Piano World Home Page Forums Our Most Popular Forums Piano Forum FAQ - Piano Forum what is a high tension string scale?

It's always an education hitting different piano dealers. This particular one (Vogel,Schulze-Polmann) was decrying the 'high tension string scale' used on Pacific Rim pianos. Is this just sales jargon? What are the sonic tradoffs/implications of Low vs. High tension designs?

It is a sales jargon term that has no meaning. Below is an answer I gave earlier:

I have never gotten a definition of "high-tension/low-tension" that makes any sense to me. So I am suspicious whenever anyone talks in those terms.

In general, the longer the piano, the longer the strings. It is a physical law that the longer the strings, the higher the tension the strings need to be to give the same pitch. Also, the heavier or thicker the strings, the higher the tension needs to be to give the same pitch. These are physical laws, regardless of the make of piano.

To the best of my knowledge, every piano manufacturer has used heavier strings the longer the piano. Even without that, no matter who made the piano, bigger pianos would have higher tensions than smaller pianos, just from the length of the strings.

There are a couple of rules that should be followed. The most obvious is that you do not want the tension near the breaking strength of the string. In fact, you want it under the elastic limit of the string, which is about half the breaking strength. This is usually not a problem, except that the breaking strength will usually drop considerably when you go from the plain wire strings to the overwound strings.

The other rule is that the tension should not change a lot from note to note. Everything else being equal, lower tension will not be as loud, and it can be boomier than higher tension. This may not be noticable if you have gentle transitions from one area of the piano to the next, but big jumps and rapid transitions can be heard.

Unfortunately, when calculations were more laborious than with today's computers, when most manufacturers did not see the value of designers that were as adept with the slip stick or log table as they were with the french curve, there were some seat of the pants practices that were pretty much ingrained in piano design which were not ideal, and in some cases, pretty bad. These include changing the wire size too often at the top of the piano, and not changing it enough near the transition to overwound strings. The result is a scale which is way too high in tension just below the top octave, and drops way too low in tension way too quickly near the transition.

Careful redesign should give tensions that avoid too high tensions, and in shorter pianos, drops gently to near the tension of the overwound strings, or rises equally as gently in longer pianos, and avoids any big jumps anywhere in the scale.

Thanks for the response. If I'm reading you correctly, higher string tension pretty much comes with the territory when you increase the mass of the string - either by lengthening it or by overwinding it. Since overwinding is the ONLY way to get bass strings of reasonable length (short of having a 25' grand piano) I would think that shorter string scales will by definition be higher tension than longer ones.

I think you are oversimplifying the relationship in a way that is not particularly meaningful.

Saying that shorter string scales will by definition be higher tension than longer ones is only a theoretical notion. The real-world bottom line, as BDB has already said, is that describing a scale as high or low tension doesn't have much meaning. It's really just a marketing thang.

It has always been my understanding that the strings in a piano are all tensioned about the same in relation to their breaking strength. Extensive experimentation in my lab has confirmed this. Ostensibly, to get the best tone and sustain, one wants to create the highest tension that is safe, which would be some small margin below the yield strength of the steel (the point where the material stops returning to its original length when released).

This requires that the string weights be designed lighter (mass per unit length) as piano models grow in length. This is why longer pianos have more unwound, bare steel strings in the bass than shorter ones. If a nine-foot piano were strung with bass strings as heavy in diameter as a six-foot piano, only longer, they would certainly break long before the proper pitch was achieved, since they would be a full three feet longer. In fact, it would require a tension a full 2-1/4 times greater!

The copper windings don't add any enhanced quality to the sound of a piano. Increasing of string mass is needed to remedy inadequacies due to shorter piano lengths.

Don
Kansas City

Interesting thread. It seems that the ideal piano regardless of length would have nearly every string a different gauge (mass per unit length) throughout the scale. If this is even partially true, are there any pianos that come close to achieving this? Could this perhaps be a differentiator between what are the best and those less than the best?

Interesting idea. What would be YOUR notion of the ideal piano?
This needs to be nailed down. To my mind, every piano is a compromise of some sort; it is the nature of each compromise that gives different piano designs their individual character.

Yes, in good pianos the string guage changes frequently, every few notes, along the scale. Some restringers rescale pianos to increase the numbers of graduations in string guages with the notion of making the pianos easier to tune, and perhaps, in theory at least, better-sounding.

