<HTML><BODY BGCOLOR="#d8d0c8">Bob D writes and Del respond= s: <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"><BLOCKQUOTE TYPE=CITE style= ="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PAD= DING-LEFT: 5px"> 1) Is there some small change to try next, to improve the treble sustain and= projection, without changing the rib layout, or making a new bridge root?</= FONT> </BLOCKQUOTE> You might try a soundboard = cutoff bar.[SNIP] You might start by recapping the top two treble sections t= o accommodate something resembling semi-log scaling.  </BLOCKQUOTE> I think I can handle a cutof= f bar. Is it necessary to have something showing on the top side of the boar= d, or can it all be underneath? Ron N mentioned that you posted a picture of= an A showing cutoff bar, and I can't find it in my files. Can you send it t= o me? He also mentioed belly rail and long side stiffeners, which I can also= live with. And can you point me to the math for semi-log scaling?<FO= NT COLOR="#000000" style="BACKGROUND-COLOR: #d8d0c8" SIZE=2 FAMILY= ="SANSSERIF" FACE="Arial" LANG="0"> <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"> <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">2) I thought the general deal w= as that stiffer=softer tone/longer sustain and less stiff=louder, more a= brupt. We recently strung a Chickering 109C, the treble of which had both we= ak output AND a very short sustain in the top section. The scale lengths and= sizes looked normal. Whassup? Too much mass? </BLOCKQUOTE> What do you mean, "The scal= e lengths and sizes looked normal....?" What is normal? Where is the hammer = striking point? What are the hammers like?</BLOCKQUOTE> By "normal" I meant they were very similar in the treble to a Steinway A whi= ch sounded very much better. It had some crown, not lots, and we put bearing= on it commensurate with the crown. The hammers shouldn't matter, since the = weakness was also obvious when the strings were plucked. All but the high tr= eble sounded good. I wasn't sure where to look next. <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"> <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">3) A third bridge obviously goe= s on a different spot on the soundboard, with different impedance, and loudn= ess, characteristics from the hockey-stick area of the tenor bridge it repla= ces. How does one figure that difference into the string scale the FIRST tim= e? And would you leave the hockey stick area or cut it away? </BLOCKQUOTE> Are you going to be in Dall= as come July? </BLOCKQUOTE> Alas, it isn't looking like it. I saw your day-long class in Chicago, and ha= ve been perusing the PTJ disks. Eagerly awaiting your book..... <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"> <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">4) What difference do you think= the grain angle to the belly rail makes? </BLOCKQUOTE> In general, as the grain an= gle becomes closer to perpendicular to the bellyrail the stiffness felt by t= he bridge increases [SNIP SNIP] Around the bass bridge this added stiffness = may not be desirable since it will work to increase the sustain of the highe= r partials, something rarely desirable in the bass section. Compensation can= be made by thinning the board out through the bass region or, better yet, p= artially or fully floating the bass region.   It is a good idea to re-orient the ribs to take advantage of any changes mad= e to the soundboard grain angle. Though we don't always.</BLOCKQUOTE> Thanks, I understand the con= cept now, except for how to re-orient the ribs. Do you mean swing them aroun= d in the tenor/bass to keep them perpendicular to the grain of the sbd in th= e bass to help keep the stiffness down, or what? Could they be thinned sligh= tly instead? Sounds like we will save this for another board, because of the= multiple changes, and because I don't think this customer would be happy wi= th a slot in his board. Maybe the M&H A which follows it. I think Dale E= rwin floated a M&H A board with success. I'll see if I can get a look at= it. Thanks, Bob Davis</HTML>