Truss rod adjustment after lowering action

[CaptainTuna]

I don't really understand this. Why would you adjust the rod before adjusting the saddles? Don't you adjust the rod according to how the strings are set on the bass? The videos I checked out always tell me to take measurements by putting a capo on the first fret and measuring the string height...etc etc...but won't this measurement change once i lower the saddles, thus forcing me to adjust it again?

I know I'm not right, since everyone says you have to adjust the neck first, I just can't understand why.

 

[lethargytartare]

I don't really understand this. Why would you adjust the rod before adjusting the saddles? Don't you adjust the rod according to how the strings are set on the bass? The videos I checked out always tell me to take measurements by putting a capo on the first fret and measuring the string height...etc etc...but won't this measurement change once i lower the saddles, thus forcing me to adjust it again?

I know I'm not right, since everyone says you have to adjust the neck first, I just can't understand why.

So look at how the truss makes the neck bow, so the ends of the neck are "stationary" and the truss changes the bow in the middle. To use that as a primary means of affecting action -- which is a concept relevant to the ENTIRE neck -- you should see how it's not entirely suited to the purpose. It does affect action for a number of frets, but you'd be getting different results at the ends of the fb. The point is that it helps you get CONSISTENT playability and clarity up and down the neck because of the way strings vibrate, and the way they vibrate along the fb when played at different positions, etc. The one thing that really directly affects the truss adjustments is string tension -- so, switch to a higher gauge, and you'll likely have to adjust your truss. And, yes, adjusting saddle height will affect it too, but I think the impact is so slight that you aren't likely to completely wreck the neck's relief with a few turns of a saddle screw...now, if you jacked them up a ton, or bottomed them out, then you might find the need.

And a thorough setup could very easily involve going through "all" of the steps, and then going back to the beginning and rechecking and tweaking everything. The order you see people reference all the time is the one most likely to get you to a good result. And it's particularly valuable if you're just starting out.

As for measuring, you may have left something out -- capo on the first fret, and then FRET near the 15-17th -- when you're measuring relief, you don't measure from first to saddle. If you used a straight-edge, you would just have it along the frets, not all the way back to the saddles. So saddle height doesn't factor in when you're initially setting the relief.

 

[CaptainTuna]

As for measuring, you may have left something out -- capo on the first fret, and then FRET near the 15-17th -- when you're measuring relief, you don't measure from first to saddle. If you used a straight-edge, you would just have it along the frets, not all the way back to the saddles. So saddle height doesn't factor in when you're initially setting the relief.

Yes, I know you have to fret it near the neck...but I just understood why right now! Your post really made things clear, I didn't think the truss rod changed the curvature in the middle but I thought instead that it changed the bow of the whole neck while keeping the neck joint stationary (and not the other one). Now I get how it works.... so if I want to even the buzz as much as possible I guess adjusting the rod is something I HAVE TO do!

Thanks again for clearing things up!

 

[PlungerModerno]

I have never got a neck the way I want it first time around... You need to start the setup from scratch, checking everything each time you adjust the truss rod. It's worth it but it always sucks a bit for a while while the neck settles (sometimes you need to adjust again... tuning will slip sightly etc.).

I try to only change one string at a time for that reason.

 

[Zooberwerx]

Yes, I know you have to fret it near the neck...but I just understood why right now! Your post really made things clear, I didn't think the truss rod changed the curvature in the middle but I thought instead that it changed the bow of the whole neck while keeping the neck joint stationary (and not the other one). Now I get how it works.... so if I want to even the buzz as much as possible I guess adjusting the rod is something I HAVE TO do!

Thanks again for clearing things up!

Excellent observation. The curvature associated w/ properly set relief varies the entire length of the fingerboard with the "zenith" occuring at the ~7-8th frets. Truss rod tweaks have the most profound response in this region with virtually none at the 14-22 frets.

OTOH, I can see where an individual may drop string height, develop buzz, and introduce addt'l relief to compensate. For example, if we start w/ .010" and increase to .013", both are within spec. but even subtle changes can result in dramatic improvements.

Riis

 

[bolophonic]

And generally speaking, low action and heavy attack are mutually exclusive unless you are cool with a lot of rattle or noise.

This.

 

[Chuck King]

Here's an easy way to evaluate the action on your bass.

Play up and down each string. Do they buzz unacceptably anywhere?

No:​

Are you happy with how the bass plays?​

Yes: Congratulations! You're done.​

No: Lower the string height a bit and repeat.​

Yes: If you are getting buzz​

On the low frets by the nut, but not on the upper frets by the body: Add some more relief to the neck, and repeat.​

On the high frets by the body but not on the low frets by the nut: Take some relief out of the neck, raise the string height a bit, and repeat.​

Everywhere: Raise the string height a bit, and repeat.​

Only in one specific place on the neck: Sorry, but you have a high or low fret, and you will need some sort of fret leveling or re-seating---have a tech or luthier check it out.​

When using this procedure, as you get closer, you can make smaller and smaller adjustments. Eventually you will get to the point where it's as good as it can be. If your neck is not warped or twisted and your frets are in good shape, even a cheapo bass can be made to play remarkably well.

 

[69shovlhed]

Yes, I know you have to fret it near the neck...but I just understood why right now! Your post really made things clear, I didn't think the truss rod changed the curvature in the middle but I thought instead that it changed the bow of the whole neck while keeping the neck joint stationary (and not the other one). Now I get how it works.... so if I want to even the buzz as much as possible I guess adjusting the rod is something I HAVE TO do!

Thanks again for clearing things up!

you need to measure the relief before you adjust the truss rod. if you get the relief set perfect, you will get your action as low as possible. if you adjust it without measuring, you could make the action much worse. and you could damage the neck if you adjust it wrong.