Ibanez BTB twin truss rods- HOW DO YOU ADJUST????

I've got a bunch of guitars and 1 bass. All have single truss rods and I have no difficulty adjusting neck relief with any of them. Enter my new 5 string Ibanez BTB675 with twin truss rods!

I've never seen dual truss rods before and didn't even know they existed. The neck relief seems to be in spec a the moment, but this being Chicago on the cusp of Spring (it was 61° today) an adjustment is coming soon, particularly as I am planning on changing strings soon. I just want to get it right.

So how do you approach adjusting two truss rods in the same neck??? No instructions to be found with my interwebz search. Is there a link to any kind of instructional video or blog? If not, can someone provide a guide to twin TR's?

Thanks in advance

 

Ok... I did some more research and found a thread that pointed me to the Jerzy Drozd setup guide. So in reading this, he states there are two "styles" of dual truss rods, but I can't find out which style my bass has. You'd think some of this information would be available on Ibanez's website. Can anyone tell me what kind of truss rod system is in the BTB675? Is it a parallel system or a Diagonal Double Truss-Rod System?

 

I can see how it is possible to assume his reference is to dual action, but he actually addresses both. See page 41 of his guide. Mercifully someone from the forum posted the link back in 2012.

I'm inclined to agree with you guys. Jerzy actually advocates using a torque wrench to get even tension. Short of having a torque wrench I would assume that if the bass is set up correctly in the first place and one typically only adjusts a quarter turn, it would stand to reason to adjust each the same amount unless doing so provides an uneven result.

Thanks.

 

Thanks. I can appreciate how it would work that way. I was watching a setup video and the guy said that his natural wood guitars show very little change in neck relief while his lacquered guitars have lots of change. I'm hoping that's the case.

The one question I have when measuring relief is when you have a 24 fret guitar and are checking you fret the first fret.... but which fret do you press up the neck? I know on my J Bass I will depress the 16th fret (as per John Carruthers). Is it the same? Or do you have to push down something further down the neck, especially because this guitar has a 35" scale length?

Ya know... You'd think that Ibanez would post a full instruction manual, but I've searched Ibanez's site, searched the internet and cannot find anything that provides any specific help of specs for this guitar... nor do they answer their customer support inquiries! That concerns me. Completely the opposite experience that I've had with Fender or Taylor.

 

UPDATE:
Thanks for your replies about the twin truss rods. Between the advice here and Jerzy Drozd's manual I was able to figure some things out. Mercifully I've had enough experience setting up Strats and Teles that I'm not afraid of truss rod adjustments and know that "a little dab 'l do 'ya".

As I'm getting more familiar with the bass and comparing the playability to my newly set up (and wonderfully playing) JBass I've started to develop a sense of what a good bass action is. As I was practicing this morning I got the feeling that I wasn't as nimble as I'd like to have been so checked the relief on both sides of the BTB. I've only been used to checking the bass side. The relief over the G string seemed much higher than I was used to while the bass side seemed to have reasonable spacing. So out came the allen wrench and less than 1/8th turn got it where I needed it. I was also able to gently tweak the bass side too. With such a minor adjustment I could feel my touch lighten and my left hand began to feel much more comfortable. Comfortable enough to take it to a rehearsal this afternoon.

Thanks for your help all..... Now I have to learn how to use all these fancy tone controls .

 

Continued update:

So I took the thing to rehearsal yesterday. One thing I've realized is that going from 4 to 5 strings is not only a different experience, when you have to perform on demand and a bit unfamiliar with an instrument without looking it becomes a much more difficult experience. I'd find myself looking away from the music for a second and then getting lost coming back to the music. Also, much more cerebral than artistic.

As far as the truss rod adjustment goes, while it was great while at home, things seemed to have settled and I didn't have quite enough relief at rehearsal, so some notes didn't sustain like I expected and others needed a little more strength in plucking. Also, I found that it affected the overall volume balance from string to string. I'm going to change strings today to DR Pure Blues 45-125's which is one gauge lighter than what's on there so I'll save any further adjustments until I get the new strings on.

I've been doing some continued research to determine if this one is a keeper for me and learned a lot today. I'll tkae those things up on separate thread.

 

Thanks so much for your thoughtful reply. I'm not sure that old strings cause the symptoms, but I did get new DR Pure Blues strings on it tonight. They are a gauge lighter so I'm going to wait til tomorrow to adjust the truss rods and check the string height. Right now the 1st string is only 3/64ths, and the action feels too low and getting a bit of buzzing as expected. I'll let the strings stretch out a bit and then do a TR, then string height and check intonation tomorrow.

The sound with the new strings is night and day different. The feel of these round-wound strings is very similar to the old strings coming off. Not sure what was on there except they're not D'Addarios because all brass colored rings.

And yes, I know it needs a fine fret level which I'll do in the spring or summer after the bass gets acclimated to living in a humidity controlled environment. I had my tech check it out and he said there were a few loose frets and a few unlevel ones. If they are loose, they're not sticking up at all and it plays as if there is nothing loose. I suspect the loose ones (if there are any) may tighten up a bit as the wood takes in the proper amount of moisture. It had a few sharp tangs which I took care of. But those sharp tangs are a sign of wood that has shrunk from dehydration, so I have to think that the looseness will take care of itself.

Thanks again!

 

What I've discovered and should have known is that the upper strings have more tension than the lower strings. Consequently the amount of torque required to create the proper resistance shouldn't be equal with both rods. As I've messed with them I've found it is a balancing act that has no formula. I suppose Ibanez had second thoughts about it as the 675's successor has a single truss rod that can be accessed at the base of the neck rather than under a TR cover near the nut.