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Re: Laminated soundboards [Re: acortot] #2465264
09/30/15 11:11 PM
09/30/15 11:11 PM
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Originally Posted by acortot
one thing that Laminated Soundboards could do to improve the lightness to stiffness ratio could be to substitute the middle section with a lighter and more porous wood.

I had a set of 3-ply drums which had the middle layer made of a softwood with hardwood veneer.. sounded good.

I mean, if you use hardwood on the outside and then a very light wood in the centre, you would get the stiffness but lightness as well.

might sound awful but maybe it wouldn't.. say in the bass section.

There are many possible variations that could be used. But we are back to the marketing challenges. Many piano salespeople already misrepresent the qualities of all-spruce laminated soundboard panels. It frightens me to consider what would be said about a laminated soundboard panel using padauk faces on a balsa core.

I don’t want to fight that battle until we’ve made some progress on this one.

ddf


Delwin D Fandrich
Piano Research, Design & Manufacturing Consultant
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Re: Laminated soundboards [Re: Dave B] #2465265
09/30/15 11:16 PM
09/30/15 11:16 PM
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Originally Posted by Dave B
Del, Thanks for the article. You've addressed many of the issues I've been wondering about. The one big question still remaining is life expectancy? Traditional spruce boards are, in my opinion, shot by the time they are 50 yrs old. Has anyone been able to do any testing of the effects caused by the woods natural deterioration?

Who knows? Laminated soundboard panels are not subjected to the same damaging stresses common to solid panels. Given that I would expect an indefinite lifespan. That is, the piano may well wear out are expire for other reasons but the soundboard itself should be fairly stable.

ddf


Delwin D Fandrich
Piano Research, Design & Manufacturing Consultant
ddfandrich@gmail.com
(To contact me privately please use this e-mail address.)

Stupidity is a rare condition, ignorance is a common choice. --Anon
Re: Laminated soundboards [Re: Del] #2465285
10/01/15 01:31 AM
10/01/15 01:31 AM
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Thanks very much Mr. Fandrich for your explanations above -

I went back to previous thread and it looks like I confounded who had what positions with respect to moisture barrier properties of adhesives. You clarified your understanding above as well.

On the other hand, I understand the reasoning behind the effects of grain angles, or at least I think I do. Modulus of elasticity and yield strength of wood is relatively much higher in the axial(longitudinal) direction, such that the thinner surface veneer at an angle to the thicker core can sufficiently constrain expansion of the core in the all-sensitive radial and tangential directions with increased humidity, the extent which will vary with that angle.

You wrote:

Originally Posted by Del
"Many piano makers specify a somewhat higher ambient moisture content (compared to solid spruce construction) when their panels are glued up so they start out much closer to the average moisture content found in typical homes than is common with solid wood panels. This reduces the compression peaks without introducing excessive tensile stresses."


Sorry, I don't understand the key point here. Of course a compression crown board comes out of the board-making process, well, compressed and that much closer to incurring compression peaks,
And that's why some favor rib crowning, of course. but…

There would be no question that laminates display less macro cracks then boards. That's what glued laminates do, plywood, etc. I can understand why the piano market channels would prefer that, reduced warranty costs, etc.

[edit:I can also understand that thinner layers of pretty much anything are less likely to have a macro crack nucleate for a given stress, such as is the case for the thinner veneer surfaces, maybe not applicable to the core though.]

If it is claimed it has better tuning stability, then the board core is being constrained . Said simply though, my general understanding of things makes me say, a more constrained system will experience more stress, and higher stress generally speaking, leads to more damage, somewhere. My thinking would be that since macro cracks are prevented from opening by the laminate, it might instead be on the micro scale.

If I were reading my above paragraph objectively, I might say, that guy is setting up the perfect conspiracy theory explaining that the bad stuff happens where you can't see it. But again, generally, a more constrained system should experience relatively more stress with the humidity changes, I think. So that might need a simple explanation showing that isn't the case here.

Originally Posted by Del
Piano manufacturers routinely tear laminated soundboard panels apart to verify that their suppliers are giving them panels that meet their specifications.


So they are outsourcing their boards? Interesting.

Thanks again-

Last edited by phacke; 10/01/15 02:08 AM.

phacke

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Re: Laminated soundboards [Re: Del] #2465364
10/01/15 10:08 AM
10/01/15 10:08 AM
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Maryland/DC/No. VA
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Originally Posted by Del
But we are back to the marketing challenges. Many piano salespeople already misrepresent the qualities of all-spruce laminated soundboard panels. It frightens me to consider what would be said about a laminated soundboard panel using padauk faces on a balsa core.

I don’t want to fight that battle until we’ve made some progress on this one.


The marketing issues surrounding laminated soundboards are very challenging and we here on PW can help.

Consider a novice shopper in a town with two dealerships. Dealer A carries the Kaiserway line with a high-tech laminated soundboard which the dealer extols through the virtues that Del has pointed out. The piano sounds good to the shopper, but being uneducated in piano tone, they aren't "attached" to performance.

