Bass Setup - a few questions

Drew_TNBD

So a few issues with my bass; it plays okay. But I'm sure it could be better. It is a Squier Vintage Modified, left handed. Sounds really nice for the price!

It is tuned to drop-c and I have Rotosound long scale strings on it; 130-105-80-65. When I got the strings it was to hit lower tunings, I did have to file the nut slightly for the 130 string to fit. I think this may have introduced an issue on the low string; whenever I play an open note, it sounds kinda chorusy. Hard to explain, but it is noticeably different from the other strings.

At the 17th fret I have 5mm action, which seems really damn high to me. I can play it, but it doesn't feel all that natural. If I go lower, it gets all clanky and notes choke off. The other strings are about 3-4mm at the 17th fret, but they feel okay, they don't feel too high.

Any thoughts on how I can address these two issues?

stickyfiddle

Stop playing above the 12th fret?

Srsly tho, have you checked the neck relief? 

Drew_TNBD

lol.

I had a look, it does have a fair amount of backbow. Maybe this is the problem and it needs to be straighter?

fretmeister

Truss rod tweak needed.

ICBM

Do you mean that the neck is actually backbowed? If so that's definitely wrong, the relief needs to be forward. Fret the string at the first and last frets while it's in the playing position and have a look at the gap between the string and the 7th-8th frets - it should be around half the G string diameter usually.

The 'chorusy' note may just be because the neck is resonating at a very close frequency - it's usually worse with a very heavy string since it's getting to be a noticeable fraction of the mass of the neck, so it will drive it more easily than a lighter one. It's probably not the nut, even if you haven't cut the groove very well - the width of the nut is only about the same as the string diameter so it won't really be able to vibrate in the groove even if the 'take-off' point isn't at the front.

Drew_TNBD

This is really exaggerated but it's more like the top than the bottom two:

ICBM

OK, that's a forward bow. The middle one is a backbow. You need to tighten the truss rod.

You don't need feeler gauges to check relief! By eye is plenty accurate enough for an initial setting, and more precise than that can only be determined by playing it. It's also very important to do it with the instrument in the playing position, which is often not mentioned - if you lie it on its back the weight of the neck will significantly affect the relief.

fretmeister

Only adjust the truss rod a 1/4 turn at a time. Then let it settle. Slow and safe!

Drew_TNBD

Think I sorted it for the most part. Lowest string still feels a little higher than I'd like, but it'll do pig!

geoffbyrne

'Chorus-y' sounds from the bottom strings is often caused by a twist being introduced in the string when taking it off & putting it on again.

Try (1) taking off the string & making sure that the nut slot slopes downward toward the headstock to give the string a good witness point to end its vibrating length, and, (2) lift the string & make sure there's no twist in it, then carefully put it on, making sure no twist is introduced.  Try it & see if it has improved.

G.