful. One can blind copy other things besides piano scales.