Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Question about Fandrich epoxy soundboard repair

Ed--Hi. Well I will try, We un-glue the ribs, they are always flattened out all unevenly. "mis-shape-en"
We then steam them to saturation which allows the wood resins to soften and the rib can be "manipulated" by hand in a few seconds back to it's "original" shape, and the rib crowned ones have a strong indication that they were that shape to begin with. It is truly amazing that this is so. Steam curving a flat constructed rub, doesn't work so well. we have found. I hope this helps.
Try it yourself.

Chris how old is your CC. Mr. Gertz pianos started out with no SB beveling, right after those screw-stringers. Pretty sure when the double letter model's arrived. around 1900.

I just looked at two MHBB's i have here:
1) #13520 1902 14 Spruce ribs
2) #22918 1913 17 Sugar pine ribs

Same model, two totally different rib scales.

In the post above, i was referring to a clients MHBB which was owned by his grandmother. I was told she was a professional pianist and was friends with Van Cliburn. The piano had a signature H. Mason. The client told me Van Cliburn begged to buy it. It was easy to tell why even in poor condition.

-chris

Chris, the1902, does it have the resonator,?

Blais, I wondered if the pre-Gerts M&H's did not have crown conformed rim. They sound like they don't. And by that I mean they don't have the same tonal signature that the Gertz era bellies have.

I have a 9' screw stringer that I will probably never rebuild. The tone of the piano is not like I expect in a M&H.

It does have the world best sostenuto system. It is impossible to make it clunk. It is the only one of this style mechanism I have ever seen, and current makers should look at adopting the idea in my opinion.

Yes sir, Both have the Resonator.

Hey Ed! we have one of those 9'screw stringer's too. We'll never do either. "what to do with them" ??

We re-crowned an 1899 7'+ M&H and the rim was 90deg all around, no resonator.
We had a 1900 M&H AA and it did have a resonator.
I don't know when the parabolic SB configuration came into play, must have been at that time!. "must have"

Oh,Chris, how can one substantiate if a SB is a moisture-expanded crown or rib crowned, by the rib material????

I asked you how you know that!!!! I'm gonna ask you again? I hope it is not proprietary knowledge.

M&H's were rib crowned pine or no pine period. Gertz only.

Boy!!!!from our experience, not very many manufacturers used spruce for top few ribs, and honestly we don't find all pine ribbing in the ones I have worked on. "little" short pianos maybe.
Many pianos do have all spruce ribs though.

BlaisGuitars,

"How do you know?" is a good question. And i have answered it at least twice.

Third time:
Since none of us was there when the board was made, we have to look at the evidence. And even that is open to human interpretation. So in the end it is just educated guessing.
In some pianos its obvious, and others its hard to discern. One of the processes that makes it difficult to decide is the hand planing of the rib after they are glued on. This of course changes the parallel nature of a straight rib adding to the difficulty.
I have relied on two pieces of evidence, although they are not foolproof.
Generally, It looks to me like tall and narrow ribs are rib crowned. Short wide ribs are compression crowned. This also plays back to the general philosophy of both. RC uses the ribs primarily as load bearers. CC uses the lateral stiffness of the structure. In the boards in which it was easy to observe the type, I saw spruce used in RC and CC. But I have only seen sugar used in CC. You can prove my theory inaccurate if you have a narrow/tall rib scale made out sugar pine. I just haven't seen one. This begs another question. "Since they used Spruce for panels, why the choice of a second species for the ribs? Certainly an unnecessary complication if spruce works. Which i think it comes back to weight. Spruce weighs 28lbs/cu.ft., Sugar weighs 25lbs/ cu.ft., so it makes sense that a load bearing system goes tall for strength, and saves weight by going narrow. Plus there is a 2,000lb difference in bending strength between the two species. So a narrow/tall sugar pine rib would have to be much taller that a spruce rib for load bearing. (10,200psi Spruce, 8,200psi sugar pine).
Here's yet another twist. I am assuming that all the different piano brands were engineered by engineers. Or that they even had any acoustic expertise. In other crafts (violin,guitar) people spend there entire lives perfecting/tweaking a design. Piano soundboards seem very crude in comparison.
You said that my statement of "copying an old board, also copies its mistakes" is ludicrous. I had a 1929 5' Heintzman come in with a board that was a 1/2" thick with no tapering. And all 12 ribs were 1" x 1". I find it hard to believe anyone would copy that. And yes, its the one board, i couldn't tell you if its RC or CC LoL. In actions, changes in action ratios, capstan position, spread,etc., are made all the time to improve performance (fixing mistakes). As is also changing string scales, and various hammer brands are tried to improve tone. Bridge caps, now there is a good one. Would anyone reuse the original bridge cap?? Once that is changed or epoxied, are you really preserving the original tone? So identifying, and fixing mistakes, to improve the tone seems like a natural progression of the art to me.

