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There's another analysis here:
Five Lectures on the Acoustics of the Piano.

Thak you BDB for that excellent and informative link.

You can learn a lot by poking hammers with one voicing needle, determining which areas are harder than others and comparing it to the tone. Do this on different pianos, and get a better understanding of the piano hammer. Some things are just better done by hand.

del,
please pay no attention to the behind the curtain. you are a very highly valued member of this forum, and you deserve all of our respect and thanks.

i am personally very grateful for the piano education you have given all of us, and hope you realize that you are held in the highest esteem here, and your presence adds tremendous value to this site.

Del, I didn't want to comment in this thread lest I give undeserved attention to your detractor.

However, I must say that I read all of your comments here and in other forums with great interest even when they pertain to things I find trivial or incomprehensible. Must be your writing style.

Thank you for contributing so generously.

BDB,

Excellent! Thank you. Alot of info on hammer hardness. Also much else to look at. Thank you.

I also found MarkS's link as well when researching Estonia pianos... Very interesting as well, but will require my undivided attn when I can give it.

How quickly sides are picked and demarcation lines sketched in this forum.

I personally find worth in both members and would rather they both keep posting information, including occasional backyard rumbles, than try to pick my favourite and blast the other "detractor".

My measuring of this type was done during the mid- to late- '80s and much may have changed among hammer makers since then. But, yes, the numbers you are getting are typical of many hammers. Most of them measured in the high 70s to mid 80s. The problem was that we couldn't come up with any consistent way to determine how hammers with some given Shore hardness readings were going actually sound once they ended up on a piano.

Del

This is the idea. This actually begins to define how the hammer works dynamically. It is a considerable extension beyond what we started to do. It gives an idea of how a specific hammer will actually work when it impacts a set of strings. Simply measuring surface hardness does not do that.

These folks, by the way, (in conjunction with Estonia) are doing some interesting work. While I take exception to some of their conclusions and application their basic investigations are coming up with some good basic information.

Funny you should mention that. This was another technique we tried. Inserting a needle into the hammer at various points while measuring and plotting the force required to press it home. While this was somewhat more reliable than measuring the surface hardness it was still not completely reliable. While I and another individual (who also had some considerable voicing experience) could ‘feel’ the difference it proved to be hard to quantify with numbers. It was also destructive — that is, testing altered the character of the hammer — and we were looking for a completely non-destructive technique.

Del

Since there doesn't seem to be any women looking at the moment, I guess I can throw in my own bit of geek knowledge here...

I think humidity needs to be factored in these hardness measurements. Although there seems to be a common notion that hammers in higher humidity are more "soggy" sounding, I find the situation in fact the opposite, at least in the case of modern hammers with significant tension in them. I find them brighter and believe they are harder. I believe I have also observed a correlation with the tendency of them to break strings.

Wool is hygroscopic and I believe there is a swelling that results from high humidity, making the tension higher. Wool is a kind of hair, of course, and look what happens to the hair on your head when you go from a place of low humidity to one of high humidity. For many of us, we find we have a new, unexpected hairstyle.

Regards,

Rick Clark

hi, rick (woman lurking here, but not sure where the offense lies ).

i had wondered about the role of humidity myself. and the hair analogy is a good one (speaking as one who has naturally curly hair).

when humidity is around 53 percent, my piano sounds its best. in lower humidity, say around 42, i didn't like it as well. derick i think has also posted that his piano (the falcone) had longer sustain at lower humidity.

of course, since my treble hammers were replaced, i'm not noticing an "improvement" at higher humidity any more. but the tonal qualities do still change with even slight shifts in humidity. i find higher humidity confers a warmer richer sound. and lower humidity seems to have a tone with slightly less dimension to it.

i'm only experiencing this within a ten percent range, mind you.

Hi Pique,

My comment relates to a comment I made earlier in the thread.

Humidity also affects the way sound propagates through the air. So when there is a tonal change along with humidity change, one would guess that part of it is due to the change in hammer felt tension (for the tensioned *type* of hammer anyway) but also part of it is due to differences in the air itself.

However, I'm getting altogether too geeky here and must end it now.

Better to listen to music than listen to acoustics.

Regards,

Rick Clark

that would make a great tag line.

thanks for the insights, rick. hadn't thought about the density of the air itself being a factor.

Believe it or not, air is less viscous when it is humid. This has to do with the fact that the oxygen molecules are polar and have "magnetic" interaction with each other. When it is humid, the water molecules interfere with this attraction between oxygen molecules. In my experience, high frequencies are heard better in humid environments.