<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; = charset=iso-8859-1"> <META content="MSHTML 5.50.4134.600" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY> <DIV><FONT color=#000080></FONT> </DIV> <DIV><FONT color=#000080>----- Original Message ----- </FONT> <DIV><FONT color=#000080>From: "Farrell" <</FONT><A href="mailto:mfarrel2@tampabay.rr.com"><FONT color=#000080>mfarrel2@tampabay.rr.com</FONT></A><FONT color=#000080>></FONT></DIV> <DIV><FONT color=#000080>To: "Pianotech" <</FONT><A href="mailto:pianotech@ptg.org"><FONT color=#000080>pianotech@ptg.org</FONT></A><FONT = color=#000080>></FONT></DIV> <DIV><FONT color=#000080>Sent: November 03, 2002 5:51 AM</FONT></DIV> <DIV><FONT color=#000080>Subject: Re: Better Bass Scale for M&H A</FONT></DIV></DIV> <DIV><FONT color=#000080><BR></FONT></DIV> <DIV><FONT color=#000080>> > > 3.  With out doing a more = complete analysis, my gut feel tells me there is<BR>> > > very little = pivoting at the traditional hitch pins.<BR>> > <BR>> > There is none. = The string lays across a flat in front of the hitch. This<BR>> > = felt-covered flat varies from as little as perhaps 10 mm (if you're lucky)<BR>> = > to as much as 25 or 30 mm. It's out there that the string has to try = to<BR>> > bend.<BR>> <BR>> I think this is the key here. I understand = clearly how moving the bridge is going to free up movement, but I was picturing the traditional loop on a traditional hitch pin pivoting easily at the point = where it is wedged into the hitch pin & plate. This wedging certainly will = restrict a pivoting motion, and you are right that there is often some = felt or shelf or whatever in front of the hitch pin further restricting any = pivoting motion at the hitch pin.</FONT></DIV> <DIV><FONT color=#000080></FONT> </DIV> <DIV dir=ltr style="MARGIN-RIGHT: 0px"><FONT face="Comic Sans MS" color=#000080>Ah, but there is ALWAYS some felt or shelf or whatever = along the hitchpin riser in front of the hitchpin. It must be there for the = support of the hitchpin. Though not as much as is often provided. (Back in the dark = ages I used to grind off some of that shelf to increase the backscale length. = Switching to vertical hitches is much easier and more effective.) And then there is = the twist that extends some distance beyond that. Keeping in mind that impedance = is primarily stiffness-controlled at low frequencies you can see the = problem developing right there before your eyes (ears?).</FONT></DIV> <DIV dir=ltr style="MARGIN-RIGHT: 0px"><FONT face="Comic Sans MS" color=#000080></FONT> </DIV> <DIV dir=ltr style="MARGIN-RIGHT: 0px"><FONT color=#000080>> = <BR>> I noticed on your M&H A photos that the mono cords had vertical hitch = pins, but the bicords retained the original hitch pins. Any specific reason = for that? I suppose the laws of diminishing returns & benefit-cost analysis = apply as the backscale length increases in the bicord area?</FONT></DIV> <DIV><FONT color=#000080></FONT> </DIV> <DIV><FONT color=#000080><FONT face="Comic Sans MS">My, what sharp = eyes you have, grasshopper! The only reason was cost. This was one of those jobs = in which we were trying to gain the maximum benefit for the least cost. = Originally, we weren't going to do much of anything to the bass bridge other than clean = it up and replace the bridge pins. But as the original bridge cap and much of = the body disintegrated as the pins came out a new bridge body began looking = increasingly desirable. And then, as long as we were replacing the bridge body = anyway, it seemed a good idea to notch it and place it forward some on the = cantilever. As long as we were going that far replacing the mono-chord hitches wasn't = much more of a stretch. I didn't go beyond the mono-chords with the vertical = hitches because the backscale is already some longer up where the bi-chords = start. It's only down toward the very end that they get criminally short.</FONT></FONT></DIV> <DIV><FONT color=#000080><FONT face="Comic Sans = MS"></FONT></FONT> </DIV> <DIV><FONT color=#000080><FONT face="Comic Sans MS">In all, I was = quite happy with the result. </FONT></FONT></DIV> <DIV><FONT color=#000080><FONT face="Comic Sans = MS"></FONT></FONT> </DIV> <DIV><FONT color=#000080><FONT face="Comic Sans = MS">Del</FONT></FONT></DIV> <DIV><FONT color=#000080></FONT> </DIV></BODY></HTML>