Hi Richard: You asked for a definition of ghost tones. The late george Defebaugh came up with the term (to the best of my knowledge). When George and I used to team teach at conventions, I brought up the technique of holding down two keys of an interval (to raise their dampers) and then giving a short blow to the key which corresponded to the location of the coincident partials of those two notes. The shock of the bridge and soundboard system coupled with sympathetic resonance would cause the respective partials of the two notes to be excited, thus producing an easily heard beat between the two notes. To prove that the beat was indeed coming from the two notes, if one key is released, the beat stops. If both keys are released, the tone stops. This technique can be used with any interval. The beat locator charts may help the beginners in locating where the various coincident partials occur. A significant point to made here is that there are more than one pair of coincident partials for most intervals. In tuning 5ths in particular, it is so easy to get faked out by the 2nd pair of coincident partials if one does not pay attention. Likewise in M3rds, one can inadvertently be listening to the 2nd coincident partials. In the case of minor 3rds, there are two coincident partials which are only a minor 3rd apart. These can be confusing. The Coleman beat Locator charts can be very helpful in this case. This is not a commercial, you can make your own. That's what I did when I invented the first one. Take a piece of cardboard about 2 feet long, place the edge over the white keys next to the sharp keys. Mark on the cardboard a half inch square above each of the following keys: C28 C40 G47 C52 E56 G59 A#62 C64 D66 E68 Make a second card just like it, but a half inch narrower. These can then be place above the keys at the back of the sharps and with the lowest 1/2" mark placed above each of the two keys of any interval, one can see the keyboard locations where the partials of the two notes coincide. This is where beats can be heard. Quite educational. Jim Coleman, Sr.
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