Dammit, Ron! In the words of Ronald Reagen "There you go again" You're using logic on a logic free subject. When I read Ron O's description of his tuned duplex I thought "OMG, did I make a mistake by eliminating the aliquots in this piano? He did a great job in justifying the tuned duplex, but when I read that it could take 6 mo. to position the aliquots I thought. "What if I don't live that long?" Don't get me wrong, I have great respect and admiration of Ron, but I was looking at it from the human aspect. A great piano coming off the production line, tuned superbly and duplex tuned to perfection. Now Joe Schmuck (pieanna tooner) toons for a concert (he only has 40 minutes to curtain time). He brings the note above pitch and lowers it to tune. He may or may not even know what a duplex scale is let alone know how to tune it. Next tuning is done by Jose Schlock who lifts the pitch to sound good. He knows how to tune a duplex, but he's paid poorly and doesn't have the time to do it. Or the inspiration, for that matter. The result, a great piano that is out of tune for a good portion of its life and a duplex scale that is never in tune. Progress???? You be the judge. I'd better quit before I offend somebody. That's not my intention. Regards to all Carl Meyer Assoc. PTG Santa Clara, California cmpiano@home.com From: "Ron Nossaman" <RNossaman@KSCABLE.com> To: <pianotech@ptg.org> Sent: Sunday, November 04, 2001 7:19 AM Subject: Re: Duplex > >Of course. All of the backscale string segments--at least all of them within > >a reasonable distance from the note being played--are affected. > > Exactly, which is why I've wondered for so long about the presumed benefit > of a tuned rear duplex, especially the idea that the often severely > shortened duplex lengths, while limiting soundboard movement, are > increasing sustain and volume. That must surely be magic. Building systems > with decent soundboards and long free back scales has convinced me, pending > evidence to the contrary, that tuned duplexes are utterly unnecessary. I > can certainly concede that if a system has already been built with a tuned > rear duplex, it probably wouldn't hurt to actually have the duplex in tune, > but I don't see how it is possible for the thing to stay in tune if you did > manage to get it there in the first place. I know that you know this stuff, > but I'd like to lay out a little real world duplex tuning scenario for the > folks at home. > > Why does a string segment go out of tune? After the initial stretching and > settling period, it's because of a change in string length. That's it. > Changing string length changes tension, which changes pitch, whether the > length is changed by the tuner, or by heat or humidity induced dimensional > changes of the bridge and soundboard. If we assume it's bridge and > soundboard rise/fall that changes these string lengths, we must assume that > for any given change to the speaking length, the back scale must change > considerably more because the string length change that affected the string > tensions above the bridge is a higher percentage of the overall length of > the segments below the bridge. Because of the friction at the bridge, > limiting string rendering across the bridge these tension changes aren't > equal above and below the bridge. Depending on whether the pitch is going > up, or down, the back scale will be under either higher, or lower tension > than the front scale. Tensions immediately on either side of the bridge > will be the same for any given string, for very brief periods as they pass > in the night. This will happen at different times in the cycle for each > individual string because segment length proportions are different for each > string. If, on the other hand, the friction across the bridge wasn't any > more than that encountered at the counter bearing bar and V bar, the > segments above and below the bridge would have more nearly equal tensions > and the pitches of the rear duplex and speaking lengths would remain more > nearly, but still not precisely proportional. It isn't, and they won't. > > > > >Why is this > >such a hard concept to grasp? > >------------------------------------------- > >Del > > Now THAT is a mystery that may never be solved. > > Ron N
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