I am going to replace the tuning pins of a C. Bechstein upright which are loose. So it is a good time to restring/rescale the piano. It is a great instrument, but I've heard better scaled vertical pianos, an August Forster studio for instance.

So I was wondering if I could improve the scale of the piano.

In comparing the two instruments, The August Forster has a better tone in the bass and a better balance in the acoustic power between the bass and the treble.

The C. Bechstein sounds like an old piano and I want to get a more modern sound/tone/tuning. Also the bass is much more powerfull than the treble and I am wondering if I can obtain a better balance by rescaling.

I bought the book "A Guide to Restringing" but I was deceived by the contents of this book. It says nothing about piano tone nor about longitudinal modes.

I've heard what the tuning of the longitudinal mode can do to improve the sound of a piano, by deliberately choosing/changing the relative diameters of the core wire and copper windings.

See here

I am not going to replace the bridges, so I can not change the length of strings, I can only modify the diameters of steel and copper wires.

Is there any book I can read about scaling a piano taking into account the longitudinal mode?

Is there some software available to do the math?

I am unsure we have much control on the longitudinal modes, for the basses possibly, I seem to recall that some combinations are avoided not that the mode is really computed.

all parameters being related , scaling is more the lenght of strings than the real scale.

if you work on a low tension instrument with uneven strings lenght within the unison as a Bechstein, a large part of the original tone will be retained most probably (high iH and very open unisons)

longitudinalmode can be used to "measure" the elasticity module of the steel on a tensed string, rubbing the string with a rosin impregnated cloth and measuring the pitch heard (the longitudinal wave pitch) the result in Hz can be compared to the lenght and diameter of wire, so to have the MOE number with some approximation

You can also experiment by changing the original pitch of the string, the longitudinal will stay the same

The formula is at the end of that book : http://www.lulu.com/shop/jean-louchet/the-keyboard-stringing-guide/paperback/product-6472282.html

A good lecture even if practical aspects are not all covered


P.S I believe that the formula used by Hellerbass when computing a new bass strings set is taking in account longitudinal mode, but I am not really sure of that

There is a lot more to tone development than just the stringing scale. There are probably several reasons why your C. Bechstein sounds different than the August Forster. You don’t say how old the C. Bechstein is but it might sound “old” because it is old. Soundboards change—generally losing some of their stiffness—over time. As do hammers.

There are probably a number of design factors involved as well. Without a detailed analysis of the two different pianos it is impossible to determine even the basic reasons why they sound so different. Aside from any age-related changes the soundboard designs are probably some different as well. Soundboard grain angles, root thickness and tapering, rib placements and dimensions are also probably different. Bridge designs may differ. Backscales may differ.

In other words, it is almost certain that you can improve the stringing scale on the C. Bechstein but don’t expect the new scale to do everything. Don’t be tempted to raise the tensions of the tenor or treble to increase the piano’s “power” in those areas. Aside from endangering the structure of the instrument you may do quite the opposite; you may actually decrease its power potential. If anything, look for ways to decrease the tensions while keeping things balanced.




Yes, there is a book on the subject. It is called Longitudinal Modes In Piano Strings by James F. Ellis and is available from the Piano Technician’s Guild. Go to www.ptg.org.

It is, however, a very complex subject and, when you have finished reading the book, you will discover that there is little you can do to effectively “tune” the longitudinal mode harmonics in your piano’s scale.

Nor do you really want to. All piano scales are compromises in one way or another but the compromises necessary to tune the longitudinal mode harmonics make what are usually considered to be unacceptable variations in string tensions and/or inharmonicity (stiffness).




I don’t know of any commercially available software that includes routines for calculating or “tuning” the longitudinal harmonics of piano strings. There are commercially available programs designed to help you develop a new stringing scale—i.e., wire diameters—to fit on your piano. One such program is available free online. Go to www.scaleripper.com/

ddf

The pianos are made by two different companies would be a basic reason to begin with. So the designs would vary slightly and that would be another basic reason.

You will not be able to buy basstrings made for tuning the longitudinal mode. It turned out to be too difficult to make these strings, too many failed to make one string, so the strings would be much too expensive.