They go to Dealer B who carries the competitively priced Henway, entry-level piano with a low-grade solid spruce soundboard. They point out that out the of the top 25 brands of pianos on the market none use a laminated board. And, every single one of these "top 25" uses a solid spruce board, "just like our Henway". It is a compelling argument.

As pianos with these high-tech boards hit the market and novices inquire about them here on PW, we need to help make the case for considering them.



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Re: Laminated soundboards [Re: Del] #2465432
10/01/15 02:34 PM
10/01/15 02:34 PM
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Steve's among post underlines an ongoing dilemna in the industry.

That's why IMHO salespeople carry an additional burden to explain things right.
Something that is not always happening.

Quote
The piano sounds good to the shopper, but being uneducated in piano tone, they aren't "attached" to performance.


Another point why education of the 'honest type' is so very important.Wondering how many times the 'Volkswagen story' would repeat itself if things would come out later...

At same time it's become fact that even as player it is becoming increasingly difficult to tell exactly which is which.

Which, IMHO is good for consumers.

Today there are many great sounding pianos on the market using laminate i.e. "all spruce" soundboards. A term often used to not tell the whole story or even deceive.

Ritmuller, as many other makes, has laminates among it's lower rated series, something we carefully point out to every single customer. The nice thing not everybody is noticing or caring about this. As Del pointed out, there are also some advantages.

Of course "all spruce" pianos are always cheaper - another good thing. So why not earn one's business being forthright and open about things?

Wishing that everybody else would be doing same.

Listening in and careful exploring a piano's sound potential is still where it's all at. IMHO

It's similar like good food: one's it tastes great one needs spending little time to explore exactly "why".

Nor would one have the need to move on to another restaurant in the hope of "getting still better".

Norbert wink

Last edited by Norbert; 10/01/15 02:46 PM.

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Re: Laminated soundboards [Re: phacke] #2465435
10/01/15 02:49 PM
10/01/15 02:49 PM
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Originally Posted by phacke
… On the other hand, I understand the reasoning behind the effects of grain angles, or at least I think I do. Modulus of elasticity and yield strength of wood is relatively much higher in the axial (longitudinal) direction, such that the thinner surface veneer at an angle to the thicker core can sufficiently constrain expansion of the core in the all-sensitive radial and tangential directions with increased humidity, the extent which will vary with that angle.

You wrote:

Originally Posted by Del
"Many piano makers specify a somewhat higher ambient moisture content (compared to solid spruce construction) when their panels are glued up so they start out much closer to the average moisture content found in typical homes than is common with solid wood panels. This reduces the compression peaks without introducing excessive tensile stresses."


Sorry, I don't understand the key point here. Of course a compression crown board comes out of the board-making process, well, compressed and that much closer to incurring compression peaks,
And that's why some favor rib crowning, of course. but…

There would be no question that laminates display less macro cracks then boards. That's what glued laminates do, plywood, etc. I can understand why the piano market channels would prefer that, reduced warranty costs, etc.

[edit:I can also understand that thinner layers of pretty much anything are less likely to have a macro crack nucleate for a given stress, such as is the case for the thinner veneer surfaces, maybe not applicable to the core though.]

If it is claimed it has better tuning stability, then the board core is being constrained. Said simply though, my general understanding of things makes me say, a more constrained system will experience more stress, and higher stress generally speaking, leads to more damage, somewhere. My thinking would be that since macro cracks are prevented from opening by the laminate, it might instead be on the micro scale.

If I were reading my above paragraph objectively, I might say, that guy is setting up the perfect conspiracy theory explaining that the bad stuff happens where you can't see it. But again, generally, a more constrained system should experience relatively more stress with the humidity changes, I think. So that might need a simple explanation showing that isn't the case here.

I’m not quite sure I get either the point or the question but I'll take a shot at this and see what happens.

All soundboard panels are subject to stress. If you think about it, what is the conventional solid spruce panel/rib configuration but a constrained two-ply laminate. The solid spruce panel is still subject to perpendicular-to-grain compression and tension even though there is no cross ply surface veneer.

Wood is moderately compliant—spruce can handle up to about 1% perpendicular-to-grain compression and about 0.5% stretch without exhibiting physical damage. If you start with wood that is very dry—say, 4%—and constrain that piece of wood in the perpendicular-to-grain direction and move it to an atmosphere that raises the moisture content to 18% you’re going to exceed that limit. If you hold it there for any length of time you’re going to have a problem. If you start at 6.5% or 7% and raise it to the same 18% moisture content you will have considerably less perpendicular-to-grain compressive stress and you might get by with it. At least you’ll get by with it longer.

But I’m not sure if this really matters in laminated soundboard construction. Essentially what we have is a thin piece of lumber-core plywood. This is the stuff upright case parts and grand lids and other flat parts were made of for a hundred-plus years before MDF came along. Longer than that in other woodworking endeavors. Even while the solid spruce soundboards inside these pianos were self-destructing their lids were doing just fine. Were there macro- or micro-cracks developing in the (usually poplar) core material? I have no idea; I’ve never seen any signs of them but I’ve never examined any of this wood through a microscope either.

