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Here are some mainstream wood densities where not all types or exotics are listed.
But this will give a general idea of the difference of using wood Vs stone for a bridge of a piano:

Wood - seasoned & dry kg/cu.m
Afromosia 705
Apple 660 - 830
Ash, black 540
Ash, white 670
Aspen 420
Balsa 170
Bamboo 300 - 400
Birch (British) 670
Cedar, red 380
Cypress 510
Douglas Fir 530
Ebony 960 - 1120
Elm ( English ) 600
Elm ( Wych ) 690
Elm ( Rock ) 815
Iroko 655
Larch 590
Lignum Vitae 1280 - 1370
Mahogany ( Honduras ) 545
Mahogany ( African ) 495 - 850
Maple 755
Oak 590 - 930
Pine ( Oregon ) 530
Pine ( Parana ) 560
Pine ( Canadian ) 350 - 560
Pine ( Red ) 370 - 660
Redwood ( American ) 450
Redwood ( European ) 510
Spruce ( Canadian ) 450
Spruce ( Sitka ) 450
Sycamore 590
Teak 630 - 720
Willow 420

The rock densities in the table below are expressed as specific gravity, which is the density of the rock relative to the density of water. That's not as strange as you may think, because water's density is 1 gram per cubic centimeter or 1 g/cm3. So these numbers translate directly to g/cm3, or tonnes per cubic meter (t/m3). As you can see, rocks of the same type can have any density in a range of densities, since they can contain different proportions of minerals and voids.
Rock densities are useful to engineers, of course. But they're also essential for geophysicists who must model the rocks of the Earth's crust for calculations of local gravity.

Rock density is very sensitive to the minerals that compose a particular rock type. Sedimentary rocks (and granite), which are rich in quartz and feldspar, tend to be less dense than volcanic rocks. And if you know your igneous petrology, you'll see that the more mafic a rock is, the greater its density.

Andesite 2.5 - 2.8
Basalt 2.8 - 3.0
Coal 1.1 - 1.4
Diabase 2.6 - 3.0
Diorite 2.8 - 3.0
Dolomite 2.8 - 2.9
Gabbro 2.7 - 3.3
Gneiss 2.6 - 2.9
Granite 2.6 - 2.7
Gypsum 2.3 - 2.8
Limestone 2.3 - 2.7
Marble 2.4 - 2.7
Mica schist 2.5 - 2.9
Peridotite 3.1 - 3.4
Quartzite 2.6 - 2.8
Rhyolite 2.4 - 2.6
Rock salt 2.5 - 2.6
Sandstone 2.2 - 2.8
Shale 2.4 - 2.8
Slate 2.7 - 2.8
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New age or whatever, I choose to call it 'new age'. Call it what you like, it is not science and has no place in a technical discussion.

I realize many of your points are not 'new age' and may be valid. My advice is to leave the 'new age' out of your descriptions if you want to be taken seriously.

I have a question for all the technicians in this forum:

On a percentage basis, when the hammer hits the string(s) how much signal loss or (energy) occurs before the signal(s) gets to the soundboard on a wood bridge piano?

Sorry, I can't answer that one.
But I am very interested in how the addition of extra dampers was implemented. In most grands there seems to be impossibly little room to add any dampers in the standard configuration. Are there any pictures showing the additional dampers and how they are designed?

That doesn't make any sense. Logic would dictate, based on what you're doing, that higher density would give you more return.

Robert, You keep referring to "My Invention". I don't understand, what did you invent? Simply trying a different material on a 200 yr old design and trying to explain why you think it sounds better doesn't make you Thomas Edison.

Jim, you seem to have missed Robert's point that the crystalline structure of granite is much to be preferred for physical and metaphysical reasons that Robert has expounded at some length.

There are different types of granite and the type chosen for bridges will need to be carefully selected following the results of the exhaustive Research and Development in progress. That programme should of course include other suitable minerals if only to rule them out.

It would be most unfortunate for someone else to come along with a better natural or composite material just as the granite bridge hits the market.

To my ears the defining characteristic of the recordings is an excruciatingly shrill piercing sound that reminds me of recordings of certain well-known sopranos that I have never been able to stand for some reason. I also hear a "metal on stone" quality in the sound, reminiscent of a mason's chisel.

These unfortunate side effects could potentially be mollified by using agraffes as described in Richard Dain's patents which I mentioned in an earlier post.

Supply,

Daniel Koehler owner of Naples Piano Company did the tedious work. Dan is the professional knowing of all functions of the piano I use as reference.
You could call him If you'd like @ 239.404.8007.
He would be more than glad to appease your interests and since Dan did the work I wouldn't share the fruits of his labor without his approval.

OperaTenor,

That doesn't make any sense. Logic would dictate, based on what you're doing, that higher density would give you more return.

ANSWER: Basalt doesn't have the complete mixture of minerals needed for my invention.

The chosen granite I use has the properties I'm looking for even tho I would use Quartzite which has a much higher percentage of quartz than the stone I use @ present and is as hard as basalt and yet has a much better looking matrix.

Logically speaking, in order to conclude all of my tests to be accurate I have to stick with the granite I started with otherwise the tests are not accurate once satisfied with the conclusions, then I will venture into other densities to see what is best for which register. No different than wood bridges consisting of multiple densities for each specific register..

