What is the ideal neck relief shape?

Son of Magni · #1 09-09-2007, 08:50 PM

I have my own idea of what it is but I wouldn't want to influence any input here by stating it first (yes, cop out).

So for those that feel they have a pretty good idea of what works best, please describe it or provide a diagram if you have that capability.

SDB Guitars · #2 09-09-2007, 11:12 PM

I'm leaning toward around 3/32" on the G string, 1/8" or so on the E, and 5/32" or so on low B

erikbojerik · #3 09-10-2007, 08:01 AM

This is just me, so YMMV.

Flat to #12 then a gradual curved fallaway; the magnitude of the fallaway will depend alot on your playing style (slappers and those with a heavy RH might need more), but at least 0.010" at #24 as a minimum.

This is the curve along the fretboard (quite apart from the action).

datsgora · #4 09-10-2007, 08:13 AM

I prefer no relief at all......straight as a ruler.....(to use a common phrase)

73jbass · #5 09-10-2007, 08:21 AM

It's whatever works best for you. Purely subjective.

pilotjones · #6 09-10-2007, 09:21 AM

Sadowsky's site gives their standard setup, FYI, IIRC.

erikbojerik · #7 09-11-2007, 05:32 AM

Quote:

Originally Posted by datsgora

I prefer no relief at all......straight as a ruler.....(to use a common phrase)

This kind of fretboard relief WILL give you rattling on the upper frets when you play down by the nut, unless you jack up the action high enough. That's why most folks build in a fallaway on the upper frets.

But high-ish action may be perfectly acceptable to a lot of people. Not everyone ventures up around #12+ where high action is really annoying. And a lot of guys rattle like hell when they play too....some guys will even say "That's where the 'growl' comes from"...

It is interesting....of all the players I talk to, at least half never touch the bridge in any way, ever. The other half will play with saddle height (action), but maybe 85%-90% have never touched the intonation. Maybe a few% have tweeked with the truss rod. I'd venture that the number of players who really know how to do a proper setup (nut slots included) is <1%.

wilser · #8 09-11-2007, 06:25 AM

Quote:

Originally Posted by pilotjones

Sadowsky's site gives their standard setup, FYI, IIRC.

oh dear.

pilotjones · #9 09-11-2007, 08:09 AM

Quote:

Originally Posted by wilser

oh dear.

??

Son of Magni · #10 09-11-2007, 08:26 AM

Ok, so here's my thoughts. First I'm not sure how much I buy into the whole falloff thing. But I play fretless mostly and it may apply more to fretted where fret noise is more of an issue.

The way I've been building the relief is almost all (say 80%) in the first octave, centered around the 7th fret. So if you look at the radius of the relief (not the FB radius), it's increasing as you go up the neck. The idea being to try to have the string to FB angle pretty much constant no matter where you play. And as you move up the FB you need less relief because the saddle height plays a bigger role.

erikbojerik · #11 09-11-2007, 10:03 AM

My take on it is this. The shape of a vibrating string can be approximated (far from the nut) as a half-sine wave (yeah OK its closer to a Bessel function, but let's not get lost in the minutae) with the peak of the wave halfway down the string.

So unfretted, the maximum deflection of the string vibration will be at #12. And fretted strings will have their max deflection at higher and higher frets as you work your way up the neck. That's why fallaway works.

But the shape of the moving string will be more and more flat (less curved) the higher you go on the neck. So you might think that you should have a dip in the fretboard centered on #12 and less fallaway going away from there in both directions. But the problem with this is that if you fret on #12, you'll likely rattle on #24, so all the higher frets need some fallaway.

If anything, it might be good to start the fallaway around #7 (approximating the shape of a vibrating open string) and continue it very gradually from there, but string pull will basically do this for you on the neck itself.

When I do fretwork/setup, with the rod tightened just a bit, I level the frets on a straight line (along the trace of the strings), then mill in at least 0.010" of fallaway between #12 and #24 (checking with feeler gauges), then I'll string up, intonate and do the nut. I'll leave it strung up for a week or so, then I'll adjust the action and intonate again. Usually I'm still rattling/buzzing on the upper frets at this point when I fret in the middle of the neck around #7.

With the strings up at tension for a week, the fret tops always show a bit of relief centered around #7 to #9, so I'll tweek the rod again to try & level this out...but not completely. Adjust the action again, and that helps, but usually I have to go back and add a little more fallaway to keep from rattling with an action that seems low enough for me. This stage is pretty much trial and error, but still checking with a straightedge and feeler gauge to make sure I'm not doing something stupid.

I have a pretty heavy right hand, so maybe I need more fallaway than the average guy...but that's what works for me. I can't see why it would be any different on a fretless.