The core panel in a laminated soundboard panel is also constrained. Do macro- or micro-cracks develop in this wood? Again, I have no idea. They might but I’ve never seen any evidence of such. As with the above-mentioned lumber-core plywood, though, I’ve not examined any of them through a microscope. Some damage might well be there—if I get the chance someday I’ll look—but even if I do detect some such, my question then becomes: so what?

There are hundreds of thousands of pianos in service with laminated soundboard panels in them. Their track record for both stability and durability is excellent. There is an occasional—very occasional—report of one of these panels delaminating. This is usually, if not always, traced to an undetected poor glue spread during manufacture. I’ve never heard of a failure that could be traced to either macro- or micro-cracks in either the core or face veneers.

So, while your question is intellectually interesting I can see it having any particular relevance in the real piano world. That said, if I’ve missed your point we can try again.


Quote
Originally Posted by Del
Piano manufacturers routinely tear laminated soundboard panels apart to verify that their suppliers are giving them panels that meet their specifications.


So they are outsourcing their boards? Interesting.

Some do, others make them in-house. In either case a manufacture with a functioning quality control department will be testing critical components—including laminated soundboard panels—to verify that they conform to design and quality standards.

ddf

Last edited by Del; 10/01/15 02:57 PM.

Delwin D Fandrich
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ddfandrich@gmail.com
(To contact me privately please use this e-mail address.)

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Re: Laminated soundboards [Re: Del] #2465453
10/01/15 04:11 PM
10/01/15 04:11 PM
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Originally Posted by Del
Using epoxy would slow the process and drive up the cost considerably. I'm not sure just what, if any, benefit would be derived with this. I can think of some potential theoretical advantages but I rather suspect they would be just than -- theoretical.


It might be worth trying some prototypes. If there is an advantage, then work on increasing the efficiency/reducing the cost. Perhaps there's something to be learned from the fiberglass boat builders....



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Re: Laminated soundboards [Re: Del] #2465460
10/01/15 04:22 PM
10/01/15 04:22 PM
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The long and short of this is that laminates are cheaper to make, offering the public some viable, very acceptable alternatives to solids.
People should perhaps check the specs of their own pianos [if made available by company..] - many would perhaps be amazed....
If willing to pay more, most of the discussion is mute.
Good laminates, i.e. "all spruce" soundboards can and often 'are' a great alternative.
But it would be nice if the industry [including store salesmen..] would be totally honest about this issue.
It's was one of the reasons why we dropped an entire line before. They started out right but then changed midstream.
Nothing to hide, really....

Norbert smile

Last edited by Norbert; 10/01/15 04:25 PM.

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Re: Laminated soundboards [Re: Del] #2465572
10/02/15 01:36 AM
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Greetings again, Mr. Fandrich
Thanks so much for taking the time to explain so that I can understand your thinking about the matter.

Quote
I’m not quite sure I get either the point or the question but I'll take a shot at this and see what happens.


My read is you have the jist of of, but, specifically, I was asking for comment on this issue I wrote of:
Quote
If it is claimed it has better tuning stability, then the board core is being constrained..., a more constrained system will experience more stress, and higher stress generally speaking, leads to more damage, somewhere.


So the literal questions are: Is this true or not? If not, why is this system special or what am I missing?

In more dramatic terms, if we are moving from freezing ice in a rubber container to a ceramic container (the more constrained system), the stresses will be actually higher and something may give, the ice will fissure or the ceramic container will fracture so that stress is relieved.

The mechanism is clear that on axis grains of the laminate are constraining the core, and to the extent one says that tuning stability is improved, I am saying that stresses in that system will be actually higher than in the conventional board, and if a conventional board yields or fatigues, then the laminate system will too, and if the stresses are higher, then moreso.

You of course have many observations you wrote of, and probably more that you have not discussed, but I can address my concerns with respect to what your wrote of here.

Quote
All soundboard panels are subject to stress. If you think about it, what is the conventional solid spruce panel/rib configuration but a constrained two-ply laminate. The solid spruce panel is still subject to perpendicular-to-grain compression and tension even though there is no cross ply surface veneer.


In a round about way, this example can be an illustration supportive of my point. In humid conditions, conventional boards fail at the rib/board interface in no small part, I think, because of the various mismatches at that interface. Of couse, what the adhesives are doing matters too in this mix. Specifically for humid conditions, Steinway screws the ribs on to deal with this, to an extent. Of course we need to be quantitative about this, and we do, below.

Quote
Wood is moderately compliant—spruce can handle up to about 1% perpendicular-to-grain compression and about 0.5% stretch without exhibiting physical damage. If you start with wood that is very dry—say, 4%—and constrain that piece of wood in the perpendicular-to-grain direction and move it to an atmosphere that raises the moisture content to 18% you’re going to exceed that limit. If you hold it there for any length of time you’re going to have a problem. If you start at 6.5% or 7% and raise it to the same 18% moisture content you will have considerably less perpendicular-to-grain compressive stress and you might get by with it. At least you’ll get by with it longer.


I have seen quite clear data on this too, for example, HERE

See p 471, the figure on bottom right.

