According to various dictionaries, this word is pronounced "hista REE sis," and comes from the Greek hysteros = later, behind. The adjectival form is "hysteretic" ("hista RET ic"). Don't confuse it with words related to Greek hystera = uterus. From the "Concise Science Dictionary," Oxford U. Press: + + + hysteresis -- A phenomenon in which two physical quantities are related in a manner that depends on whether one is increasing or decreasing in relation to the other. The repeated measurement of stress against strain, with the stress first increasing and then decreasing, will produce for some specimens a graph that has the shape of a closed loop. This is known as a "hysteresis cycle." The most familiar hysteresis cycle, however, is produced by plotting the magnetic flux density (B) within a ferromagnetic material against the applied magnetic field strength (H). B ^ | _ + + + P + + Q |+ + + + + | + R + + H - - - - * O * - - - > + + T + | + + + + +| + + S + + + " | If the material is initially unmagnetized at O it will reach saturation at P as H is increased. As the field is reduced and again increased the loop PQRSTP is formed (see graph). The area of this loop is proportional to the energy loss ("hysteresis loss") occurring during the cycle. The value of B equal to OQ is called the "remanance" (or retentivity) and is the magnetic flux density remaining in the material after the saturating field has been reduced to zero. This is a measure of the tendency of the magnetic domain patterns (see "magnetism") to remain distorted even after the distorting field has been removed. The value of H equal to OR is called the "coercive force" (or coercivity) and is the field strength required to reduce the remaining flux density to zero. It is a measure of the difficulty of restoring the symmetry of the domain patterns. + + + Note the generality of the first three lines here, and how, in tuning pianos, we are directly manipulating our tuning wrenches, but only indirectly controlling other things. Imagine sitting at a table with a bullseye target on it. Put an aspirin on the table. Then invert half a walnut shell over it, and a lowball glass over that. Finally, invert a colander over the lowball glass. Your mission (should you choose to accept it) is to center the aspirin, the walnut shell, and the glass, on the bullseye. And there you have it: tuning in a nutshell. The colander of course, is your tuning wrench; the lowball glass is the tuning pin; the walnut shell is the tension on the string; and the aspirin is the tension on the tail end of the string. In one way, we have it easy, because in real life we are only working in one dimension, not two; but then again, we can only observe the "nutshell," (I'm assuming we know what pitch we want!), and we do that by hearing beats, which gets increasingly difficult as we get closer. But there's an important point here which many beginners overlook, and I've known more than one otherwise promising tyro who changed careers over such things. It's not good enough to get the walnut where you want it. You've got to center the tablet inside it. In other words, if you leave the tension on the tail end higher or lower than the tension on the speaking length, you haven't done the job right. How can you do that? Well, there's only one way: by going past the pitch over and over, a little bit less each time. Remember, you can't see the pill, but that's what you're really "tuning." It's time consuming and tedious, and (unless -- like Ben McIlveen, who indirectly convinced me of the necessity of this approach -- you're a concert tuner) the rewards are usually far away, perhaps when some one leaves the windows open overnight, or turns up the heat on a cold winter day. So if you're just beginning to get pretty good at tuning, and hope to reach a new plateau, don't waste your time as I did, struggling for a very pretty tuning that will fail on the first real "test blow," but take the time, and put in the work, to do it right: the hysteretic way. -- Marshall Price Miami, FL d021317c@dcfreenet.seflin.lib.fl.us
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