I’d like to demystify what players think is magic about the playability of instruments. So much is measurable. I think it is impossible to set up an instrument well without measuring. Your fingers are incredibly sensitive. I don’t think you can just adjust string height to feel—you need to adjust to measurements, then it will feel right. Veer from that and your instrument will not play as well.
First of all, much of what would be considered a good setup is personal. I don’t believe that there is one perfect setup that will suit everyone. I remember one bass player in an article insisting that the neck has to be dead straight. That is so wrong. Universal action height is a ridiculous concept. I have set up basses for some truly amazing players, and their needs vary. Some like what I would call an average setup- slight bow in the neck, string height 3/32” at the last fret on the first string, graduated to 1/8” under the E or B string. Recently I saw Michael Dimin’s bass (he’s a pretty amazing player). His neck looked dead straight, and his strings were set so close to the fingerboard, almost no one else would be able to play his bass without it buzzing like crazy, ridiculous, but his touch is so light the instrument sings for him. Steve Swallow plays with the highest action I’ve ever seen…that works for him. You need to decide what works for your style of playing, with regard to degree of bow, nut height, and action height. Being able to measure permits you to know exactly what is going on and adjust in very fine increments.
The elements of a good setup that I think are universal include having a nut that is cut where the pressure to push down each string is even. The height could be lower or higher depending on your playing technique. If you have a light touch the nut can be lower. A byproduct of that is better intonation. A heavy touch, the nut a bit higher. Also, the bridge saddles should be set to mirror the curvature of the fingerboard, even if the low strings are higher off the fret board than the higher strings. It makes a huge difference to the way the instrument feels if you pay real close attention to that. I use a machinist’s steel ruler divided in 32nds of an inch to measure. I set it on the last fret and look under each of the strings.
Pickup adjustment: Set the height of the bridge pickup so that it is as close to the strings as is comfortable for you, then adjust it so that the string volumes are balanced. Then, set the height of the neck pickup to be perfectly balanced volume wise with the bridge pickup and make sure it is balanced across all strings.
I hope this makes a difference for you.
Harvey S. Citron