Warwick Thumb BO refuses to intonate.

[Benjamin Strange]

I'm working on a friend's Warwick Thumb BO that just will NOT intonate properly. The action is set kind of high (which is the way he likes it) - 4/32" at the 12th fret on the low B, and 3/32" on the G. All the strings are in tune at the 12th fret, yet they go way out of tune as the strings are fretted beyond the 12th fret. Chords in the 17th-24th fret area are completely unusable. I'm at a loss - the action is even, the spacing is set properly, there isn't any appreciable fret wear on the neck, the string heights are radiused to the fretboard... yet the intonation is still way out of whack. My only guess at this point is that perhaps the strings themselves are wonky; he's using DR taper wound strings, 45-125.

Any ideas as to what to do with this thing? Could the taperwound strings be the culprit?

[crazyguy832]

If it's intonated properly at the 12th fret, there's nothing more you can do. Sounds like the strings may be messing it up (or the high action, but that shouldn't really affect the notes themselves to the point of unplayability).

[Basshole]

Strings, fo sho.

[LeonD]

Are the strings new or old? I only intonate with new strings after they've been played in for a day (to minimize stretching).

I just got a Thumb 4 BO and had no problem with intonation. I'd agree with the above and blame the strings.

LeonD

[NJL]

i would say the strings may be old..

[Benjamin Strange]

The strings are brand new.

[T-Bird]

Hi.

Is the nut cut correctly? That is the main reason for weird intonation problems IME.

You can use a fret-board calculator and measure the fret locations. They just might be off.

Regards
Sam

[CapnSev]

I would say either bad strings, or bad setup. A bowed neck never intonates right.

[funkybassplayer]

Originally Posted by T-Bird

Hi.

Is the nut cut correctly? That is the main reason for weird intonation problems IME.

You can use a fret-board calculator and measure the fret locations. They just might be off.

Regards
Sam

Yeah. What generation of the Just-a-nut does this bass have? I have only had experience with the JAN I but i have never had issues like this with intonating my THumb NT4.

[Benjamin Strange]

It's a beautiful setup - I play for a living, and my roommate (who's also working on it) works as a guitar tech for national touring acts. Both of us are rather perplexed why it's so far out. We're going to take a digital caliper to it and test the fret positions, but other than that I'm at a loss.

[NJL]

have you "stretched" the strings?

[Dan1099]

It won't be the nut.... when fretting, the nut is out of the equation.

IME, it's the high action that's causing the problem. Intonation would never be a problem at all if the strings were laying directly on the frets... Just make sure the frets contact the strings at the correct point, and voila, no intonation problems. Since that doesn't work in anywhere but a theoretical world (duh, if the strings lay on the frets, they wont sound.) the string needs to be higher in the air. Since they need to be pushed down to the fret, you have two effects making the pitch run away: the increased tension added by pushing the string down, and the fret being in the "wrong place" since the string forms the top side(hypotenouse) of a triangle. It's speaking length is slightly longer than the distance from the fret to the bottom of the bridge. Allowing the saddle to move allows you to accomodate this.

Unfortunately, this effect is variable depending on what fret you are pressing down on. You will never get a "perfectly" intonated guitar. But with typical action, you can get one that's close enough that a human ear can't tell, or at least close enough that you won't care. However, with an extremely high action, you're just beyond the intonation systems ability to "make it good enough."

You may find an acceptable compromise where the 12th fret isn't perfect either, but all places are close enough for comfort. Either that, or get your buddy to lower his action. Or be comfortable not being able to intonate up that high. Worked for Paul McCartney.

[Benjamin Strange]

It appears that we're going to have to get my friend to make a concession regarding his bass set up. It's more important for him to be in tune than have a high action, so we're going to straighten the neck out and lower the action and see what happens.

[Benjamin Strange]

Aha! More funkiness: We took the neck off, and discovered a shim. Why would a nice bass like this have a shim in there, straight from the factory? Because the cantaliever which sits over the body wasn't routed properly, causing the neck to kick back and not make contact in the pocket. The cantaliever has a route mark on it, which leads me to believe that the neck didn't quite get finished.

We're shaving the cantaliever down to match the rest of the route, and are going to try to get this thing to sit in the neck pocket properly. I'm sure that's not going to fix the intonation issue, but every little bit helps.

[Dan1099]

It's not uncommon for a bass to come from the factory with a shim. Still, that seems a little wonky to me.

[Roland777]

How much do the strings taper? DR Longnecks are taperwound strings made for through-body stringing, and will result in weird overtones over the 12th fret if strung otherwise.
If the strings taper for more than one inch and a half, they're to blame.