There is quite much though that you do to change the string design. Here is one book you could read:
http://www.amazon.de/Praxisorientierte-Mensuration-mit-dem-Computer/dp/3923639937
I have many years of practical experience using this program and find it very usefull.

but the book is only in German, and so is the software (is there an updated version ? mine was under MS Dos...

I recall there was an "iH match" option and that the finall mass of the wire was an important parameter, but I was not knowing enough in those times, to make a good use of the program (and now I lost it , while I have seen it is yet at the Renner catalog)

In my opinion, some bass maker use the Tf/65 slide rule from Klaus Fenner (sold with a book , both are probably not availeable those days, but I saw a pic of the rule on a web site collecting specific slide rules)

@Gadzar, depending of the era of your C Bechstein, what you could have to do is adapt the scale to the available wire today

Bechstein where never representative of pianos with a clear thick singing treble, but the wire quality they used allowed for a nice tone. Roslau would make it rounder but some "bite" will be lost

Tell me about Poehlmann wire and I buy all the stock (despite it may have hardened with time ?)

Yes Kamin, there is an english version of the software.
I keep an old dos PC just to run this software, but you might be able to run it in a virtually dos under Windows.
The Tf/65 functions are also in the software.

K.Fenner analyzed the piano scales by their iH range, related to tension level

3 ranges, medium as Yamaha and Steinway, medium tension
High tension low iH as Fazioli

Extra high iH as Bechstein (together with low tension but I am unsure in the end as I have seenn some Bechstein scale with a classical tension)
At some point the wire was extra hard, also, hence high iH (turn of 1900 I suppose)

I can't help wondering if, after changing the scale, the bass section will blend with the rest of the piano? I'm always impressed with the improvement new strings bring. You might want to install new strings before you calculate the amount of change you want to make.

Ah , thank you very much, who is selling it ?

If I get it could you help me at large with the book ? (I could find some german customers to help me but the technical words I am unsure they can get)

Traditionally the Bechstein instrument had a booming bass and a weaker, thin treble because the instruments have a sounding board that is thicker and more stiff in the treble. There are no secrets about this, it is their design.



I have some rolls here from the 30’s and 40’s and some from the 70’s. Not sure what kind of shape the wire is in.

Why do you wonder? Are you familiar with scale constructing?

Yes Isac, I can help you with the book.
I do not know who sells the software. Ask the man who made it.
I will send you his mail adress through the Forum.

The C. Bechstein's S/N is 38747, it was made in 1896, 50" tall, full upright, under-dampers, over-strung, 88 keys, 26 bass, 15 single wound monochords, 11 single wound bichords, and 62 plain steel trichords.

The August Förster: S/N 84188, made in 1950, 46" tall, studio,under-dampers, over-strung, 88 keys, 31 bass, with double wound strings in the low bass, 57 plain wire trichords in the treble.

They are absolutely different pianos, but despite the small size of the August Forster, bass notes are deep, very clear and enough powerfull. The balance between the bass and treble is really arresting.

As I said I am only replacing the tuning pins and strings, I will not dare to mess with the bridges. Nor the hammers, which are in good shape.

Shaping and voicing the hammers will improve the tone of course, but I am wondering if by carefully choosing the diameters of the new strings I can achieve some improvement of the tone and balance.

So, do you think it is not a good idea, for me as a beginner, to change the original diameters of the bass strings?

Not at all. I think it quite possible for you, as a beginner, to tackle a project like rescaling your piano. I just think you should not get into trying to incorporate the concepts of controlling longitudinal mode harmonics into your first effort. Or perhaps not ever. Consider that I make my living designing and redesigning pianos and I rarely get involved in calculating longitudinal mode harmonics. There are other string parameters that take precedence.

Do some study on piano scaling and become familiar with some good scaling software. I’ve suggested one—ScaleRipper—that is available as a free download. There are others available for purchase. Or, if you are adventurous you can study the available mathematical formula and write your own. Measure and practice. When you’ve worked out what you think is a good scale for your piano, run it by someone who is already familiar with piano rescaling and see what they think of your efforts. This person may charge for his/her services but if that person is knowledgeable about string scales and is able to prevent you from making a serious mistake it will be well worth whatever fee is charged.

