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BDB,

Thanks for your reply. If I recall correctly the idea is not so much to "make it softer" but rather to not heat it so much it reaches the point of brittleness. That is, bring it to the right hardness as opposed to maximum hardness. But if you are saying the goal is to make the bearing surface softer than the metal underneath the surface I would wonder what the point would be of that.

I wish I could recall the technique that specifically applies to pianos. It's only the surface of the bearing that one would be concerned with, not the bulk of the metal mass.

Also if I recall correctly, you do not think that old soundboards that otherwise look good need replacing. Correct me if I'm wrong in quoting you.

I would assume then that you do encounter old rebuilt pianos with these sustain problems. I know I have seen many (though granted I can't say I've known any specifically that have always lived on the West Coast). I am curious as to what you find can be done to correct this problem, if it's not the board. (Apart from the obvious like loose bridge pins, loose plate bolts, etc.)

When you personally restring pianos, do you find that none fail in the treble sustain department? If so, what do you think you are doing that other restringers may be failing at?

Regards,

Rick Clark

I think you are referring to case hardening. That is a method of hardening the surface of low-grade steel and cast iron. I don't remember the exact process, but I think it involves heating the area while it is covered with a carbon compound, so that the carbon enters the metal and hardens the surface. It would probably be about as easy to machine a groove in the v-bar and put a length of thick music wire in it.

As for sustain problems in old pianos, I think that most of them stem from old strings, plain and simple. The composition and crystal structure of alloys changes over time, and markedly affects their sound. While bass strings get tubby, treble strings get crystaline and tinkly. They become thin, harsh and less flexible, which gives them less sustain.

I think you can accellerate the aging process of strings by the usual processes of stretching, something I am firmly against. I never like to take a piano string much above pitch, or to press on the strings.

I also think sloppy worksmanship of any sort is more detrimental than people realize. Also, old hammer have a detrimental effect on sustain. But in short, there are many more ways to do a job wrong than to do it right.

But the question of sustain is tricky. It's hard to measure. One would have to measure it by some regular method, surer than just listening with a stopwatch. So many things change just with hammers and strings that we can't rely on just our senses. To do a real comparison of the difference in the sustain between a new soundboard and an old one, you would need to restring a piano and measure it, then tear it apart, replace the soundboard to the standards of the original, and restring it again to the same standards, and then measure it again. That's an expensive process. Do you know anyone who has done it?

A loose end: I've mentioned that alloys change over time. Wood does too, but not as much, since wood is mostly empty air space. I'm not certain that wood is not better for soundboards when it gets older, rather than worse.

I'm not even certain how important such things as crown and downbearing are. I think an absolutely flat soundboard is bad, but it may not take much to make it less than flat. Downbearing is very small compared to sidebearing, provided by the offset of the bridge pins, and additional downbearing is added by the combination of the sidebearing and the slant of the bridge pins, which in combination, tends to wedge the string against the bridge.

BDB,

Thanks again for your thoughts.

For the pianos I am referring to with a lack of sustain in the upper octves, you can take old strings out of the formula. Of course old strings can have a really negative impact on tone, I wouldn't base my judgements on those. The piano I mentioned previously in this thread has practically new strings.

I am referring to restrung/restored pianos with relatively new strings. And since the lack of sustain is evident even when plucking the strings, it's not the hammers.

And while there is no agreed upon standard for measuring sustain, what I am talking about is plain to hear. Any tuner/tech would know that something is "wrong" when plucking the strings in the top 2 octaves.

If there were to be a standard, I would advocate a DT60 standard- or the amount of time it takes for the volume to decay 60 dB (discounting the first few ms/initial attack volume spike).

Regards,

Rick Clark

As I said over the tech area, there isn't much sustain in the top two octaves, even on a new piano. That's why there are no dampers there. Also, there is less volume there to begin with, so it may be difficult to measure in this society of high ambient noise.

It is very easy to screw up that area of a piano. Some of it is done in the design phase, in fact. Old habits die hard, and while it is common practice to change gauges pretty often in the high treble, and less often in the midrange and lower tenor, for most pianos, exactly the opposite would provide a smoother range of tensions. Oddly enough, it would be cheaper, too, since you would use more of the cheaper (by length) small gauges, and less of the more expensive large gauges.

I do get a chance to compare from time to time. This week it was two Bechsteins, an E and a C, about 60 years apart. They sounded remarkably similar, despite the intervening design changes. There are a couple of Bösendorfers, same model, 40 years apart that I've seen very close to each other. I think the older one is a bit richer sounding. All original soundboards. The strings on the Bechsteins are probably about the same dates, the older Bösendorfer's strings are about a decade newer.

