Hi Roger, If the partials take time to *develop* then why if you set a tuning device on any partial of a note is there an instant response? Unless you are talking milliseconds. The speed of sound is 1000kph in air. I believe it rises as the density of the material rises. Given the length of most piano wire--how about nano seconds LOL At 12:04 PM 01/22/2000 -0600, you wrote: >Hi Ron, > What I think is happening, each partial takes time to develop, >and is added to the fundamental to for a progressively more complex wave >form. The negative inharmonicity of the partials aids in lowering the pitch. >The inharmonicty increases with a more powerful blow, and is there for mor >noticable with a firm blow. >I'm convincinced that many factors conspire, damping or impedence of the >board, the wire, the hardness of the hammer, the velocity, the regulation, >and so the list goes on. >Just some half baked musings. >Roger > > > > >At 09:46 AM 22/01/00 -0600, you wrote: >>>> >>The frequency of vibrating piano strings is not stable, but >>>tends to >>>> >>lower as the string continues to sound. >>>I would like to see a reference to support this. >> >>* Don't need one, you can verify it for yourself. I seem to remember you >>saying you had a SAT, is that right? If you do, try it out at your next >>tuning. Note the pitch in the first half second or so of the attack, and >>the drop in pitch as the note continues to sound. The pitch drop isn't at >>the same rate through he duration of the sound, but is most rapid >>immediately after attack, and continues at a diminishing rate until it >>stabilizes, or is dropping too gradually for you to tell. I don't know if >>the pitch drop is logarithmic, exponential, polynomial, or just faster at >>the beginning, but it's certainly progressive. I haven't tried it in >>different areas of the scale, so I don't know how the timing differs with >>different string length and mass. >> >> >> >>>Studies done in >>>1943 as reprinted in _Piano Technician's Journal_ Jan. 1964 >>>studied the "measurement of the frequencies of the partials and >>>their amplitudes as functions of time." They did not report a >>>lowering of freq as the string continued to sound ( ie function of >>>time.) >> >>* When I see articles like this, it is usually mentioned in the text that >>the measurements are taken a couple of seconds into the sound envelope, >>after everything has stabilized. Any mention of this in the article? Also, >>they would be concerned with measured partial frequencies relative to the >>measured fundamental at any given point, wouldn't they. The pitch drop most >>likely just wasn't mentioned so it wouldn't confuse the intent of the >>article. >> >> >> >>>An interesting observation that goes contrary to what some say >>>today was that the method of striking the key did not influence the >>>frequencies of the partials, "as it was found that variations in >>>the strength of the blow produced negligible effects on the modal >>>frequencies, the key was struck manually." >> >>* I don't have a clue one way or another. As an aural tuner, it hasn't >come up. >> >> >>> If the frequency >>>really does lower in time, a strobe light should tell beyond all >>>doubt. >> >>* Or a SAT, RCT, Tunelab, Peterson, Conn, etc. >> >> >> >>>What is the need for a mathematical formula to predict >>>inharmonicity.? >>> >>>---ric >> >>* Designing string scales. As a means to compare theoretical inharmonicity >>of one string to another, or a whole scale, it provides a common standard >>for comparison. It beats reading tea leaves or flipping coins. In the real >>world, you're right that measured inharmonicity is suspect because the ETD >>users report that it changes from measurement to measurement. >> >>Ron N >> >Roger Jolly >Saskatoon, Canada. >306-665-0213 >Fax 652-0505 > > Regards, Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T. Tuner for the Saskatchewan Centre of the Arts drose@dlcwest.com http://donrose.htmlplanet.com/ 3004 Grant Rd. REGINA, SK S4S 5G7 306-352-3620 or 1-888-29t-uner
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