Multiscale question

[Paul Rhoney]

I'm sitting here drawing up a multiscale design, and came up on a mental road block. How I started, was I laid out the scale length I wanted on the treble side of the neck, and the scale I wanted on the bass side, centered them to each other at the twelfth fret, and then joined each fret. Then, just as a test, I extended each line out to see if they converge at one point... and the don't. So my question is, are they supposed to? Did I not lay that out correctly? Do I need to draw the bass side scale length, the treble side scale length, center them up, and then extend the lines to converge at one point?

[David King]

I don't think they are suppose to. This was a debate I've seen on another forum and it was eventually solved mathematically to everyone's satisfaction. You might try fretfind2d and compare your result which what that generates.

[Peter Wilcox]

You know the fret spacing is correct on both the treble and bass sides. I would measure the scale length down the mid-line of the fret board, then calculate the fret spacing for that length, and measure them on your drawing. If they are correct, then it doesn't matter that their extensions don't converge at a point. Part of the reason that they don't converge may be that the strings aren't parallel to each other.

Here's some discussion of the subject: http://www.projectguitar.com/articles/g ... -fret-r23/

[Paul Rhoney]

I think you guys have eased my concerns. I remember drawing it thinking there was no way I could've possibly f'd it up, but then I remembered other conversations about the fan converging on a point, and it got my head all flustered. I *might" try for a very slightly different method of drawing it, just for one extra level of reassurance. But I'm sure the way I have it now would intonate just fine.

[David King]

A Brit filed a new patent about 10 years back that discusses the errors in the original Novax patent. Don't overthink it.

[Jason Rodgers]

Yeah, don't worry about the secret numerological and geometric coincidences. Give fretfind2d a try: it gives you all the parameters to adjust. If you do just draw it up, make sure that your treble and bass scales follow the outside string paths.

I think you'll like the perpendicular fret at the 12th. I put it at the 7th on my first, and I found it a little confusing looking at the frets above the 12th, as the bass side tilted over the treble. In other words, I was looking at the side dots on the bass side, but the actual treble side frets were a space behind. Of course, I used a 25.5"-27" spread and no fretboard markers, but Strandberg talks about this, too, in an article on his site.

[Paul Kincaid]

If your fingerboard has no taper the frets will converge.