The solid diagonal line indicates the stress free interface state for various starting relative humidity (RH), such as I suppose would be found at the center region of a rib crown board. If humidity goes up the board expands, constrained by the rib, it goes into compression. Depending on what your staring humidity was, you can see by the upper data points and line that yield happens with a 10% to 30% RH swing to the upside. That graph is showing yield for perfectly constrained tangential wood (and I assume the axial dimension of the of the rib is nearly a perfect constrainer in its longitudinal/length direction), but let's face it, even the highest quality boards are rarely perfectly quarter-sawn, and sorry, I have think it may be at times less perfectly so if it is laminated with a face veneer.

Now, if we are saying the laminated board moves less with humidity, it is more perfectly constrained, the stresses on the core are higher, so I'm saying this rational is telling me that the core in the laminated board is more likely to yield than the conventional board.

(Keep in mind too that materials, including wood, experience fatigue with cyclic stress at levels below their yield point)

Quote
But I’m not sure if this really matters in laminated soundboard construction. Essentially what we have is a thin piece of lumber-core plywood. This is the stuff upright case parts and grand lids and other flat parts were made of for a hundred-plus years before MDF came along. Longer than that in other woodworking endeavors. Even while the solid spruce soundboards inside these pianos were self-destructing their lids were doing just fine. Were there macro- or micro-cracks developing in the (usually poplar) core material? I have no idea; I’ve never seen any signs of them but I’ve never examined any of this wood through a microscope either.


I need to go on a little tangent here first before addressing this. This is a bit of a complaint about the ink that is spent on the fact that laminated boards don't crack.

A key point: cracking is not their particular failure mechanism.

So if we are looking for macro cracking as a metric, we are looking in the wrong place.

Back to your paragraph above. It might be a bit of a tangent, because mahogany is the veneer of choice which has very special properties as a rainforest wood, a wood of choice for high humidity applications, and the substrate and mounting protocol is different too.

That said, I observe checking, not lacquer checking, but veneer checking on old pianos. Checking is the failure mechanism of the thin wood laminates due to humidity cycling. The laminate soundboard has thicker top and bottom surfaces with more all-around strength. So yet again, the system is different.

Quote
The core panel in a laminated soundboard panel is also constrained. Do macro- or micro-cracks develop in this wood? Again, I have no idea. They might but I’ve never seen any evidence of such. As with the above-mentioned lumber-core plywood, though, I’ve not examined any of them through a microscope. Some damage might well be there—if I get the chance someday I’ll look—but even if I do detect some such, my question then becomes: so what?


I think we will all agree that it is the sound that matters over the time in the use environment. I have to think that collapsed wood cell structure is not a good thing, damps sound, etc, but I have not studied this matter.

Quote
There are hundreds of thousands of pianos in service with laminated soundboard panels in them.


Wow, that's a lot. where does this data come from?

Quote
So, while your question is intellectually interesting I can see it having any particular relevance in the real piano world. That said, if I’ve missed your point we can try again.


The thing is, if your read a book like "The Toyota Way" and read about double loop learning, you come away with the understanding that to have good quality results, one has to understand fundamentally what is going on. Yes, observables on old sound boards are good. experience as you have with changing the lamination angle is good. But to understand such things as, what are the tolerances? to understand the implications, before they happen, of controlled and uncontrolled changes in the process, the theoretical understanding is necessary too. When I see the conundrum, where the laminated board is potentially in a higher stress state, you know, I think it is a valid concern. I am not bringing up the effects of the phases of the moon here!

When we watched Japan come up, we thought they were doing nothing but copying without understanding.

Changes in attitude were driven in view of this, buy the US gov't no less.
In the time of pre mid-70’s: Only non-commercial true research was supported

then, mid-70’s: about-face to focus only on ‘applied’ science (misreading, and then 'thinking' they were emulating Japan)

USA across the board, started to make junk, with many quality problems.

Then, there was a drifting to realization in the late ‘80s that “you have to understand what it is you are doing”
The organizations that survive are the organizations that keep learning, fundamentally understanding. Actually, I think your are generally on to this, so all is good.

Spiel-off, thank you for listening, best regards,

Last edited by phacke; 10/02/15 02:08 AM.

phacke

Steinway YM (1933)
...Working on:
J. S. Bach, Toccata (G minor) BWV 915
(and trying not to forget the other stuff I know)
Re: Laminated soundboards [Re: phacke] #2465588
10/02/15 04:09 AM
10/02/15 04:09 AM
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Originally Posted by phacke
My read is you have the jist of of, but, specifically, I was asking for comment on this issue I wrote of:
Quote
If it is claimed it has better tuning stability, then the board core is being constrained..., a more constrained system will experience more stress, and higher stress generally speaking, leads to more damage, somewhere.

Not necessarily. If a beam is capable of supporting, say, a 100 lb load and you put a 10 lb load on it the beam will be stressed but not damaged.


Quote
So the literal questions are: Is this true or not? If not, why is this system special or what am I missing?

Well, a smoking gun would help. In other words it would help to find a few laminated soundboard panels that were exhibiting signs of stress failure. But, if such exist I’m not aware of them.

