Ron wrote... > >> >>The frequency of vibrating piano strings is not stable, but > >tends to > >> >>lower as the string continues to sound. ric wrote > >I would like to see a reference to support this. Ron ...... >Note the pitch in the first half second or so of the attack, and > the drop in pitch as the note continues to sound. ric... I do not have a SAT. If the SAT shows pitch in the first half second different from the pitch in the next 2 seconds and different again from pitch in the next four seconds, that would indeed be most interesting information. Ron ... > * 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? ric.... A decrease in the frequency of the partials was not mentioned. They did conduct experiments to study the amplitude of the partials from 0 time. I believe they were not able to record until a half a second. You would have to read the article to determine exactly what went on. Ron... > 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. ric... From what I got out of the article if there were a pitch drop, it would be a major concern. They were trying to determing the inharmonicity of partials. If the freq of these partials diminished over time I don't see how they could have missed this. The Frequency of these was measured with a chromatic stroboscope, what ever that is. ric (earlier post)... > >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." Ron... > * I don't have a clue one way or another. As an aural tuner, it hasn't come up. ric... Same here. Nor has the decrease of frequency of a piano string over time ever 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. ric.... Tune lab does not show a significant decrease in frequency over time. Other wise with those moving bars it would be impossible to accomplish a tuning. The interesting thing about Tunelab is that you can see how the movement of the bars is affected by .01 cents or .1 cents, or .5 cents or 1 cent. At .5 cents deviation they are moving pretty fast. At .1 cent they are moving fast enough to make you wonder if the machine is really more sensitive than the ear..... : ( Ron... >, you're right that measured inharmonicity is suspect because the ETD > users report that it changes from measurement to measurement. Which is why I would like to see it on an osciliscope. At some point an assesemt of accuracy in the actual recording of frequencies should be made. I assume something like this in in JASA (Jouranal of The Acoustical Society of America). In the few articles I read, it is interesting to see what and how they made their measurements in the 30's 40's and 50's. Perhaps with the observations of Ron and others about frequency shifts it might be time to repeat those experiments with today's state of the art instruments. After all that is the foundation of Science, confirmation through experimentation. I have seen the Conn Stroboscope go first in one direction and then backward. Tunelab can be seen to do that also, but less I think. Each one has issues of accuracy that can be analyzed and tested. ---ric
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