Hi,
This Wiki page http://en.wikipedia.org/wiki/Piano_acoustics
presents pretty basic info about piano acoustics, and interesting external links:
http://www.speech.kth.se/music/5_lectures/
http://www.zainea.com/piano%20sound.htm
http://www.afn.org/~afn49304/youngnew.htm
http://www.raeng.org.uk/news/publicatio...2/Dain.pdf
Hope you enjoy it!
Claudio
Thanks for these.
Stretch tunings:
AP Tuner 3 at http://www.aptuner.com/cgi-bin/aptuner/apmain.html is an instrument tuner with 0.1 cent resolution and allows setting a temperament and optional stretch table when tuning an instrument.
If anyone is interested in stretch tables, they are contained in the file "tuner_stretch.xml" and specify 6 different options (the two other BF- tables are for guitars with Buzz Feiten intonation). It should not be too difficult to strip out the numeric data and plot it in a spreadsheet, to get alternatives to the Railsback curve cited currently in the Wiki entry. I have no reference to the sources used in AP Tuner, so cannot vouch to their authenticity or utility.
This will be of theoretical interest only. Pianoteq has only a single "stretch" control which is calibrated in units unknown (although one could use AP Tuner to find out ), but without knowing how it is coupled inside Pianoteq, it seems better simply to "season according to taste".
Of limited interest to pianists. but I have been thinking about the info in those links in relation to the guitar, and the analogies seem close. For example, the point at which it is generally recommend to pluck or strum the strings turns out on my measurement to 1/7 of the length from the saddle. Again, this from a luthier, seems almost as if it could have come from a piano maker:
"Stiffness: The soundboard serves two purposes on a guitar, one as a stable anchor for the strings, and the other as the vibrating unit with which to move air i.e. produce sound. It is this dual purpose that makes stiffness such an important quality. Too much stiffness and it will dampen the tone – too little and the top will distort. Stiffness or lack thereof is something we do grade for and is one of the first things that will get a top downgraded along with major cosmetic flaws. We feel that the stiffer the top, the better (as it comes to you from us), so the top can be made thinner to reduce weight (another tone killer)." (http://www.lmii.com/CartTwo/Secondprodu...D+Tonewood)
Chris Griffiths of Garrison Guitars has introduced a technical devlopment in this area, enabling the soundboard to work to lower frequencies without compromising the structural integrity of the soundboard. Some measurements are shown on their flier at http://www.garrisonguitars.com/pdf/TestResults.pdf.
A difference -- pianists have no need to display their soundboards! Also a guitar seems to be more affected by the connection of the soundboard to the rest of the instrument than is a piano. So the tonal properties of different woods are of interest. A good summary is http://www.pantheonguitars.com/tonewoods.htm.
Another difference is the number of strings, and the sympathetic vibrations. While this may be so for typical 6 string guitars, it is definitely relevant for 12 string guitarists.
I suspect the Pianoteq model could be extended to the guitar without too much mathematical trouble. But while certain preferred woods are becoming rare and/or expensive, which might make it worth doing, it is still possible to obtain a first class instrument at far less cost than a first class piano.