At 22:12 17/09/01 -0500, Ron Nossaman wrote: >...Blending the monochords into the bichords is usually more a matter of >keeping unison tensions similar across the transition and not making >enormous changes in core diameters. That's scaling. By 'unison tensions' do you mean the sum of the tensions of the strings of the unison? If so, then you are saying that a bichord unison with strings at a tension of 180 lbs. each should be adjacent to a monochord at 360 lbs. That would indeed require a huge jump in core diameters and would take the tension of the monochord way above reasonable levels. A typical (and acceptable) singles/bichord break might have the note 14 bichords at 180 lbs. on a No. 19 core with the top monochord note 13 at 260 lbs. on a 20.5 core. Other factors can play a part according to the peculiarities of an instrument and a greater jump in core diameter is sometimes needed. An example would be Note 13 length 1220 mm. o/d 3.15 mm mass 67 gm. tension 268 lbs Note 14 length 1200 mm. o/d 2.55 mm mass 2 x 45 gm. tension 183 lbs. > Blending tone across the bass / tenor break is an exercise in both > soundboard/scale impedance balancing, and good scaling practice. Certainly many more factors come into play here, but in this case the total mass of the top bichord on the bass bridge and that of the lowest trichord on the long bridge might conceivably be similar, especially since on all but the longer grands there is a fall-off in tension towards the bass at the break, often to about 120 lbs. A large increase in tension is required as the transition is made to the top bichords in order to compensate for the increased flexibility (decreased stiffness) of the covered strings. As to "blending the tone", by which I understand matching as far as possible the harmonic balance of the adjacent break notes and not merely avoiding the most shocking of breaks, here the actual design and details of manufacture of the strings also plays an important part. I heard someone say not long ago in front of an audience that a piano needs to be 9'6" long in order to achieve a satisfactory break between steel and covered strings! The transition from plain trichords to covered trichords on the long bridge can be quite problematic and piano-dependent. JD
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