There is so much about guitars many people simply do not know.
String height and tuning
The height of your strings from the fretboard not only effects how easy a guitar is to play, but it effects the tuning as well. On acoustic guitars, the bridge is glued in place, so the distance of the bridge and the frets is constant. If the strings are too high it will not play in tune. Each note is bent out of tune before you ever hit it. Your guitar needs to be adjusted or set up as it is called.
Nut Height and tuning
This is one of the most ignored things on a guitar. All of us know how to crank some screws up and down to change the action, but filing the slots at the nut is tricky business. If the strings are too high at the nut, 1st position chords will be very out of tune and just hurt your fingers to play. This is the case with every guitar you first buy! It’s never a case of IF, it’s a case of how bad the height is. The gap under each string at the nut over the 1st fret should resemble the same gap of a fretted note to the fret in front of it. …..HUH? Your guitar needs a setup.
Frets are so misunderstood. This is the thing that separates the men from the boys, so to speak. Most import guitars (depending on what you pay for it) and even domestically made guitars have bad fretwork.
Here’s the deal! Frets have to be perfectly level and round on top to play and sound good at all, but 9 out of 10 guitars have fret problems! I’m sure the ratio is much worse. It does not matter if it’s a Gibson or a Custom shop Fender, production guitars are made too fast. (see a customer’s comment at bottom). The thing that seems to suffer the most is fretwork. Mostly all it needs is a level and crown.
Every note you press is resting on a fret. Ever wonder why some guitars buzz like a Sitar? The frets are not level and round. The way a Sitar works is the bridge has a flat area in front of where the strings rest at the bridge. Each note buzzes on this flat area to create that Sitar sound. Most production guitars’ frets are somewhat flat shaped creating a Sitar tone on every fret! This is due to the speed in which they are made. It takes time to properly dress the frets! More importantly, it takes great skill! Don’t trust your frets to just anyone!
This is an email exchange I had with a customer.
I did have one question though about the fretboard contouring /shaping that you’re talking about. How is this different than using neck relief, and does it affect the fretboard radius? Thanks!
Something I have discovered over the years are certain flaws in guitar MFG. Companies have to be able to make necks consistent, fast and profitable. And, therefore, cannot afford to pay highly skilled craftsmen to hand radius the necks. So, all necks get made totally flat and level, with whatever radius is specified, which renders a consistent product – This is in contrast to the physics at work in every guitar, and causes a problem:
The lower notes vibrate wider than the higher notes, which causes the lower notes to buzz on the flat surface of the neck.
Therefore, you get your guitar and you set the truss rod tension to allow enough relief to play open chords without buzzing. Then, you fiddle with the saddle height and get them as low as they will go so that the strings will not buzz too bad up past the the 12th fret.This is difficult since the relief has turned the neck into a little ski ramp.
So, you go back and forth compromising between the two. The end result is chords that buzz more than you want and action higher than you want for solos.
“It says (enter big name brand) on the headstock, so it must be good”, right? Wrong!
Ever notice how $100 guitars are just as shiny as $2000 guitars? The first thing to go is good fret work, quality wood and components.
Now to really answer your question. The radius stays the same down the length of the neck…the treble side of the neck gets a slight horizon or a hump the full length of the neck, and the bass side gets this hump from the xxx to the xxx fret then drops slightly to a bowl shape with the highest point behind the xxx fret of the bass side.
When string tension is applied the hump becomes as straight as a laser beam and the bowl more pronounced.
This allows the lowest notes to breathe with the amount of relief they need, without raising the other notes off the neck!!