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A true professed expert would also remain a true student. They are not mutually exclusive. It is a distortion of logic to posit like that. Reminds me of the simpletons who make a fabulous living as talking heads on the media with all their "balanced and fair" pablum.

I must admit it has proven to be a successful business plan. One must never overestimate the intelligence of a group of people who decide believing in a "truth" is more important than knowing what truth is or isn't.

The contradictions are endless
From this:
"I do have much experience with the problems with compression crowned boards and if you re-read my posts, my criticisms are based on that process".

To this?
"I am however interested in flat sawn rib designs coupled with a compression designed board and could stand to be enlightened"

Thats a figment? Okay whatever.

Regarding the two type of systems, I just don't think you can approach a floor joist and a vibrating membrane in the same way. Some of my students came over today and we were discussing what changes I would make to The 7' tall upright I built 10 years ago. At the time, i semi relied on Wolfenden and an article from the journal on selecting rib dimensions. In hindsight, the rib scale is not to my liking, and making a few changes in the piano is possible. Pretty cool stuff. A few special thumb planes perhaps for the tight quarters.
-chris

Well, could you make a recording, before and after, so we can hear also. "for learning" maybe.

And most importantly! why you are going to do these changes.

Oh and you never fail to mention how the original materials are no good.
That is denial big time.
It is not insulting, It is ignorant.

Maybe your big upright will sound good after the adjustment.

R. Blais.

Thank you for the questions,
I don't know how a recording can capture the experience of what a piano sounds like at the keyboard and simultaneously its projection across the room. Projection seems to be the big gain with the principles and experiments i have discussed. There is a certain piano sound that i like, and when I came across a few of those rare birds, I tore them apart and worked backwards into the design to determine the distinguishing characteristics.

I will refer you to this article of ignorance regarding material science.
https://en.wikipedia.org/wiki/Fatigue_(material)

Also, there are plenty of videos in which blind tests of comparison clearly show that old aged wood has no perceived tonal advantages over new wood among professional musicians who have cultured ears.

With new wood there is a bit of control between tree - kiln - shop. When you add a hundred years of unknown variables to that equation, it at the very least becomes riskier to use..

The big piano sounds fantastic now I assure you. i plan on having pianists make professional recordings on it once my showroom is finished.
But that's another story.

-chris

Chris
My experience with compression crowned boards is limited to working with a functional piano that has one, trying to get it to sound good, compensating for flaws in the board by voicing, adding riblets, adding weights etc etc etc and maybe replacing them with my idea of a more controllable system. iv never designed and built and installed a compression board. It don’t take much thinking to figure out that being curious about the ribbing of one of these is desirable.
And your without contradiction I suppose, an authority on clear thinking?

Gene,
Fair enough.
Regarding the ribbing in compression boards here are some things I found. First, there are no two rib scales alike. Even on the same model. The lengths don't coincide with the volumes. Which is quite odd. You would think that the longest rib would also be the largest rib. Some rib scales vary in dimensions, and some don't. Some have low rib counts, others have excessive rib counts. You also see a lot of copying from one manufacturer to another. I recently found a Baldwin that copied a Steinway Rib scale but altered two ribs in the treble section. I presume to address the killer octave problem. Out of 200 scales in my database only 2 appeared to be engineered. At the very least, if controlling stiffness is important, the scales would look very different than they do. So just like string scales that are riddled with errors and can be smoothed out, so its the same with rib scales. I have observed that when I smooth out a rib scale, and proportion the volume to match the length curve, use the correct rib count, riblets are totally unneccessary.
-chris

Thank you.

We read the metal fatigue thing? Has zero application for understanding wood.
Steel isn't hygroscopic, and does not change with age, only temperature.

Which two scales were the ones seemingly correct, or is that proprietary info?
Amazing how no one asks me any questions ever.

R.Blais.

All the problems with SB construction now days is because the material "wood" is not properly prepared before,"SEASONING"
One ca him-haw and deny, and call it hogwash, and there seem to be no shortage of naysayers! who insists that aged wood is not as good. Isn't it ignorance to not want to learn.
R.Blais.

Any soundboard design that doesn't take into account compression set has not been completely thought through. Compression set is a very real phenomenon in wood, and has been understood, documented, and recognized for many decades. In a soundboard design, it can be the limiting factor in terms of expected performance over time. BTW, this is a general comment and is not aimed at any particular poster(s).

On the contrary compression set has been completely thought out. As Ed McM stated, the soundboard is an expansion joint. And just because a compression soundboard uses compression as a means to develop stiffness, does not mean it has suffered from compression set. That's a big assumption on your part. Here's your hurdles for burden of proof: 1) you have to know on every board that has failed what the installation moisture content was, 2) then you have to know what Humidity cycles it went through in order to claim compression set was the cause. I have seen Zero data that states the installation MC, and then plotted the life of a piano that went through high humidity swings and document the resultant damage.
I propose that the most likely scenario is a high MC install and the piano living in dry conditions as the most likely cause of cracked boards. And also as stated by ED, the RC&S boards with their minimal expansion joints, have a higher likelihood of being the horribly cracked boards of the future.
-chris

About 1 1/2 years ago, I visited Craig Hair's shop with my New Hampshire Chapter of PTG (if memory serves me, I believe Peter Grey was there). We saw how he does things and then listened to a rebuilt broad bellied 6'4 " Chickering. To bend a phrase, "I believed my lying ears....". It had a big and vigorous sound, strong from bottom to top (imagine that, a Chickering with volume and sustain in the treble). It had everything that a healthy soundboard has.