If the laminated soundboard panel is constructed with reasonable care it will be stressed at some times of the year but that does not necessarily mean it will be damaged. As noted earlier, spruce can withstand a certain amount of compression and tension without cellular failure. The core of laminated soundboard panels stay within this range. (Assuming the manufacturer has good and proper controls on moisture content.)

The acoustics of (some types of) solid spruce boards changes over time because the panel stiffness changes. True, this change takes place because of permanent compression—i.e., compression set—or damage to the wood cells but, by itself, it is not the cellular damage that causes the change in performance. It is the resulting loss of stiffness that that is the problem.

This does not happen with the laminated soundboard panel. At least not to any measurable degree. Soundboard systems using laminated panels—modern ones, at least—have some inherent amount of stiffness longitudinally to the aggregate grain angle. They will be somewhat less stiff perpendicular to the aggregate grain angle. (This is somewhat similar to the stiffness characteristics of a solid spruce panel before the ribs are glued on although its stiffness longitudinal-to-grain will be a little lower and its stiffness perpendicular-to-grain will be a little higher.) This panel is further stiffened by the attachment of (usually) crowned ribs underneath (or behind) the panel. It is an inherently stable system.


Quote
The mechanism is clear that on axis grains of the laminate are constraining the core, and to the extent one says that tuning stability is improved, I am saying that stresses in that system will be actually higher than in the conventional board, and if a conventional board yields or fatigues, then the laminate system will too, and if the stresses are higher, then moreso.

Not necessarily. It would depend on the moisture content starting point.


Quote
I need to go on a little tangent here first before addressing this. This is a bit of a complaint about the ink that is spent on the fact that laminated boards don't crack.

A key point: cracking is not their particular failure mechanism.

So if we are looking for macro cracking as a metric, we are looking in the wrong place.

Then what, pray tell, are we looking for? What, exactly, is their failure mechanism? Cracking longitudinal to the aggregate grain? I can’t see that happening. Cracking perpendicular to the aggregate grain? Here we’re into your macro- or micro-cracking but, again, my question is—so what? If such exists you’ll have to demonstrate—or explain—to me why it matters to the function of the soundboard panel.

Conceivably some cellular degradation could develop in the early wood of the core but, again I ask, so what? Exactly how is this going to affect the performance of the soundboard panel? What physical characteristic of the assembly is going to change? Are the ribs going to change? Conceivably the panel stiffness could change slightly but this would only be perpendicular to the aggregate grain angle of the panel.


Quote
I think we will all agree that it is the sound that matters over the time in the use environment. I have to think that collapsed wood cell structure is not a good thing, damps sound, etc, but I have not studied this matter.

I’ve seen no studies that support this view. But, like you, I’ve not studied the matter.


Quote
Quote
There are hundreds of thousands of pianos in service with laminated soundboard panels in them.


Wow, that's a lot. where does this data come from?

Consider that a company like Samick—one of the world’s larger piano makers—builds, perhaps, 10,000 pianos a year using laminated soundboard panels. (The actual count may be somewhat more or less but I doubt I’m far off. Over a ten year period that would be 100,000 from just one company. But Samick has been building pianos with laminated soundboard panels for several decades. Now factor in YC/Weber with similar figures. And Pearl River with considerably higher production numbers. And then add in the production numbers for all the other piano makers in Asia using laminated soundboard panels—Yamaha, Kawai, Parsons, Hailun, Pearl River, etc.—and then consider that most of these companies have also been making pianos with laminated soundboard panels for some decades. Several hundreds of thousands is a very low estimate.

In my article I focused on soundboards made by two companies—Samick and Hailun—both of which, while their designs differ, make soundboards of relatively high quality. It’s safe to say companies like Yamaha, Kawai, Parsons, Pearl River, etc. also make (or buy) laminated soundboard panels of relatively high quality. We would expect all of these to perform well over time. But there are other companies in China that make (or buy) laminated soundboard panels of rather dubious quality and even these have not developed reputations for structural failure.


Quote
The thing is, if your read a book like "The Toyota Way" and read about double loop learning, you come away with the understanding that to have good quality results, one has to understand fundamentally what is going on. Yes, observables on old sound boards are good. experience as you have with changing the lamination angle is good. But to understand such things as, what are the tolerances? to understand the implications, before they happen, of controlled and uncontrolled changes in the process, the theoretical understanding is necessary too. When I see the conundrum, where the laminated board is potentially in a higher stress state, you know, I think it is a valid concern. I am not bringing up the effects of the phases of the moon here!

Perhaps not. But I do think you are looking for problems where none exist. And please don’t assume that a lot of thought has not gone into understanding how these things work.

While you’ve introduced a lot of very detailed specifics about the behavior of wood, little of it has anything to do with how soundboards actually work. Inside a laminated soundboard panel, quite frankly, I don’t really care if macro- or micro-cracks were to develop in a perpendicular-to-grain direction. I’ve never seen any evidence that such cracks do develop but, even if they did, they would not affect the acoustical performance of the piano in any measurable or audible way.