So here is an area of possible improvement that no one is addressing. If the ribs acoustic job is to transmit energy quickly across the grain of the panel, then maybe the transverse vibration is not so important acoustically but only serves a mechanical function. Longitudinal vibration in a rib may be a significant acoustic importance. To demonstrate here's a neat experiment: Get a metal rod,pipe or tube, about 4 feet long. Hold vertically between your two fingers at various locations along its length. Now hit the end with a hammer. You'll eventually find a sweet spot (one of its nodes) where it will vibrate with a beautiful tone with a long sustain. There are several nodes, but one seems better than the others. All other locations the tone is rather muted.

-chris

Private E-mail's are saying to me if you argue with a fool, then so are you!

There are two ways to accept defeat, gracefully or throwing the pieces across the room.

-chris

Blais: I’ve been following this thread with interest even though I don’t know that much about pianos. I do know something about writing effective arguments.

Chris makes definitive points based on observation and explains how he comes to his conclusions. He has answered your questions thoroughly and noted when he is certain about something and when he is speculating. Even so, maybe Chris’s conclusions are wrong, and yours are right. If so, you should explain why. Instead, you resort to hyperbole and sarcasm which do nothing to support your points. Plus, I don’t know if you’re typing fast on a cell phone, but the poor punctuation and grammar in your posts make them hard to follow.

Again, I don’t know enough about piano soundboards to know who’s right about what. But simply reading your and Chris’s posts, he is clearly more convincing. I don’t know which fool you’re arguing with, but it ain’t Chris.

This being said, I follow and admire your YouTube channel. I hope you can make your PW posts as interesting as your videos. Schoolyard name calling isn’t getting you there.

Double-Ouch!!! Hey! Emery.
I won't argue with you either!.
My grammar school teachers would say if one defends one than "you' must be one. And both would get a slap!
I really can't do any adult name calling here now can I Emery.

That's a lot of noise to make about something you know little about.??? "you" say!.

Com-on!!!!! Chris created his own charts. And expects that to become the standard.

Question, why are you following this thread ???
Again.
I jumped in this poop because of the rhetoric Re: The materials, methods. and results of our efforts in restorations.
And that stinks, and so does that lengthy reprimand. Honest!
I tried, a little, ribs are not joists in a floor. and loud speaker engineering has no place in piano construction.
He hasn't answered any of my questions.
Especially the last one.

Oh! Emery, I forgot to ask you if you ever witnessed such a demonstration. like in the wave videos.
Hampshire piano.

I have just finished polishing up a 1915 A M&H that will be delivered to a new owner, (RIP owner Ginny who passed away recently), that I rebuilt 20 years ago with a new soundboard. It has straight sugar pine ribs on a compression crowned board.

It has that full, smoky singing tone one recognizes as M&H tone. The treble sustain is as long as any piano ever made. I did taper the board more than the original, otherwise I matched original dimensions.

I have never found the loudspeaker analogy useful at all. Loudspeakers are a point source for sound and a soundboard is only a point source for the lower frequencies. In the treble, soundboards are stereo.

Hey Ed! yes two very different zones, that is correct.
And the transition from treble to tenor is the most difficult by far.

I don't know much about soundboards, but I'll chime in again. There''s no difficulty in smoothing out the zones, but if you are recrowning the original board, then you are kind of stuck with the mistakes that are already there.

The reason you may think it's difficult is because you may not fully understand the problem and how others have approached a solution.

I'll address that.

Problem:
Poor interface between zone 1 and zone 2, which is caused by incorrect mass and stiffness. Usually shows up as a dead octave.

Zone 1 area is easily seen in a Chladni pattern of the boards fundamental frequency. Often around 50hz. Zone 2 is the remaining upper 2 sections of the bridge/soundboard.

The Chladni testing that I have done of different soundboard''s show that when the sand goes up into zone 2, the board is too thin and weak. The sand should stop at the plate strut position. The board is weakened by 1)the panel is thinned too much, 2) the ribs are too small, 3) the rib count is too low, 4) or any combination 1,2, or 3.

