Adjusting action and relief (specific question)

[Ryan Mohr]

I was reading this Nash guitar set-up guide: http://www.nashguitars.com/Setup.htm and one section struck me as very important. It was under the truss rod adjustment or relief section:

Originally Posted by Nash

Neck/Truss rod adjustment. A neck should have slight "relief". This means that it should have the slightest bit of concave bow. Once again playing styles do have some impact in the area. A player that is really aggressive may want a bit more relief as added string vibration can cause more fret rattle or buzz. There are many theories about just how much relief is correct and some guys use calipers and other tools and get really ultra-fussy in this area. My way of telling if the neck is right is to hold the guitar in the most common playing position tuned normally (gravity will straighten you neck out if you lay it flat on a table, so unless you play lying down do not check this with the guitar flat on it's back). If you do play lying down I think that is really cool. In your playing position, press on the low (thick) E string at the first fret with your fretting hand. With your picking hand, press the last fret on the same string. While holding the string like see if there is just a smidgeon of clearance in the middle of the neck under that string. Smidgeon is a technical term meaning a little thicker than a piece of paper but not as much thickness as a Fender Heavy pick. Do the same test on the high (thin) E string If there is no relief, your neck is over straight and needs to be loosened. If there is too much relief then it needs to be tightened. Truss rods generally need only a quarter to half turn to make a difference. If the testing show that the high and low sides are different which is common as the thing is made of wood and the strings are of uneven tension, adjust for an average. It is better to have less relief on the treble side if that is an option. If the sides are radically different you may need to have a pro look at it to diagnose a possible twist. This is very rare.

So, he is saying that your relief, and therefore action, will be higher in normal playing position--meaning the fretboard is perpendicular to the ground--compared to laying a bass flat on a table. To see the extent to which this is true, I measured the action in both positions and he was right: my action was significantly higher in normal playing position.

So, do you guys adjust these types of things in normal playing position, or do you put your bass down on a table?

[electracoyote]

Good common sense layman's article without being overly scientific and specific.

The measurements should be done in normal playing position. The orientation of the bass during the actual adjustment is inconsequential. I usually stand a bass up when adjusting the truss rod, and sometimes I balance the neck on my knee letting the body weight assist the movement of the truss rod. But again, that doesn't matter. When I go to measure the change, it is always with the bass in playing position.

In addition, I will fret 1st fret with left hand, around 15th fret (same string) with right hand finger 4 (pinky) and not only observe the relief but tap the string with finger 1 (index) somewhere near the middle to more clearly visualize the amount of relief.