Post by Stevie on Nov 22, 2011 23:14:41 GMT
Too many variables here.
1/ The included angle of the strings over the saddle.
2/ Different string gauges / construction leading to variations in the downwards force on the saddle / biscuit / cone assembly.
3/ Neck set angle, and hence the included string break angle with respect to the conewell / cone / biscuit arrangement. (much easier to look at Deuce's sketch than to describe!)
4/ Over or under stringing.
5/ (Ref. item 4/) strings being trapped or otherwise between the tail piece and the cover plate by over or under stringing.
6/ Height of cone + biscuit + saddle.
7/ Depth of saddle slot in biscuit and tightness of saddle in slot. This would affect to what extent any incorrect geometry would have a deleterious effect upon the cone.
8/ Different tunings.
9/ And to some extent, camber (if any) of saddle.
And they are all inter-related. I have ignored truss rod and nut adjustment.
Although I'll readily admit, I have no experience of resos other than working on my own MMB, I'll stick my neck out and state that I believe that one cannot make a statement about any one of these variables without considering the impact that a change would have on all of the others. It should be obvious that I have confined my observations to single cone resos. Perish the thought of dealing with a tri cone!
Constants have to include an assumption that the conewell is fabricated / spun / assembled / soldered into position correctly.
Also, the cone, (assuming that it has been spun) can only ever be an accurate frustum of a right circular cone. and hence can only ever sit normal to the conewell. If the conewell was not constructed accurately, we would not even be having this discussion! By the same definition, the biscuit has to sit normal to the cone because the cone is spun.
I had to make a new saddle for my new NRP biscuit assembly because the standard one was not as high as the Chinese one. To preserve the break angle for the given string gauge, there was no alternative. I did not want to risk damaging anything that I knew almost nothing about.
Michael, is it the string break angle over the saddle that chokes the sound rather than the over or under stringing? Also, in your opinion, would having the strings trapped between the cover plate and the tail piece have any affect because on my MMB, the tailpiece rests very firmly on top of the cover plate? Under stringing actually raises the tailpiece at the same time as altering the break angle. A catch-22 if you will....Should the tail piece be floating if assembled correctly like on a carved top jazz box?
So where are we? I believe that a combination of trial and error together with a good dollop of engineering skill and simple considered common sense led those revered gentlemen to arrive at a design that has stood the test of time. I'd go directly with Michael's analysis because it is founded not on theory like my approach, but on the same multiple tried and tested, time served approach as the Dopyera's. It seems to me that the success of this invention depends on a conjugate match of all the foregoing disparate variables involved. To some extent, one <should> be able to vary one by taking into account the effect on (most) of the others, but why bother re-inventing the wheel? To preserve the optimum geometry one should not make such a crude adjustment to the accepted stringing method to cure a fault.
I over strung my banjo out of ignorance and I never did work out why the strings jumped out of the slots on the saddle, nor why it had lost all of its tone. I even bought a new (higher) saddle off eBay to no avail. Upshot- I had strung it incorrectly and it took a banjo specialist to put me right. He left the new saddle in the case and put my old uncompensated one back on. Here we have a requirement for under stringing but on the reso, it is the opposite way.
Sorry that this post is so long. I normally steer well clear of these topics because of my limited experience, but I can look at the issue as well as the next man. Anyway, it gives those with the superior experience more ammunition to shoot me down! I shan't be offended because I will probably learn something.
1/ The included angle of the strings over the saddle.
2/ Different string gauges / construction leading to variations in the downwards force on the saddle / biscuit / cone assembly.
3/ Neck set angle, and hence the included string break angle with respect to the conewell / cone / biscuit arrangement. (much easier to look at Deuce's sketch than to describe!)
4/ Over or under stringing.
5/ (Ref. item 4/) strings being trapped or otherwise between the tail piece and the cover plate by over or under stringing.
6/ Height of cone + biscuit + saddle.
7/ Depth of saddle slot in biscuit and tightness of saddle in slot. This would affect to what extent any incorrect geometry would have a deleterious effect upon the cone.
8/ Different tunings.
9/ And to some extent, camber (if any) of saddle.
And they are all inter-related. I have ignored truss rod and nut adjustment.
Although I'll readily admit, I have no experience of resos other than working on my own MMB, I'll stick my neck out and state that I believe that one cannot make a statement about any one of these variables without considering the impact that a change would have on all of the others. It should be obvious that I have confined my observations to single cone resos. Perish the thought of dealing with a tri cone!
Constants have to include an assumption that the conewell is fabricated / spun / assembled / soldered into position correctly.
Also, the cone, (assuming that it has been spun) can only ever be an accurate frustum of a right circular cone. and hence can only ever sit normal to the conewell. If the conewell was not constructed accurately, we would not even be having this discussion! By the same definition, the biscuit has to sit normal to the cone because the cone is spun.
I had to make a new saddle for my new NRP biscuit assembly because the standard one was not as high as the Chinese one. To preserve the break angle for the given string gauge, there was no alternative. I did not want to risk damaging anything that I knew almost nothing about.
Michael, is it the string break angle over the saddle that chokes the sound rather than the over or under stringing? Also, in your opinion, would having the strings trapped between the cover plate and the tail piece have any affect because on my MMB, the tailpiece rests very firmly on top of the cover plate? Under stringing actually raises the tailpiece at the same time as altering the break angle. A catch-22 if you will....Should the tail piece be floating if assembled correctly like on a carved top jazz box?
So where are we? I believe that a combination of trial and error together with a good dollop of engineering skill and simple considered common sense led those revered gentlemen to arrive at a design that has stood the test of time. I'd go directly with Michael's analysis because it is founded not on theory like my approach, but on the same multiple tried and tested, time served approach as the Dopyera's. It seems to me that the success of this invention depends on a conjugate match of all the foregoing disparate variables involved. To some extent, one <should> be able to vary one by taking into account the effect on (most) of the others, but why bother re-inventing the wheel? To preserve the optimum geometry one should not make such a crude adjustment to the accepted stringing method to cure a fault.
I over strung my banjo out of ignorance and I never did work out why the strings jumped out of the slots on the saddle, nor why it had lost all of its tone. I even bought a new (higher) saddle off eBay to no avail. Upshot- I had strung it incorrectly and it took a banjo specialist to put me right. He left the new saddle in the case and put my old uncompensated one back on. Here we have a requirement for under stringing but on the reso, it is the opposite way.
Sorry that this post is so long. I normally steer well clear of these topics because of my limited experience, but I can look at the issue as well as the next man. Anyway, it gives those with the superior experience more ammunition to shoot me down! I shan't be offended because I will probably learn something.