Your idea is another variation on the common theme here of trying to find out what single factor(s) are out there to define piano "quality." I don't think there are such single factors; there are multiple factors.

As I said, most pianos were strung according to custom, rather than science. Variations in gauge are less significant at the top of the scale than they are at the bottom of the scale, and indeed, bass strings do change at every note. A pity that scale designers did not take their cue from that, and changed their gauges more towards the bass and less in the high treble.

Pianos designed more recently tend to do better at this than more traditional designs. To my mind, traditional designs rescaled with this in mind tend to sound better than with their original scale, and need less voicing.

The strings in a piano are arguably one of its cheapest parts. Strings are largely the same between brands. Most of them are simply a piece of wire. Piano string manufacturers like Mapes will copper-wind strings any way you want for a reasonable cost. To have string designs identical to a Steinway would merely require measuring the strings and copying them. Big deal.

It seems to me that other factors are much more responsible for the quality of tone in a fine piano. The soundboard, bridge, and rim would be where the real craftsmanship takes place.

Don
Kansas City

Don, I respectfully disagree with your dismissive conclusion about the strings. The string is where the sound originates. Some manufacturers wind their own strings. Plus there is the whole metallurgy behind the strings as well as the copper winding itself. I do not disagree about the craftsmanship in the components you mentioned. The piano is after-all the sum of ALL its parts.

Mike, I wholeheartedly agree with you about there being multiple factors.

You did ask me what my notion of an ideal piano. Since you asked, first it must be acoustic and in that fact not much different than existing technology. It must tune itself, have variable hammers (different tone), variable touch, adjustable sustain, adjustable harmonics, very durable (100 years at least), allow recording without any alteration of touch, practically infinite repeatability, etc.

My thought about the strings was one more of creating another attribute which can be used to objective compare one make against another. I will also admit that doing so probably is fruitless. I just can't get the systems analyst out of me.

Piano wire is piano wire. It is simply high-carbon, spring-tempered steel. It was chosen because it has the highest tensile strength of any common material.

When you break a string, and your tech replaces it, he uses piano wire from a generic spool of the appropriate gauge. He puts it in and it sounds just like the old string (or better if the old one was dirty/rusty). A Yamaha sounds different from a Bösendorfer because of its design, not because they use a different type of material in their strings. Otherwise techs would have to keep special spools of wire from every piano manufacturer in the world.

I have literally broken thousands of strings in my experiments. I have had every sort of experimental string made. Strings with different windings, special coatings, etc. Good ol' bare steel with good ol' 99.99% electrolytic copper is the best. The combination is the result of 300 years of evolution and everyone does it essentially the same way.

Don
Kansas City

I have obviously been duped by the "German Piano Wire" marketing ploy. Thanks.

Not exactly. Piano wire evolved according to the needs of the piano industry. Tensile strength increased quite a bit during the 19th century. Pianos provided a good test for the quality of piano wire.

Steel is very elastic, which is another quality that is desirable. Breaking (tensile) strength should not be the limit of tension on a piano string, actually. It should be the proportional limit, the topmost tension at which string stretches proportionally to tension.

But the result of the developments in the technology is that most piano wire has very similar characteristics these days, and there is not that much difference between different manufacturers.

Very good points.....actually, there is a lot more to the art of string making, especially bass strings. I have been doing some research on this very subject in reference to my M&H 7ft grand. The type of copper used for bass strings makes a difference in the sound. The type of core wire used also contributes to the overall sound because different sizes of core wire, their thickness, along with the type of copper used in the windings, the way it's wound, by hand or machine, all these factors relate to the thickness of each graduated bass string, hence you have very different "scales" for each model piano. Another factor in the core wire is how far it will stretch before breaking...the better quality wire has a higher breaking point. I have been told that for instance, Mapes Gold is a much better wire because it has a higher streching/breaking point. All these factors help contribute to the overall sound of bass strings.

Gpman

So, you're saying that if a piano was designed for special, high-strength strings so that they could be brought to a higher tension at manufacture, then when a tech orders ordinary replacement strings for that piano, they will break?

Don
Kansas City

eromlignod, from what I have learned, say Maypes Gold wire was used for the core wire of all the bass strings, and then you replaced a broken bass string with a different wire that does not have the same properties, ie the stretching/breaking point is different, when you pull the sting up to pitch or past the correct pitch, it may be stretching the string past it's optimum point and it will either end up sounding dull or it may break...it will never go back to normal after stretching it past it's optimum point....that's my understanding...perhaps someone im the string making business could chime in here who knows more about this.

