relevance of bridge pin spacing

[Ron Nossaman]

> The original cap front to rear bridge pin spacing averages 18mm from 
> note 88 to 67 and from 66 to 35 it varies from 19 to 24mm.
> My questions are: Is there anything that could be intentional about this 
> apparently random spacing? Can I change it to 16mm from note 88 to 66 
> and 20mm from 66 to 30 without adverse effects? If there are adverse 
> effects, what would they be?

I'm not sure anyone can say for sure one way or another, but I 
think the low tenor spacing is so wide to compensate for the 
low angle of the string line to the bridge down there, and 
minimize the amount of wood removed by notching. I don't see 
any acoustic or structural benefit, but from a practical 
perspective, it would be easier and quicker to notch by hand. 
I use 18mm spacing, with a little narrower unison, in the top 
section, for #7 pins. Switching to #8 below the top section, 
the unison goes to the width used for the rest of the bridge. 
For the #8 pins, I have three row spacings - 16mm, 18mm, and 
20mm. Where the back row of the higher unison interferes with 
the front row of the lower one, I'll use either the 16mm, or 
20mm to get around it. Otherwise, the rest is 18mm. The bass 
has #9 pins, with 18mm spacing. There's nothing magic about 
any of this that I'm aware of, but this works well for me.


> I have looked very closely at the scale of the plain steel wires and 
> found that if I use the Wolfenden ratios for speaking lengths of octaves 
> and semitones I can create an ideal scale from note 88 to 58 if I 
> shorten the bridge pin spacing by the above amounts - it will give me 
> the fudge room needed. Beyond note 58 to note 35 the tension is slightly 
> low and I can raise it by about 1 to 2 pounds for every 1mm increase in 
> speaking length and the shroter front to back bridge pin spacing will 
> allow this change.
> I have been told that I am splitting hairs.

Well, yea, you probably are, but then how wide was the hair in 
the first place? What's your "ideal" C-8 speaking length?

Ron N