Richard, You wrote: <<<Upon trying this experiment, I could not hear an appreciable diff between the beat rates, Closer to the truth is that I am not sure if I can hear a difference or not.>>> This is interesting. On every piano where I have tried this, I have always noticed a difference in the A4 region. I just tried this Friday night on my mentor's Steinway grand. There were three of us there. He is an RPT, and we all noticed a slower beat rate in the F3-A4 tenth when two strings of A4 were sounding. We're talking like more than a beat per second slower. <<<In the A4 -A3 octave, single strings, the tenth ended up beating a little faster than the F4-A3 third. With two strings (on A4) it seemed to beat just as fast if not a little faster...>>> The only way I can see that this would happen is if the F3 had slipped in between measuring, the pin of middle string A4 was not set properly, and went sharp during the tuning of the other string; or, that the A4 unison was not just right. Or, maybe I am wacky, and have it all wrong, :-) It's hard to comment on something where I was not present. I am just going on my own experience. <<<Now what about listening to the other side? Suppose you tune a F--A third in single strings. If adding a second string causes the unison to go flat, then if you added a second string to F but left A single, shouldn't the rate of the third now speed up. ? >>> Theoretically, this should happen. But I think that F3 is in the area of the piano where the difference would be much less noticeable. There might be a difference, but it would be less noticeable than in the A4 region. <<<At any rate the, beat rate should return to normal when two strings of F3 are compared to the two strings of A3. In that way this phenomenon whether it exists or not is taken care of aurally just as inharmonicity is.>>> I don't know for sure. If this exists throughout the piano, would every note "correct itselt" when unisons are tuned? For instance, if you strip mute the entire piano and tune the middle string of each note, then come back and tune unisons, could we be so lucky that everything would fall into place? I don't really know, but tuning with 3-string tuned unisons leaves no doubt about it. With all three strings of the lower note of the octave tuned before the upper note of the octave is tuned, you know exactly what pitch you will have. My mentor mentioned Friday that he had noticed some time ago when he was tuning with the strip muting method that he could get everything perfect with the middle string, but after he had tuned the entire strip muted piano, and tuned the unisons to the middle string, the treble was flat; i.e., the 10ths and 17ths were slower than when only the middle strings were tuned. Have you read the PTJ article this month by Bob Stephenson, RPT? It is about tuning vertical pianos, and is entitled " 'Jose Iturbi' Treble Octaves." I quote and agree with his findings: "...a three-string unison sounds at a lower pitch than a single string of that unison. It's easiest to hear this phenomenon while listening to the major 10th." <<<The other thing to watch out for is if the single string itself has a slow beat in it. Listen to the single string as carefully as to a two string unison. I am always surprised at how many single strings have a slow "roll" or actual beat if I take the time to listen. This could cause two strings to "go flat" ??>>> I have noticed this as well. On a grand, seating the strings to the bridge might help. I think the problem you described can be attributed to older strings or bridge problems. I have not noticed this on newly strung pianos--the tone you get from them is very pure. Best regards, John Formsma Blue Mountain, MS
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