Gpman

(This is from my guitar expereince, so it might not be the same) but all strigns are not created equal. Yes, the unwound strings are mostly the same and they can be interchanged very easily(made from sweedish steel for guitar), but depends on the compoisitions of the meatal and quality,it does sound very slighly different.

It is the woundstring (bass stirngs) that has the biggest effects. Whether the core is round, octagonal, how big or small makes a difference. Also the cooper wrapper material (bronze, phosphor bronze, brass, nickle, nickel plated steel, stainless steel or even gold!) makes difference. Also on whether it is flat wound vs. round wound.

Depends on all that, some strings sounds brighter and more percussive or soft and melow and etc.

Then perhaps I've not been duped then

I second having a real "string guy" come in here to provide more background.

Overall, in looking at the active components of the sound mechanism being the hammer, string, bridge (that being any part of the piano which transmits vibration from the string to somewhere else) and lastly the soundboard, it would be hard to imagine that some variation in the string geometry, metallurgy, gauge and length doesn't have some effect on the tone that is personality of the instrument.

I'm glad you said that so I don't have to feel guilty for asking an otherwise off-topic question of eromlignod.

Don, any news on the development of the self-tuning piano? (I was thinking about your work last week and wondering.)

Guitars are a little different than pianos. You don't replace all the strings in your piano on a whim to get a different sound. If a piano string breaks, you call a tech and he simply replaces and tunes it.

My point is that the tensions of piano strings can't vary too wildly from design to design since this would necessitate special proprietary materials for each type, which isn't the case. I don't have my notes with me now, but I believe that the tension of piano strings is around 150 lbs. across the gamut.

Don
Kansas City

Actually, I should have some very exciting news shortly. I am currently in the process of changing manufacturers.

QRS just couldn't keep the project on track. Every time they said it was active again, they would put it right back on the back burner. The last straw came when I received a shareholders' report that announced some of the new products that they were introducing (that had been preempting my invention). One of them was a keyboard that had black keys that "light up" when you play them...oh brother.

The vice president of a large piano company that you all know quite well (no hints just yet!) is coming out for a demonstration in the next week or so. He is very excited about the project and I'm sure he will be duly impressed with the prototype.

Ironically, since the project has sat dormant for these four years, I have continued to improve it just to fight the boredom! As of last night, I can tune a string that is 45 cents out of tune in nineteen seconds (five seconds to bend 45 cents, and fourteen more seconds to stablize). The accuracy is plus or minus one-sixth of a cent. Interestingly, I can actually measure and control the pitch much more precisely than that, but the string has a natural tendency to fluctuate by a few tenths of a cent anyway, so you really can't tune it much more accurately even if you wanted to.

After my upcoming meeting I'll make an announcement in the group. Thanks for your continued interest.

Don
Kansas City

I'll look forward to the announcement, Don. My only reservation about the idea previously was that I wished it were being implemented on a better line of pianos.

Oh, it's a better line of pianos all right...

Don
Kansas City

Sorry, but am not familiar with your work Eromlignod..what is it that you are working on?

Gpman

The self-tuning piano.


http://tech2.nytimes.com/mem/techno...3FF931A35752C0A9659C8B63&oref=slogin

http://www.npr.org/templates/story/story.php?storyId=878091

http://www.newscientist.com/article.ns?id=dn3143

Don
Kansas City

Thanks, and the best of luck with it! I wish it could be installed in an existing piano

Gpman

The relationship between scale tension and timbre is not quite as indefinable as some would have us believe.

BDB is right when he points out that many, if not most, of the string scales found on pianos in use today—including some very highly regarded pianos in current production—were developed empirically by designers who had only a vague idea of the scale tensions they were ending up with. By the time the meetings that formed the basis for the book, Piano Tone Building, however, at least some designers had a pretty good grasp of the relationship between string scale tensions and the voice of the piano. They were also aware that a change in scale tensions required appropriate changes in the soundboard design.

When considering just what effect variations in scale tension might make to the overall voice of a piano it is important to understand that changing the tensions of one or two notes in the tenor (say, by replacing the original strings with wire a half-size larger or smaller) is not going to make much difference. Restringing the whole piano and raising or lowering the average tenor string tensions by 10 or 15 lbs. probably will. (If you’re raising the tensions by that much you might also want to consider where you want to be when the plate lets go!)