Your scaling goals are—at least should be—simple. You don’t want to dramatically change the character of the piano. You want to refine the character that is already there. Usually the weak part of most old scales is the bass. They were nearly all developed by trial and error. With a lot of emphasis on the “error” part of that statement. Modern mathematical tools help us reduce those errors and give the piano better timbral balance. You can almost always improve the overall performance of the bass section and give the piano more smoothness across the bass-to-tenor transition.

Good luck and have fun on your adventure.

ddf

You may be able to wind with very thin copper, I suggest that bass winding is a little like voicing, you need to make so much sets to begin to be proficient.

Also understanding the basics in tension progression and strings stiffness (plus "solicitation" ) is helfulo, as knowing the usual levels of iH find in pianos.

the strings where more or less similar to the one availeable today, that have also to be understood , the lenght of the strings allows for some kind of wire, on old instruments very often, using Roslau wire will rise the iH and lower the constrain more than wanted.

At last in the basses as tension is high those parameters often can stay within the acceptable range.

You plan to wind the strings yourself is it ? if not the reputed bass makers already optimize your set.

good luck, that is anyway the opportunity to learn more in the fundamentals of piano design

DEl, I was surprised to read from you in a post that you aim for an even tension along the scale, I suppose I did not read correctly or you where talking of something else.

or simply that mean evening the tension progression, is it ?

Evening out -- smoothing out -- removing the abnormal peaks and valleys typically found in old scales.

ddf

Hi pianolive, if I read correctly, you own the book "Praxisorientierte Mensuration mit dem Computer". Can you tell me, if the software "Turbo-Mensuration" is included?
@Isaac: Have you bought the book in the meantime?

Hello, I m pretty sure I have that book somewhere, but I did not find it yet.

The software, I had, it was 20 years ago on a 5' floppy

If I understand well there are 2 computing methods, , one is the TF 65, developed by Klaus Fenner, the other is the one from Peter Tholey.
AT thoses times only one kind of piano wire was taken in account (Roslau) I dont recall any possibility to enter a different one (more hard, or less, different carbon content, or/and differntt annealing) The one I find that try to give comparisons between different and original type of wire is named Bonamens, and did not obtain any success, may be because it was not advertised much, only used by the "pure sound" people...

Too bad, as this fine development could behave evolved , little bugs fixed, I never understood why such a tool did not receive more aknowledgment (there is even a forum, empty)

http://www.bonamens.nl/component/option,com_frontpage/Itemid,1/lang,en/

For my recent (and first ) restringing, I created an Excel file and optimized the tension and inharmocity based on the original wire sizes. That worked quite fine, but I thought, a software supporting this task would be fine.

I will check Scale Ripper.

We have a particular problem in France with French pianos, that where stringed with piano wire having a lower MOE than Roslau or US wire , so the iH was lower originally (and constrain was often very high) more gauges than with Roslau or actual system, so there is a better evening in the thickest diameters, but a large part of the particular tone of French pianos was due to that wire (Firminy wire).

Different hardness depending of the era, probably, but in any case the metal was certainly excellent.

Those wire could be find (rarely) on restringing jobs up to the 60's, as the product was yet sold, but many where using Roslau wire yet.

Mounting Roslau on some of those scales lend to a nasal underconstrained wire with too high iH.

We dont have such a problem with most old German pianos

I can not answer your question, but I thank you for the pointer to the 5 lectures.
Although presented 25 years ago I found the content interesting, maybe I will understand more of it on subsequent readings (-:

They are good but new theories came later, I cannot go in details but that research work is far from being finished.

One could "ASSUME" that research has continued, or that the demise of the piano's popularity has caused the topics to be abandoned.
Advances in computer modelling would suggest that the subject could be explored more economically now that 80s era super computer power is available in laptops.

I am very much interested in the later work.
My background is in engineering, not music.
I can grasp the physics and math while TRYING to appreciate the musical aspects (-:

Thanks,

There are some references to l-modes and l-waves in the "Quadra(tic) effect ..." thread.