I do not pretend to know all there is to know about laminated soundboard panels but I do know quite a lot. Some of this knowledge comes from my understanding of the nature and structure of wood, some my understanding of soundboards in general, and some from my work with developing and testing laminated soundboard panels since the 1980s. I admit that during that time I’ve not given a whole lot of thought to either macro- or micro-cracks developing in the softwood of the core material. Perhaps this is my intellectual failure but, since I’ve seen absolutely no evidence—none—ever—of structural or acoustical failure to these soundboard panels that could in any way be attributed to such internal damage, I’ve had little incentive to devote much time researching that specific aspect of their design. Perhaps I should but for the moment it is fairly far down on my list of priorities. (Unless, of course, someone comes along with a significant contract or grant to fund such a study—that would change things!)

The article I wrote for Pianobuyer was not intended to be an advanced technical dissertation on the subject. It was intended for a general audience made up primarily of people interested in buying an inexpensive piano that will serve their needs for a reasonable amount of time. Pianos using laminated soundboard panels have demonstrated over a period of decades that they can fulfil this need quite nicely. Their track record for both tuning stability and structural integrity are well-proven.

Is there more to learn? Of course there is but when I’m hired to develop a piano in the low- to mid-market range I’m going to recommend that it use a laminated soundboard panel and I’m going to design one that will both sound good and will last for the indefinite future and I'm not going to worry overly much about any potential cellular failure that can only be seen with a microscope that might someday show up. Maybe.

Sometime next year—God willing and the creek don’t rise—I plan to publish another, somewhat more technical, article on the subject in the Piano Technician’s Journal. Perhaps by then I’ll have learned more about them. I certainly hope so. But even there I doubt I’ll be spending much time investigating the possibility of minute cracks in the softwood layers of the core stock.

ddf


Delwin D Fandrich
Piano Research, Design & Manufacturing Consultant
ddfandrich@gmail.com
(To contact me privately please use this e-mail address.)

Stupidity is a rare condition, ignorance is a common choice. --Anon
Re: Laminated soundboards [Re: Del] #2465623
10/02/15 08:34 AM
10/02/15 08:34 AM
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Here are some common thinking about the tensionning inside the soundboard :

"Of course, the soundboard of a piano or grand piano as stress-free structure is already hard to imagine.

If the panel is not glued on completely within a very short time, then he must be well dried before gluing down.

The uptake of moisture then creates a compressive stress perpendicular to the grain.
And the base convexity is at least partially accomplished by tensioning the surface, and then, when the pressure bar rests on said bottom curvature oriented in all directions, produces a tension.
Nature and extent of the resulting tensions may be very different depending on the applied method .

In the conventional processes however it always results in a more or less uniform distribution of required tensions on the bottom surface but this is not used for the frequency adjustment.
There seems to be so far penetrated only slightly into the consciousness of the piano makers that what you see these tensions in the soundboard are not only static aspects or even as a method needed to preventing soundboard cracks, but they can also be used as a tool for sound design".

The few piano builders I talked with consider the curved ribs method qs inferior, the soundboard being "slow"

I wrote at Strunz and Ciresa asking if their panels are build that way or no, I will let you know their answer.

Besr regards


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Re: Laminated soundboards [Re: Del] #2465685
10/02/15 12:51 PM
10/02/15 12:51 PM
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I wonder if the positive attributes of laminated soundboards can also be applied to carbon-fiber composite soundboards.

Re: Laminated soundboards [Re: bleak] #2465710
10/02/15 03:19 PM
10/02/15 03:19 PM
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Originally Posted by bleak
I wonder if the positive attributes of laminated soundboards can also be applied to carbon-fiber composite soundboards.


I've watched carbon fiber composites try to gain traction in several musical instrument realms, mainly guitars and cellos. They never get past being a niche product. I think one of the reasons is that their harmonic envelope is just different and we like what we're used to. I liken it to LED light bulbs, the package says soft white and 5200 kelvin but it just doesn't look right. I do notice when I spend enough time in my music room which is all LED or daylight cfl's, when I go out to where the lighting is tungsten (about 5,000k) the light looks distinctly dingy and yellowish. I think if what we were used to was CF soundboards, that when we heard a wood board it would sound a little soft and muffled. We would miss the "clank" of the plastic.

I'll add that humans seem to have an affinity for wood that plastic just can't engender.



Kurt


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Re: Laminated soundboards [Re: KurtZ] #2465744
10/02/15 05:49 PM
10/02/15 05:49 PM
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Originally Posted by KurtZ
I liken it to LED light bulbs, the package says soft white and 5200 kelvin but it just doesn't look right. I do notice when I spend enough time in my music room which is all LED or daylight cfl's, when I go out to where the lighting is tungsten (about 5,000k) the light looks distinctly dingy and yellowish.


Actually, LED bulbs are typically much better than CFL's, though not as good as tungsten, for color. All flourescents are stuck with the strong mercury green line at 546.1 nm. You can use an old DVD or CD to diffract out the spectrum and see the mercury spike.

The dingy yellowish balance of daylight is because you're here where I am, in Los Angeles. It's the smog filtering the light.



-- J.S.