Many scales in use today are hard to classify in terms of scale tensions. For example, C-52 in one version of the Steinway Model D has a tension of 166 lbs. (343.5 mm, #16 ½ wire). That is just on the high side of what I would call a low-tension scale. One octave down, (C-40) we find a tension of 179 lbs. (660 mm, #18 wire). That’s toward the high-end of what I would call a mid-tension scale. Going one more octave down, (C-28) we’re up to 206 lbs. (1291 mm, #20 wire). Now that is high-tension in most everybody’s book. So what do we call this piano? From C-52 going up to C-64 we find tensions also going up, this time to 172 lbs. (184.5 mm, #15 ½ wire). At C-76 we’re all the way up to 186 lbs (98.6 mm, #15 wire). And, finally, at C-88 we find the tension back down to 154 lbs. (49 mm, #13 ½ wire). So, this scale is all over the map. If we sum and average all of the unison tensions in the piano we come up with a total scale tension of 45,700 and an average of 188 lbs.—definitely a high-tension scale.

In terms of how scale tensions affect the voice of the piano, however, the strings that lie on the long bridge have the greatest effect. In the case of the Model D this averages 179 lbs., still quite high.

Nor can we say categorically that long pianos have high-tension scales and short pianos have low-tension scales. While a Steinway Model M would probably average out around 150¬–155 lbs., I have a 5’ 2” Knabe in my shop which averages 170 lbs., and that includes the top treble section where tensions are down in the 120 to 130 lb. range. The tensions through the tenor section of this piano average 178 lbs. Just one pound shy of the Steinway D average.

Does this mean the scaling of the 5’ 2” Knabe equal to the scaling of the 8’ 10 ½” Steinway? Not really. C-40 in the Knabe is 665 mm long and uses a #18 ½ wire for a tension of 190 lbs. Not all that much different. But in the Knabe C-28 is only 1025 mm long and uses two wrapped strings.

So, what does all this mean? In general, if all other factors are equal—string length, hammer density and resilience, soundboard design and construction, etc. the sound envelope generated by a low-tension scales will have more energy in it fundamental and lower partials. The sound envelope generated by a high-tension scale will have less energy in the fundamental and more energy in the upper partials. Also, very generally, strings at a higher tension will have the capability of storing more energy so they have the potential for more sustain.

However, all other factors are rarely, if ever, equal! String lengths can vary. A high-tension scale might use relatively short strings with large diameter wire. Or it might use relatively long strings with smaller diameter wire. And a low-tension scale also might use relatively short strings with larger wire or relatively long strings with smaller wire. Each will produce a different sound envelope.

Still, while it is impossible to categorize these things absolutely, it is possible to put forth some broad generalizations. If a designer wants to create a piano with a warm voice with broad timbre dynamics he or she will probably chose a relatively long, low-tension scale. This will work against a relatively low-mass soundboard of medium to low stiffness. If a designer wants to create a piano with great power he or she will use a higher-tension scale working against a more massive and stiffer soundboard system.

Some final thoughts.
Except in an abnormally long high treble and in a poorly designed bass scale string tensions will not approach a strings tensile proportional limit.
Generally, when a company announces that they have “increased scale tensions for more power,” they have done just that. Depending on how creative they are this will be done by going to larger wire sizes through some parts of the scale or by making the strings through all or part of the scale longer. Occasionally, both. Whether this actually gives them more power is another issue. If things are going to be kept in balance ribbing will have to be slightly stiffer, they might have to increase the thickness of the soundboard slightly and they may need a slightly more massive hammer (along with the resulting deformation of action parts). The higher tension scale will also tend to resist soundboard mobility (think of it as pushing against a stiffer spring). More than one pseudo-designer (usually someone in the marketing department) has been surprised to find out that simply increasing string tension does not yield the intended results.

Del

Del, thanks for your great explanation. What you are saying follows the logic of the string maker I was talking to.