Steinway diaphragmatic in particular has multiple issues- low rib count, (7 belly ribs) and a too thinned panel, a low rib profile, plus the use of sugar pine may be pushing the envelope.

How others addressed the problem.
Conover (On a crownstay) added extra ribs (9 belly ribs) and smooth rib scale.

Baldwin had another solution. They increased the size of the 2 ribs under the 2ND section. 8 belly ribs.

Mason and Hamlin have a thicker panel and use 8 belly ribs. Plus the rib scale uses more height that the ss.

My process is to run the rib scale through a computer program which calculates the proper dimensions for an even scale and I leave the treble area as the thickest part of the board. And only thin on the long side so that it has the same deflection as the short side.

-chris

I am tired of this nonsense.

*Edited by moderator*

Then by all means move on and don't read the thread. Insulting other forum members will not be tolerated.

Chris, for what its worth, Mason & Hamlin's new VX series Model CC uses quarter sawn sugar pin ribs. They are rib-crowned and each of the 18 ribs has its own radius profile, and are tapered. It also has what they call an acoustic tone bar to center the bridge (bass cut off bar).

"If the ribs acoustic job is to transmit energy quickly across the grain of the panel, then maybe the transverse vibration is not so important acoustically but only serves a mechanical function."

Why? How can the transverse vibration have a mechanical function? We can say that the rib serves a mechanical function, but not the energy passing through it as both longitudinal waves and transverse waves. And both these wave forms are happening at the same time within the rib as long as the note is sounding. The tone of the notes that we are hearing are composed of both these types of waves, always. You are making a distinction that does not exist in the system we are talking about. We cannot really talk about one without the other, so they are of equal importance.

"...here's a neat experiment: Get a metal rod,pipe or tube, about 4 feet long. Hold vertically between your two fingers at various locations along its length. Now hit the end with a hammer. You'll eventually find a sweet spot (one of its nodes) where it will vibrate with a beautiful tone with a long sustain. There are several nodes, but one seems better than the others. All other locations the tone is rather muted"

What you are talking about here is a crude example of a tap tone, usually done on hand held pieces of tonewood, whereby the tip of one's finger is used to tap the piece in various location, to elicit a tone and analyze its composition in terms of liveliness and harmonic content. That is useful for choosing the lumber that will go into the making of a soundboard. You are speaking of nodes and they have their place in the individual pieces, but I think it is too much of a stretch to extrapolate that into the complex system that a piano soundboard is after those pieces are assembled. You will have to do better with your example for it to have any coherence and utility.

The Mason and Hamlin VX CC is a nice piano, but as far as the soundboard goes, a large panel goes a long way in hiding the errors that they have built in. If they are really into being innovative, then they could hire me to install one of my boards and then do a side by side comparison. I believe I would win because i would use a couple acoustic principles that they are not and my Mason and Hamlin Cherno CC would be the bigger piano, and they would hear the difference for sure. But of course they won't.

Here are the errors:

If I read their website correctly, the tone bar puts the bridge in the center of the soundboard. This is a horrible idea. Ask any Timpani player. Whenever you have symmetry the vibration goes out, reflects back and cancels each out. This is why you don't strike in the middle of a drum head. All symmetrical ribs act as a damper. The dampening effect is probably well disguised because of the size of the board, but that means the board could be better still. I most likely would remove the cut off bar (or change the position) to create Asymmetry and an even fuller blend of color and depth.

The tapering (on both sides of the bridge) rib is another inferior idea. This is because the driving point is not only NOT aligned to the bridge (driver), but also can never be adjusted and corrected. Driving points was discovered by the late physicist Jack Frye who was fascinated with the science of the violin. A driving point on a board is the point that accepts all the incoming energy without any dampening. When a driver and driving point are not aligned some sort of dampening occurs. I am just finishing up a series of Baldwin R's for a University project. Since I just learned about the driving points myself, i was only able to use the technology in the last two R's. All i can say is i wouldn't believe it either if i didn't hear it for myself, so i understand the criticism. But, its a huge improvement to the piano. I'm hoping there will be time to have a pianist come out and make a recording.