I also believe that such a thing as compression set exists in old soundboards.

So what gives in this seeming contradiction?

I think the answer is likely twofold. One, there is likely far less lumber in a panel that has compression set. How much, I cannot say. I doubt anyone else can say either. My sense is that it is likely far less of an issue than we believe.

Craig and I both live in Northern New England, a famously harsh environment for pianos. All those decades of these boards yo-yoing through large humidity swings take their toll and boards flatten out, lose compression and stiffness. We get that tired old board.

So someone like Craig removes the board non-destructively, removes the ribs and bridges, makes repairs to the panel, and then re-ribs the board via compression crowning using either new ribs or the original ones. And gets a very successful result by any standard. That is the second and perhaps most important part.

When you consider the sorry state of our forests these days, with lumber of ever poorer quality and less of it, something has to give. Craig works on many pianos that are old enough to have used old growth lumber from very large and mature trees. There is almost none of that lumber left for modern makers and rebuilders to use. If such lumber already exists in the piano that you have and is viable, why not re-purpose it? And why take more from an already scarce resource when we have other alternatives?. Craig has spent a couple of decades honing his methods.

Could it just be that Craig and Richard Blaisdell are in the vanguard, looking at the rest of us in the rear view mirror?.

That day, listening to their pianos, I thought that maybe my world is a little bigger place than I had thought. That's nice to know.

- Will Truitt

Craig,
Just because wood is Hygroscopic doesn't mean its immune to fatigue.

I'll amend that a little, I found 3 Rib scales that look engineered A 7'4" Weber and a 7' Decker brothers from the 1890's. And a Charles Stieff Upright 1905. All of them went to a low Height profile and the volumes matched the length curves and were proportioned with thought and accuracy. I also had come across a second Stieff upright that was not. I later discoved that One was made by the superintendent/designer Jacob Gross and the other was after he was gone.

When you talk about wood seasoning, are you talking about the resin content??

-chris

Hello Will, we have never put in new ribs
.
Chris,The resin is still there, It is oxidation of resin and it takes time, years, with atmospheric pressure variances.
The wood breathes in and out high pressure, low pressure, over and over, with every storm, carries in "oxygen". slowly, too slow for most!, soft wood is faster than hard maple. that takes ten years, anyway?
Imagine trying to keep thousands of board feet of lumber, for years, not here! they come around and tax your inventory on the value, every year. Violin makers have to hide the wood. It is too bad.

Roy, I never said there is no compression distortion "set", but I never found crushed cells, and if you do, let me know, I would like to see them. Darn it! seasoning is were the engineering you talk about began, once upon a time, right after cutting.
On with the chase!
R.Blais.

Just curious, but who is "R Blais", as distinct from Craig Hair? It's a bit confusing because I always thought we were talking to Craig.

I am his business partner. 32 years.
You must not be paying attention because I sign my name every time, for years.
R. Blais.

OK, For those who care, Google this. Properties of aged tone wood japan studies. There is some info there.
R.Blais.

Several years ago, I was fortunate to have 3 Bush and Gertz uprights. The exact model.
In one, I put a Sitka Spruce soundboard with Sitka Spruce ribs.
The second, I put Red Cedar with Sitka Spruce ribs from NW Specialty Woods.
The third, I put Douglas Fir with Douglas Fir ribs.
Ronsen Hammers in all three. Mapes bass strings in all three.

The Spruce BG sounded as expected. The Cedar BG sounded more open. The Douglas Fir BG sounded tighter. All three sounded excellent, and unless told, no one would guess the different species. These were just subtle changes in timbre.
If I had a choice, I would personally lean towards using cedar for soundboards over Spruce because I liked the sound it produced. The only problem would be public acceptance. But tonally, its fantastic imo.
The common denominator is that all three were professionally installed. If any one of them were poorly installed, the result would be poor.

-chris

Soundboard failure due to compression set is well documented. You don't have to look for crushed cells. Obviously, a number of factors determine the likelihood of compression-set failure in a particular soundboard design, but to deny its existence is to deny reality. Anyone can search and read about what percentage of cross-grain compression will lead to failure. BTW, I did investigate the link referenced by Craig Hair. Here is a quote from the referenced study,
"Although aged wood appeared more rigid and stronger than recent wood, after density and humidity corrections were applied no significant variation of L and R rigidity or L strength was observed. The post-linear behaviour, however, was drastically influenced by wood age especially in R direction where the strength and rupture energy decreased markedly with the time elapsed since the wood was processed. Well-preserved aged wood can be considered as safe as long as it is not loaded perpendicular to grain. "
The study specifically recommends NOT using old wood where it will be subject to cross-grain loading. Hmmmmm.

This snide response is not a good reflection on you.