In doing research as to what the best bass strings would be for my 1925 M&H RBB, I was told that having the exact string specs from a 1925 BB would be the most beneficial and that M&H had a certain bass string core wire and outside diameter wire in mind when they were designing the piano? I was able to find the exact specifications of a set of original strings on another 1925 BB, thanks to an owner of a 1929 BB who has the these exact size strings, core diameter, outer diameter etc. I have sent those to the string maker. For the most part, he says they are good, and he is only going to change a few of the parameters, including a smoother transition between unicords and bi-chords.
The new set of bass strings that are on my RBB now do not sound good, giving a thin, hollow sound. When my rebuilder measured the core diameter of the lowest note, it was .048. The lowest core diameter from the original set of 1925 strings was .059, that is quite a difference. In fact, all the core diameters of the current set of bass strings are smaller than the original specs...I suspect that is contributing to why the bass does not have a rich, robust sound?

I guess M&H knew what they were doing back then and knew what bass string specs would sound the best with their soundboard design.

I know there are string makers out there that design "scales" for these older pianos, changing the original specs, thinking they will sound better than the original scales...and sometimes they are not successful....interesting!

Del, have you used a lot of original bass string specs in your rebuilding of older pianos, and if so, have you found they sound optimum?

Gpman

There are a variety of ways of computing averages, including average tensions. Adding all of them up and dividing is one way, but it tends to throw things off if some numbers are way out of whack. If you graph the tension of note 88 and the tension of the first overwound string, and draw a straight line between them, and take the midpoint of the line, you probably get a better idea of what the ideal average for a given scale would be. Of course, many pianos are nothing like that.

The model that I was using is based on this straight-line method, and in this model, the line for a short piano tends to decline a bit towards the bass, while in longer pianos, it rises.

In the case of Del's Steinway D, the tension probably conforms reasonably closely to this model. In the case of the Knabe, the tension undoubtedly steps up in random jumps according to changes in wire gauge until it nose-dives to, or more likely well below, the tension of the first wound string. (Whenever I hear people say that the new Knabes use the scale of the old ones, I cringe, knowing that they could, and probably do, do better!)

A bad break more than likely comes from diverging too much from a straight line or a reasonably smooth curve. A lot of other problems do, too.

Del;
As always your responses are an education for those of use struggling to understand the intricacies of piano design. Thank you very much

DMR

To get an idea of how the scale is loading the soundboard you have to consider unison tensions. All of the tension of the individual string are added together. When I’m analyzing a scale I look at a variety of things. These include the overall tension of the scale (This is the number most often used to impress non-piano folks. The Steinway D I mentioned has a total of 45,700 lbs., the Knabe 37,850 lbs., the difference being mainly in the low tenor and bass.), the unison totals for each section, graphs of unison tension, string impedance and inharmonicity, backscale lengths, and rows and rows of numbers. All of this must then be considered in reference to the soundboard design, whether the original is being used or a new board is being installed. It is also considered in reference to how the original piano sounds—assuming the piano is in good enough condition to tell.

It is rare to find an original scale with anything like a straight line anywhere in the scale. Most are quite erratic starting fairly low in the treble, rising through peaks and valleys to top out somewhere toward the mid-tenor then dropping precipitously toward the bass/tenor break. The bass is usually equally varied, often with no discernable method to the pattern.

Of the two pianos I mentioned the Knabe actually has the more uniform scale through the tenor and treble sections. The bridge has a more uniform sweep and the scale uses half-sizes throughout. It does, however, take a huge drop from G#-36 (188 x 3 = 564 lbs.) down to G#-24 (144 x 2 = 288 lbs.). The original bass/tenor break was fairly smooth by itself, but the voice characteristic from G#-36 to G#-24 changed dramatically. None of the aggressive hammer voicing techniques evidenced in the hammers had helped. Tension then levels out some before heading back down with the mono-chords, ending up with 188 lbs. at A-1. From C-88 down to G#-36 the average unison tensions in the Knabe are very close to those of the Steinway D.

With the use of new tenor and bass bridges the scale tensions of the Knabe are being brought down to 155 -165 lb. range and the bass is being brought up to better blend with the tenor scaling. The overall tension load will be 37,260 lbs., just a bit lower than the original but with much better balance. The soundboard assembly is being designed accordingly.

Like BDB, I cringe when I hear manufacturers (not just Knabe) bragging about using original scales in some resurrected piano. We can do better and the piano buyer deserves better.

Del

Do not the force on the bridges vary, independently of the string tension, but because of height of bridge?

I thougt this was teh main issue with low or high strung pianos. But this is perhaps a different topic.

