Dear Fred: Thank you for your analysis. In the beginning of Sept. '96 I agreed with you perfectly for most of the reasons which you have stated below. I argued vehemently with Virgil about this. I had just purchased the Reyburn CyberTuner and decided to do some testing. On my Steinway L, I had not been able to convince myself that there was a difference. I had my son give me his impression one day when he stopped by, because I tho't that maybe my old tired ears were just not perceptive enough at age 70. I had carefully tuned a unison, and when I placed a rubber wedge in two of the strings and asked him if the pitch had changed, he said "yes. on the sharp side." So I began a test in earnest. I spent a couple of days doing read- ings. The RCT is a little more sensitive, and I was able to see some diff- erence. The RCT also has a measuring mode where one can get results in hundredths of a cent. The results were more noticeable in the 5th octave than anywhere else. It only amounts to about .3 cents difference. More difference than that is often encountered just in variation from how loud the note is played. But there still is a difference. Before, I had main- tained that there was no difference because I could not read it on the SAT. I did however notice a difference if the unisons were not accurately tuned. So, in my tests, I took pains to tune each string with the RCT, and insist- ed on measured accuracy to within .1 cent. BTW, that is hard to do. I ran tests in the 3rd, 4th, 5th and 6th octaves. The greatest variations were encountered in the 5th octave. The RCT will listen to a tone for 2 to 3 seconds, count the vibrations or calculate the period and then print a number to 2 decimal places representing what it heard. I video taped this test and gave a copy to Dean Reyburn and Virgil when I got to Chicago. Some of the measurements were not so impressive, but I had to admit that the difference does exist. This caused me to tune the top half of my competition piano using both machines (SAT & RCT) on each individual string, trying to compensate for the measured difference and retuning the strings if the net result seemed to slip a bit. This slowed me down a bit, so that it took almost an hour and half to do my tuning. I would encourage your continued testing. You are right that when the 3 strings are not exactly together, you can notice wild differences, even on the sharp side. I think you are correct in the assumption that the eye may transpose the dots to make you assume the pitch rose when in actuality the eye jumped 1 forward instead of 2 backward. Good observation. Since I misjudged once, it's quite possible that I have now misjudged. I know that I have had to retune a lot of unisons since I started looking at the final result. And, this was when there was no pitch raise involved. As late as the convention in Dearborn, I was insisting to Virgil that I did not hear a difference between a single string and the full unison. I felt a little strange when all the rest of the class seemed to hear the difference. Congratulations, you are the first person to respond to my capitulation to Virgil. I really hope you are right. Jim Coleman, Sr, PS I am still convinced that there is more difference psychologically than can be measured physically. There is a difference in tone quality beteen a string and a full unison. This may contribute to Virgil's perception. .. On Thu, 24 Oct 1996 FSSturm@aol.com wrote: > In a message concerning the "Tune-off", Jim Coleman, sr. mentioned Virgil > Smith's contention that a three-string unison is flatter in pitch than its > individual strings, and said that Virgil convinced him it was true. With due > respect, I beg to differ, or at least to state my skepticism. > > When Virgil wrote on the subject about a year ago in the PTJ, I was skeptical > from an aural tuning point of view. I had never experienced the phenomenon, > and I was utterly unable to duplicate it myself. I assumed Virgil was > referring to a psychological attitude rather than a physical fact, and that > he really just wanted to make octaves wide of what would normally be > considered "beatless" in an aural sense in order to prepare for beatless > triple and even possibly quadruple octaves (I have my doubts about the > quadruple ones, except maybe on pianos with really low mid range > inharmonicity, like Kawais). > > Just to verify my conclusions, I decided to test the notion with the help of > my SAT. At first, I was surprised to find what seemed to be evidence in favor > of Virgil's contention. Further testing, however, has led me to doubt it. > > There are several possible scenarios with SAT readings. When strings are > pure, it is possible to tune so as to "stop the lights cold." When this > occurs for all three individual strings of a unison, my experience shows that > the unison will have lights "stopped cold" as well, and at the same pitch. > Whenever I have met with an exception, I have rechecked the individual > strings and found that one or more was "slowly creeping" (it was really > reading slightly sharp or flat, whether because my initial reading wasn't > careful enough or because the pitch had changed). When this was corrected, > the three-string unison registered the same as the individual strings. It > only takes the tiniest discrepancy of one string to override the readings of > the other two. When a pitch raise of one cent is done, often pulling the > second and third strings up will cause the first string to go flat by one or > two tenths of a cent - not enough to make the unison objectionable, or even > noticeably have a "wow", but enough to make the lights rotate. > > Unfortunately, pure strings like this are relatively rare in the upper > regions of pianos, and the movement of the lights has to be interpreted. > There are two main behaviors: 1) lights jump forward (sharp), then rotate > back (flat), and 2) lights jump in one direction or the other, skipping one > or two pairs of lights. Actually there is a third behavior, when a string is > really wild, where the lights seem to dance at random, but let's ignore that > one. (And to be precise, there are all sorts of in between conditions as > well). > > In case 1, I believe the difference between prompt and sustain pitch is what > is being read by the machine. This occurs especially in the top octave and a > half. Normally we tune the prompt (at least I do), playing the note rapidly > in successive blows to get a "stable" reading. When all three strings are > played together, the sustain is longer and more prominent, so it shows up > more clearly than with each individual string. At least this is my experience > and interpretation. In other words, we can get a clearer reading of a longer > sustained tone from the three strings together, and it reads flatter than the > prompt tone we tuned. But if we play the three strings with as rapid a > repetition as we played the singles while tuning them, we'll mostly get > consistent readings for both individual strings and the three string unison. > > Case 2 is difficult to interpret in many cases. I think it is a stroboscopic > phenomenon like when old movies showed wagons with spoked wheels, that > appeared to rotate backward as they slowed down. It is often hard to tell > which way the lights are jumping. Are they jumping two lights to the east, or > one to the west? Often they seem to be stationary, just alternating by one > light from right to left and back, when really they are skipping two lights > and rotating in a particular direction. Sometimes I'll tune two "jumping > light" strings and think I am interpreting them the same, but when I play the > unison I find that I was mistaken on one or even both of them. At any rate, > when there is one or more "jumping light" strings in a unison, this can skew > the way the three strings read together. I think in a majority of cases the > three strings together read flat, but quite often they will read sharp. I > think flat beats out sharp in about a 60/40 ratio, but I am not sure that > this is not caused by my own interpretation of the lights. > > When I look at the whole picture, go through a piano very carefully, checking > and rechecking each string and comparing their readings with their respective > three string unisons, I am unable to find any consistent evidence for the > pitch difference phenomenon that can't be explained by the foregoing. > > So there is my two cents worth on the subject. I write mostly because I hate > to see something like this become a commonly accepted "fact", and fail to be > questioned further, just because somebody with authority and respect has said > it was so. After writing that, I want to say that there is probably nobody > whose opinions I respect more than Jim Coleman's. So Jim, can you explain a > little further how you became convinced? And anyone else have thoughts on the > subject? > > Fred Sturm, RPT > Albuquerque, NM >
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