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Re: Laminated soundboards [Re: KurtZ] #2465772
10/02/15 07:53 PM
10/02/15 07:53 PM
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Olympia, Washington
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Del Offline OP
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[b][/b]
Originally Posted by KurtZ
Originally Posted by bleak
I wonder if the positive attributes of laminated soundboards can also be applied to carbon-fiber composite soundboards.


I've watched carbon fiber composites try to gain traction in several musical instrument realms, mainly guitars and cellos. They never get past being a niche product. I think one of the reasons is that their harmonic envelope is just different and we like what we're used to.

You identified the problem with, "... we like what we're used to."

I was able to listen to two large Steingraeber grands at the factory in Bayreuth a year or so back. One was fitted with the normal wood soundboard, the other with a carbon fiber board. They were both, of course, magnificent instruments and there were a lot of similarities between the two. But there were also some differences. I found the differences interesting but I liked both of them. I think many -- possibly not most but it would be interesting to find out -- would have found each of them to be a more than satisfactory instrument. But I also think many -- again, most? -- would have found that they didn't really like the piano with the carbon fiber soundboard once they knew it was not wood.

I do know from actual experience that people who initially really liked how a certain piano sounded when they thought it was using a solid spruce soundboard ended up deciding they really didn't like it all that much once they learned it was actually using a laminated panel.

I'd love to design a test of this just to find out how much our prejudices affect how we "hear" the piano.

ddf

Last edited by Del; 10/02/15 07:55 PM. Reason: spelling

Delwin D Fandrich
Piano Research, Design & Manufacturing Consultant
ddfandrich@gmail.com
(To contact me privately please use this e-mail address.)

Stupidity is a rare condition, ignorance is a common choice. --Anon
Re: Laminated soundboards [Re: Del] #2465801
10/02/15 10:24 PM
10/02/15 10:24 PM
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Ed McMorrow, RPT Offline
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Great thinking Phacke has brought to the discussion, I have never though much about internal deformation of laminated panels before. One does see exceptional, stable life from well made laminated panels in furniture. I think we in the industry are used to thinking no cracking, no warping equals no deformation.

The surface cracking I have seen in double veneer face solid core laminated piano parts always seem to be associated with highly figured face veneers. Many times burl or heavily mottled face wood veneers have cracks in them. Over time these cracks telegraph in to the finish.

On old Steinways the tops and music desks were made with single face veneer on solid core. These often show cracking in the veneer and delamination at the cracks. Newer Steinways went to two cross ply veneer faces on each side. These hold up extremely well.

When I was at the Kingsburg Piano factory in Yantai, China recently I brought two 8"X12" laminated spruce samples of the type they use in some of the pianos they make. They are about 8.2mm thick with a single face veneer on each side. The veneer faces measure a nominal 0.5mm on one side and 0.9mm on the other. Both veneers and the core are quarter sawn spruce. The grain angle between face veneer and core is 45 degrees. Both face veneers have the grain in the same direction.

The side of the panel with the thicker veneer is curved up. The relative humidity in my shop was 52% at the time I measured.

I don't know if the asymmetry of the veneer thickness is typical of all the panels or is part of a normal deviation in production. I don't know if they pay attention to any natural crown the panel may have when they glue the ribs.

I don't know if there is more than one supplier of panels like this.

Hopefully Del has more experience with this and can fill us in. I certainly appreciate his sharing his experience with us.

I prefer to think of the standard solid spruce soundboard with ribs and bridge as a three ply structure. The role of the bridge in forming/accommodating crown is very significant in my experience to the tone quality.


In a seemingly infinite universe-infinite human creativity is-seemingly possible.
According to NASA, 93% of the earth like planets possible in the known universe have yet to be formed.
Contact: Ed@LightHammerpiano.com
Re: Laminated soundboards [Re: Del] #2465878
10/03/15 04:55 AM
10/03/15 04:55 AM
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Münster, Germany
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Originally Posted by Del

I was able to listen to two large Steingraeber grands at the factory in Bayreuth a year or so back. One was fitted with the normal wood soundboard, the other with a carbon fiber board.......

....I think many -- possibly not most but it would be interesting to find out -- would have found each of them to be a more than satisfactory instrument. But I also think many -- again, most? -- would have found that they didn't really like the piano with the carbon fiber soundboard once they knew it was not wood......

....I'd love to design a test of this just to find out how much our prejudices affect how we "hear" the piano.


During a Steingraeber factory training I played both grands you mentioned. We were 12 collegues and there was consensus that one grand sounded much better than the other. After that decision it turned out that the one which sounded better was the one with the normal wood board.

Gregor


piano tech - tuner - dealer
Münster, Germany
www.weldert.de
Re: Laminated soundboards [Re: Gregor] #2466180
10/03/15 10:17 PM
10/03/15 10:17 PM
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Del Offline OP
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Originally Posted by Gregor
Originally Posted by Del

I was able to listen to two large Steingraeber grands at the factory in Bayreuth a year or so back. One was fitted with the normal wood soundboard, the other with a carbon fiber board.......

....I think many -- possibly not most but it would be interesting to find out -- would have found each of them to be a more than satisfactory instrument. But I also think many -- again, most? -- would have found that they didn't really like the piano with the carbon fiber soundboard once they knew it was not wood......