The last Knabe (5'-8") I restrung I did not bother to note the original scale, since I am aware of their deficiencies. But although Knabe did use half-sizes in the low tenor, I found that I could get a smoother scale using whole sizes. If there is an extreme foreshortening of the scale, sometimes you have to skip a half-size there, or even more. I aim for a low deviation, and in the case of this Knabe, it was less than 4 lb. The top of the scale, about the last 2 octaves, are all strung with the same size wire, showing that the designer aimed for the theoretic geometric curve in the bridge, and then screwed it all up by changing gauges.

That piano is a whole other kettle of fish or something. This piano switches to bi-chord wrapped strings fairly high up in the tenor. The new scale will be switching ever further up and they will be placed on a transition bridge.

Your point about whole wire size changes is well taken, but it really applies only to the lowest part of the tenor bridge and then only when the bridge has been foreshortened a fair amount. The rest of the scale is generally better off using half-sizes.

Del

They are interdependent.

If you replace a set of strings with higher tensions (i.e., larger diameters) on a given piano and make no other changes the string deflection angle across the bridge will be less than it was originally. The more taut string would require more force from the soundboard/bridge assembly to deflect it the same amount.

Del

Del, it sounds to me after reading your posts, that the original string scales can be improved upon? I believe that is what will happen with the new set of bass strings I will be getting for my RBB.

Thanks again for your excellent posts.

Gpman

Yes, almost always. My only warning would be to have the scaling done by someone who knows what they are doing. You want someone who is more cautious than brave. The idea is to even things out and correct for obvious scaling flaws, not try to make it into a whole other piano.

Unless, of course, you are trying to make it into a whole other piano. Then it is always safe to decrease string tensions -- rarely is it safe to increase them. For example, I am reducing the tensions through the tenor of the little Knabe I've been talking about, since the plate was obviously strong enough to hold the original higher tension scale this will be perfectly safe. (I'm also designing a new soundboard to work with the reduced scale tensions.) I would never increase the tensions on, say, a Steinway S, M, L, O or A. These plates were designed to work with relatively low-tension scales and I would not want to over stress them with a higher tension scale.

Del

Thanks Del, I belive that is exactly what will be done with my bass strings...his calculations actually follow pretty close to the original scale, but he sees the areas where he can improve in order to smooth out the breaks etc. He is definitely not going the route of changing the scale to make a "new" piano.

Interesting, I always heard that Steinway was a high tension piano..

Before doing all this research on bass strings and reading your posts, I did not realize how complicated and important stringing a piano can be. It can alter the sound quite a bit.

Gpman

Thanks, Del and others for the informative thread.

Half-sizes may be better lower in the tenor, but without adding more hitch pins, one must take an average. The point is that to get a better scale, you usually have to change gauges more often the lower in the scale.

This is a comparison of the before (top) and after tensions on the last piano that I restrung. The lowest notes, on the left of the graphs, are the highest wound strings. The first pair of plain strings are 2 full sizes heavier than the next pair. But it still should be evident which should be the more even scale. (The peak at note 87 is probably just the result of a slight inaccuracy in the measurement of the speaking length.)

Interesting graphs, BDB. Can you characterize the change in sound from the revised scaling?

Not exactly, because it would be comparing old strings with new ones. Still, there are some trends. The biggest difference is less of a fall-off of volume as you approach the break. There are some pianos that have a great deal of inharmonicity near the break, and scaling this way improves that problem greatly. They are much easier to tune. Some scales have problem areas which clear up. Of course, with more uniform tension, the piano stays in tune better.

I suspect that problems with what people characterize as the "killer octave" may be the result of bad scaling in that area. As you can see in the top graph, the tension was extremely high in that area, meaning the strings were very thick for their length. That cannot be good.

This piano has the original soundboard and bridge, about 80 years old. The work was done on-site, eliminating moving costs. The question of the effect of soundboard design on sound is much more difficult. Rescaling takes just a couple of hours to measure the speaking length and stare at the numbers to come up with something reasonable. That is cheap enough to do even for a small improvement. Replacing the soundboard would double the cost of restoration with no guarantee that there will be a significant improvement. That makes no sense.

Thanks BDB, very interesting......one of the big decisions I had to make was whether or not to keep the original, already repaired soundboard and bridges. In the end, we kept it, because it had excellent sustain, good crown, and the piano sounded very good as it was....one of those cases where it made no sense to replace it since it was functioning properly.