Anything that affects either the stiffness or the mass of the soundboard system will affect the brightness and/or warmth of tone to some extent. Crown (and the subsequent loading of the strings bearing against the bridges) has a significant affect on the stiffness of the soundboard assembly. The loss of crown will reduce the design stiffness of the soundboard system causing it to accept energy more readily. Hence the tone will become somewhat more percussive in nature and will have a corresponding reduction in tone sustain.

In general, however, the overall balance of tone color is more dependent on a number of design elements including the overall string tension scheme, the design stiffness and mass of the soundboard assembly, the mobility of the bridge as determined by the backscale, etc. Some of these interactions have been discussed in this forum in the fairly recent past.

Del

You can find the same phenomena in brand new pianos. A year or so back I looked at three new seven-foot pianos of the same make and model still on the showroom floor. Each had significantly different sustain qualities. While the differences were most notable in the fifth and sixth octaves, they could be easily detected throughout the compass of the three pianos. Comparing the “best” of the three with the “worst” of the three yielded a sustain time (compared on a note-to-note basis) of about 2:1 through the middle of the so-called “killer-octave” region.

Since these were all new pianos I think we can safely rule out significant differences in the string scales (including the age and quality of the strings), the plate metallurgy, etc. We can also rule out the hammers since the differences were clearly apparent with plucking. The remaining significant variable being the soundboard assemblies.

Del

Thank you, Del.

Del - I always enjoy your posts.

Many thanks,
Steve Ries

Other variables that might have a bearing would be the metallurgy and heat treatment of the strings, the method of stringing, and the chipping and first tunings.

If there is such a difference even in the same make and model of piano, then that means that the variability is beyond the those which could be attributed to design and construction of the soundboard. After all, they all would have had the same design and construction.

Perhaps the most important thing that comparisons like this show is that most people don't care enough about the sustain of the tone, at least not enough to demand that it be consistent.

Del & All,

I have seen some new Chinese pianos that arrived from the factory 25-35 cents sharp. (However from the same factory others arrived flat, or approx on-pitch.)

A tech will of course realize that it must have been set quite a bit sharper than that before it fell down to +30.

I was really quite concerned if this overtensioning practice was going to have the effect of killing string tone/elasticity or perhaps other deadening effects. Unfortunately circumstances were not such that I could follow the future progress of the pianos.

Del I am curious if the new pianos you are mentioning were Chinese product that may have been overtensioned as described above.

Regards,

Rick Clark

Del, I am curious as to the actual brand of the piano. I don't think you have written anything here that would offend a manufacturer.

1] The quality and consistency of Mapes IG wire is exceptionally good. The strings would receive no heat treatment other than that of the very carefully controlled factory processes. Chipping and first tunings should be fairly consistent within a given manufacturers process. Unless this is done horribly wrong it will have little, if any effect on the tone performance of the piano.

2] The primary difference in this case is the soundboard assembly and how the individual soundboards have responded to essentially identical climate exposure.

3] What can I say. When I visited the same showroom some months after my initial examination two of the three pianos were gone. Guess which one remained.

Del

No, they were not Chinese. They were made in the good old U.S.A.

Del

It certainly should.

Del

In NYC I bet. Compression crowning will give that amount of variability, I've heard

"“Violence is the last resort of the incompetent.” Isaac Asimov"

Indeed.

Dan

Well, Del said 7', mapes wire, and made in USA, so that could be M&H, or Steinway. I usually have 5 new BBs set up side by side, and while they do differ a bit in sustain, I have not noted anywhere near the discrepencies Del noted, so I have to assume you are right Dan.

It might have been the Baldwin SF that Del is hinting at.

So if there is one bad sample out of three which did not sell, and it wasn't caught by QC at the factory, either it was damaged in transportation, possibly for climatic reasons, or it was not deemed defective by the manufacturer. In any case, it seems it wasn't thought defective by the dealer.

I actually do doubt that there was a problem manufacturing the wire. After all, that would likely only affect one size, and as I said, everybody changes gauges much too often in the treble.

Defects in design shouldn't result in sample defects. If there was a defect in worksmanship, it is as likely be with the stringing as the belly work. Damage in shipping seems most likely, but it's a mystery to me.

Three new Baldwin SF-10s in one showroom? Where?

When the problem of abnormally short sustain shows up in a piano that is known to be capable of good sustain the cause is nearly always traceable to changes taking place within the soundboard assembly. Like it or not, wood under constant strain does undergo physical changes. Especially when that stress is predominately compression perpendicular-to-grain. Compression set is a fact of life and can be ignored or dismissed only at our peril.

This is a phenomena that still seems to be poorly understood within our industry even though the wood technology governing it has been well understood and quantified for decades.

As to whether this is a design issue, a construction issue or a materials issue is moot. The three are tightly interrelated. Personally, I am skeptical of any design feature that regularly places any material at levels of stress and/or strain at levels beyond its physical capacity. Unless, of course, you are preparing a car for the Indy 500 and expect it to fall apart after 500 miles.

Del