....I'd love to design a test of this just to find out how much our prejudices affect how we "hear" the piano.


During a Steingraeber factory training I played both grands you mentioned. We were 12 collegues and there was consensus that one grand sounded much better than the other. After that decision it turned out that the one which sounded better was the one with the normal wood board.

Gregor

What was it that caused you to prefer one over the other?

ddf


Delwin D Fandrich
Piano Research, Design & Manufacturing Consultant
ddfandrich@gmail.com
(To contact me privately please use this e-mail address.)

Stupidity is a rare condition, ignorance is a common choice. --Anon
Re: Laminated soundboards [Re: Ed McMorrow, RPT] #2466222
10/04/15 01:38 AM
10/04/15 01:38 AM
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Olympia, Washington
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Del Offline OP
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Originally Posted by Ed McMorrow, RPT
On old Steinways the tops and music desks were made with single face veneer on solid core. These often show cracking in the veneer and delamination at the cracks. Newer Steinways went to two cross ply veneer faces on each side. These hold up extremely well.

Most of the old three-ply lids I’ve seen had the face veneers laid up parallel to the core panel. Even though these were technically laminated panels the did have a tendency to warp and crack. Why it took them so long to adopt the five-ply construction that was so common to the rest of the industry is a mystery.


Quote
When I was at the Kingsburg Piano factory in Yantai, China recently I brought two 8"X12" laminated spruce samples of the type they use in some of the pianos they make. They are about 8.2mm thick with a single face veneer on each side. The veneer faces measure a nominal 0.5mm on one side and 0.9mm on the other. Both veneers and the core are quarter sawn spruce. The grain angle between face veneer and core is 45 degrees. Both face veneers have the grain in the same direction.

The side of the panel with the thicker veneer is curved up. The relative humidity in my shop was 52% at the time I measured.

I don't know if the asymmetry of the veneer thickness is typical of all the panels or is part of a normal deviation in production. I don't know if they pay attention to any natural crown the panel may have when they glue the ribs.

Most modern laminated soundboard panels—at least those I’m aware of—have their face veneers laid up at something between 45° to 15° to the core. This angle will make a difference in both stability and tone performance. Life is a compromise; we talk about laminated soundboard panels being more “stable” than their solid panel counterparts—and they are—but they are not perfectly stable. A three-ply panel with the face veneers laid at 90° to the core will be most stable but it but it will perform least like a similar piano using a solid soundboard panel. The 45° grain orientation is a compromise between dimensional stability and tone performance. A panel using a 15° grain orientation will be the least dimensionally stable but can be made to perform most like a solid panel.

Even at 15° the panel will still have very good resistance to cracking. Below about 5° the panel’s resistance to cracking is compromised and it won’t be much more stable that a solid soundboard panel. Much like those lids mentioned earlier. (None of these are absolutes and a lot depends on the characteristics of the wood used and the balance between the thickness of the core and the face veneers.)

I’ve not seen laminated soundboard panels laid up with face veneers made of different thicknesses. Unless somebody actually told you that this was a deliberate specification—which is, of course, possible—I would suspect somebody got carried away with the wide-belt sander.

As far as I know all laminated soundboard panels are made with both face veneers lying in the same direction.

An aside—sometimes panels are deliberately laid up in a way that will force in a more-or-less controlled warp. Baldwin made the panels from which they cut their vertical piano tenor bridge blanks out of two layers of maple. Both layers were of equal thickness. When they were glued up one layer would be at a very low moisture content while the other would be somewhat higher. (I don’t remember the exact specification.) The two layers were oriented at roughly a 30° angle to each other. After the panel was glued up and it acclimatized to the ambient climate it would “warp” and form a crown that roughly matched the crown of the ribbed soundboard panel.


Quote
I don't know if there is more than one supplier of panels like this.

Hopefully Del has more experience with this and can fill us in. I certainly appreciate his sharing his experience with us.

There are several but, not reading Chinese, I can’t tell you much more than that.


Quote
I prefer to think of the standard solid spruce soundboard with ribs and bridge as a three ply structure. The role of the bridge in forming/accommodating crown is very significant in my experience to the tone quality.

Except that the bridge(s) lie more in line with the grain direction of the panel. This still leaves the panel/rib assembly unbalanced. There have been a couple of manufacturers over the years that have laid the grain of the panel across the bridges but they—the companies—didn’t last long.

ddf


Delwin D Fandrich
Piano Research, Design & Manufacturing Consultant
ddfandrich@gmail.com
(To contact me privately please use this e-mail address.)

Stupidity is a rare condition, ignorance is a common choice. --Anon
Re: Laminated soundboards [Re: Del] #2466273
10/04/15 07:13 AM
10/04/15 07:13 AM
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Originally Posted by Del
What was it that caused you to prefer one over the other?


The sound grin

The one with the carbon board sounds not bad, too. After all it´s still a Steingraeber. But the other sounds just better.

Gregor


piano tech - tuner - dealer
Münster, Germany
www.weldert.de
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