The fellow I received the original scale from said one of the important factors was to get the core wire diameter correct, and that seems to be part of what your saying here as well, in order to get a good and even sounding scale.

Gpman

No, I have not delved into bass string design. Again, too many factors to be certain of the results. For the most part, the bass string manufacturers know their business fairly well, often better than the piano designers.

While many pianos do, indeed have relatively poor scaling through the fifth and sixth octaves, many more do not. The abnormally percussive attack coupled with a too rapid drop-off is a soundboard issue. It is not something that can be solved by either scaling or hammer voicing.

Soundboard replacement—when necessary—does solve the problem and the results are quite predictable. Assuming the shop doing the replacement knows what it is doing, of course.

Del

Most string winders, such as Mapes, follow factory specifications pretty closely. They will custom wrap, but they clearly don’t want to. Others, GC Strings in Canada among them, wrap to their own specifications which may or may not follow factory specifications. If you order from them you get what they want to wrap with little say in the matter.

There are several other string winders — Jim Arledge is one of them — who can help with bass string scaling if this is not something you want to do. As well, there are several rebuilders who offer string scale calculation as part of their business.

Bass string scaling is not all that difficult to learn and many improvements can be made here. Essentially is it a question of working out the ratio between core wire diameters and overall loading to achieve a desired balance in between string tensions, string impedance and inharmonicity.

Del

I suspect that almost everyone who replaces soundboards knows nothing about the design of them, and just replaces with a copy of the original. How many people do you think there are in the world who could do otherwise? (And do they agree on the solution?)

I suspect that they follow industry standards. However, factory specifications are not likely to be available for enough pianos that they would have to be able to design strings on their own very quickly.

I found this website very informative:

Gpman

Seems like piano as a hobby has bacome science of physucs.

I just wonder how many older pinos soun fantastic in my ears, and new also, despite the obvious imperfections in their design.

Like Bechstein claims - "we don not make techncal instruments, but musical, good sounding, pianos".

And, as pointed out above, some problems are not due to bad scaling, but are sound board issues.

The soundboard is the soul the piano (Vincent Chavanne). I have heard that the result soundboard replacement is very hard to predict.

I have a question...would a properly designed bass string scale have an effect on the overall sound of the piano in relation to what the rest of the strings are doing? Is there a synergy involved?

Gpman

I have no idea how many rebuilding shops there are world-wide that are competent enough to replace soundboards. I expect there are probably fifty or so in the U.S. And, as pianos continue to age, the number is growing. You might check out the upcoming PTG Conference in Rochester, NY which will have quite an emphasis on soundboard technology.

Mapes has the original bass string scaling for a vast number of U.S. built (and quite a few imported) pianos. If they don’t have the original scale they fake it by using one that is similar. At least that has been their past practice. It may have changed in the past several years. We purchase all of our steel wire from them but we no longer use their bass strings.

Del

So I've heard.

When I started to investigate the soundboard and its function one of the first things I was told was that soundboard performance was difficult to predict. And now one really knew why. This was almost regarded as the holy grail of the piano business. The more I learned, however, the more I found that only certain types of soundboard systems are unpredictable; those that are purely compression-crowned. That is, those that depend entirely on the internal, perpendicular-to-grain expansion and compression of the wood grain to form and hold crown. Others, specifically those that depend on curved ribs for their crown, are both more predictable and longer-lived.

There are rebuilding shops using both methods. Those using compression-crowning techniques maintain tight controls over their process and produce work that is at least as consistent as that of the manufacturers still using compression-crowned soundboard systems. (At least those that I am familiar with do.) Those shops using rib-crowning techniques (and we are among them) also maintain tight control over the whole process. It is a bit easier to predict results because we do not depend quite so much on the variable qualities of wood.

I suppose if one is working with a shop that is installing its first soundboard assembly — assuming the person in charge has not bothered to take advantage of the vast amount of training and information now available — the results might be unpredictable. But, of course, the same thing could be said of a shop installing its first set of hammers or wippens. Or doing its first restringing job. Or to the tuner doing his or her first tuning or voicing job.

Del

I was not asking about replacing soundboards per se. I was asking about people who can redesign and replace soundboards. It sounds like your shop could well be the only one in the US that can redesign a soundboard, Del.

Ah, well...I don't really know. I'd like to think there are at least a few out there. If for no other reason than I've been teaching this stuff for a fair number of years now. I hope it's not all gone to waste.

Del