Dave B,

My invention refers to exactly that. I currently hold 2 international guitar patents in which I've produced 23 prototypes 7 of my own models.

I currently hold 3 International trademarks for my company: Stonetone®

1) mark for the name Stonetone®
2) mark for the artwork the name represents.
3) mark For the tag line, Music Of The Earth®

Early spring 2013 I will also hold another International patent on the piano application that's pending until such time.

And several more patents to come for the other stringed instruments within the next 5 yrs, while any of my patents can be extended if any additional technology is produced another file can be submitted under a CIP = [continuation in part], or filing a trademark will protect that entity for ever as long as the maintenance fees stay paid

That makes me an innovator in the (stringed instrument industry) again related to "MY INVENTION(S)".


Lets start with the US Patent Office definition of patent.

"A patent for an invention is the grant of a property right to the inventor, issued by the Patent and Trademark Office. The term of a new patent is 20 years from the date on which the application for the patent was filed in the United States or, in special cases, from the date an earlier related application was filed, subject to the payment of maintenance fees. US patent grants are effective only within the US, US territories, and US possessions.
The right conferred by the patent grant is, in the language of the statute and of the grant itself, “the right to exclude others from making, using, offering for sale, or selling” the invention in the United States or “importing” the invention into the United States. What is granted is not the right to make, use, offer for sale, sell or import, but the right to exclude others from making, using, offering for sale, selling or importing the invention."

So a patent is a property right. That idea for that comes all the way back from the original constitution. That right was granted by the U.S. government to an inventor to exclude others from making, using, offering for sale, or selling the invention throughout the U.S. or importing the invention into the U.S.

Included in this definition of patent is the notion of a limited monopoly. For a defined period of time. In return for that right, the inventor must provide a public disclosure of the invention in the form of the issued patent. Although many people view patents as something that impedes the spread of technology the intent is exactly the opposite. The patent has to completely describe the technology to enable others to copy it - after the period of limited monopoly is over. You can see that intent also in the maintenance fee framework of patents, in which the patent owner has to pay an escalating series of maintenance fees over time - which actually encourages inventors to give up the patent to the public unless they are using it.

The ANSWER to the question I asked prior is between 15% to 30% of the string dynamic due to the wood bridge performance, besides the waveforms conflicting the optimum performance side to side as well as vertically to the soundboard. This calculation doesn't apply to all 88 keys There are several variations.. We can control the attack & decay based on the design and amount of the preferred transducer used.

Now all of you can see the cymascope images that they call cymaglifs " Music Made Visible "

This scientific fact should suffice.

Enlarge for better viewing.

http://youtu.be/rQx_nieKBYY

No one is disputing that the StoneTone bridge has a cleaner, more sustained sound compared to conventional bridges. This video doesn't prove how or why this occurs; it only shows that it occurs. For technicians, this visual representation isn't very useful IMO because we can hear what's happening.

I've been following this thread with interest, though quietly.

My thoughts: Let the product hit the market. If it's a good invention, it will speak for itself. If it's not a good invention, no amount of hype will make it one.

I posted the the cymaglifs to show the partials and that's it, nothing more.
Thank you for your observation Beethoven986.

Hello Loren,

This technology is far from hype in other words, folks such as Thomas Zoells and Dr. Richard Bosworths clarifications and dozens of other folks are privy to this process have all agreed on a very limited test basis that this process is valid and innovative.

As we further this effort in to much better quality pianos to see the significance in improvement with better comparisons since we have certainly validated this concept with the pianos completed thus far..

Anything we can do to improve the quality and or performance of the acoustic piano is our goal.

Our motto defines team as such: Together Everyone Achieves More.

Thank you for your input.

B986,

On the basis of this video I wouldn't say the Story & Clark and Baldwin pianos with granite bridges have a cleaner, more sustained sound than the other pianos, especially the Bosendorfer and Fazioli. It would be interesting to see the attack and decay plots over time.

What was surprising to me was the very marked differences in sound between the pianos. Do you think recording was a factor or are they representative in your experience?

I would. The Baldwin and Steinway concert grands sound especially "dirty" but it's impossible to say from this video whether that's due to slightly mistuned unisons, false beats, or a combination of both... my guess is probably a bit of both. The Bosendorfer sounds much cleaner, but still not like the Fazioli, Baldwin ST, or Hallet ST (and the decay profile is very different). To me, it's a night and day difference between the ST pianos and the conventional ones, but this does not mean I endorse the product (I'm in the Phoenix camp).



Every piano is going to sound different, and the ones tested are all very different in terms of design, build quality, and age. I think the recording of the Hallet is representative of what I heard in person.

986,

Sounds like you heard/played this instrument.

Mass loading of the bass in a standard belly muffles and deadens the 1st 2 octaves, at least in my experiments. Manufactures who are paying attention will go to lengths to keep the mass down back there. Listening to the Youtube clip of the granite bridge, the bass seemed to have been sacrificed for the treble, as it was not at all satisfactory to my ears. True its an entry level piano, so maybe it sounded lousy before the modification...but my small bellies sound quite nice down there, so I don't want to assume what I take as a low frequency tonal deficiency is a small belly issue.

What was your take on the bass tone?

Jim Ialeggio