-chris

Dear reader:

You may notice that Chris all but never answers my questions. When he does not ignore them entirely, he speaks to them obliquely or simply provides an "answer" that has nothing to do with the questions asked but is about what he wants to talk about. As such, in the arena of ideas it is only about winning and not about an exchange where the facts and the best arguments engage on an equal playing field.

Chris, I have not seen or heard the VX CC, nor have I seen pictures of the soundboard, ribs, cut off bar, etc. So I limit my comments to what I know. Last summer, I called Bruce Clark about doing a Zoom technical for my New Hampshire PTG chapter (they did, thanks again Bruce and Mason & Hamlin). Bruce is the designer of the VX series CC and a proud poppa at that, so he spoke at length about the design changes he made, which I found fascinating. I asked about my chapter visiting and having Bruce talk about the VX with us, but Covid still stands in the way of that happening.

When I read your first paragraph, I thought to myself that your vanity knows no bounds. They haven't called me either, but I will choke down my disappointment. :-)

Allow me to offer a few comments about bass cut off bars. They are a very old idea, having been around almost from the beginnings of the piano. They are commonplace in vertical pianos, although not all have then. They are less common in grand pianos and more often used in the larger grands alone. These bars can be straight or curved. The curved bars will more effectively center the bridge in the panel and are used with that in mind. Not all cut off bars are intended to center the bridge, but all work to reduce the differences in length between the two sides. no matter what the design, it is not possible in the high treble and the low tenor to have a centered bridge, due to the shape of the rim.

Makers who use cut off bars presently are such lightweights as Ravenscroft, Steingraeber, Bechstein, Falcone, Bosendorfer, Baldwin, Chris Maene, and Bluthner. I am confident my list is not complete. I forgot Mason & Hamlin.

Representing a perfect circle, a Tympani in no way should be compared with the complex shape of a grand piano. The Tympani may have the canceling effect of which you speak due to the particularities of its simple construction. Your claim that all symmetrical ribs act as a damper in a piano is no more than a supposition for which you have offered no proof.

Why have a cut-off bar? What I will say now will be subject to debate: One reason to do so is to reduce the size of the soundboard. There are areas of a soundboard that are not very efficient with the energy that comes into them and can be regarded as lossy. The bass corner is one of them. Chladni tests show that the sand congregates before it gets into the corner - in other works, it does not contribute much. The argument is that a smaller, more efficient soundboard can be both louder and more sustaining than a conventionally shaped one.

A bass cut off bar also shortens the ribs in the area where they would otherwise be very long.

Because of the straight bass side and the straight belly rail, the reflections of vibration are more chaotic than a curved termination will be. That disorganization has an effect on the clarity of the tone of an instrument.

All that said, I am not a pedant, as I have heard many great sounding pianos with no cut off bar, and many great sounding pianos with cut off bars.

As for having a cut off bar or not having one, this question is an ongoing one in piano design, and many piano makers have played it both ways.

As for the tapering of the ribs of the VX, I used M & H's description. I have not seen their rib, so I don't know exactly what form their tapered ribs take. That could be a straight taper on both sides, or a curved taper. I don't know if "tapering" also includes scalloping as we so often see in pianos. I don't even know if that includes asymmetry, although that is almost always there in the ribs of the high treble at the belly rail.

Lastly, I want to point out that I have never criticized Chris' idea. I have seen pictures of 2 variations of his rib, and I find it interesting. He is an innovator, and I respect that. If it is a good idea, then it will likely improve over time if the merit is there in the finished piano. That means getting quite a few more pianos under his belt with this idea so that he can have a matured frame of reference, where he can get past his own confirmation bias. (And we all can suffer from that with our own ideas).

By the way Chris, you are not the first person to design a rib with the often asymmetrical driving point in mind. My friend Ron Overs, an Australian piano builder and rebuilder, addressed this with his I-rib, albeit in a very different way than you have done: http://www.overspianos.com.au/frameset.html

His philosophy is completely different than yours, so I am confident that you will not like it. I heard a piano that he built in 2006 at the PTG national in Rochester. A spectacularly good piano. And it incorporates just about everything you think is terrible.

Hamburgs (at least D and C) also have cut off bars, embebed at the beams, as newer Steingraeber have (old ones were floating, as most old german grands, including Grotrian). I always have asked me why they did them in this way... Usually when I restore them put the cutoff bar in contact with the belly rail/beams with apropiate wood. This is the place where usually there are the largest ribs... so I am feeling that I am reforcing structuraly the panel, with cleaner sound.
Best