Double Bass Weird bridge/intonation problems

[Wilbyman]

Hey guys-

I'm working my upright chops back up after a 4-5 month slab hiatus. There is just something weird going on with intonation on my bass. I put it on the Peterson strobe tuner and the open D and open G are dead in tune, but the 5-7 fret harmonics are pretty far off.

All the notes on the D and G seem to be playing reasonably in tune but the notes on the E string seem to have migrated 1/3" up the board. It just doesn't feel right. Any help/advice much appreciated.

W

 

[jallenbass]

How old are the strings?

 

[Wilbyman]

Hey J-

I'd say they're about 1 year old or a bit more. Maybe 18-19 months. However, I did take about 4 months off for slabbing as indicated. They don't feel like they're at the point of losing intonation at all.

I will say that the bridge feet don't appear to have moved at all. I outlined the feet in pencil a while back and they're still on. It's a mystery to me.

W

 

[Jake deVilliers]

I'd say that your bridge has tilted.

If the nut is in place and the feet are in the same spot the only way to cahnge the string lengthis by moving the top of the bridge.

Get it up on the dining room table and check it carefully for tilt.
Also make sure the bridge is at 90 degrees to the centre seam/strings.

If all that checks out, move your reference marks. The harmonics ARE in the right place.

 

[Silversorcerer]

What about string height at the end of the fingerboard? It occurs to me that 4 months ago, it was a bit colder / dryer? Some basses do strange things seasonally as they adjust to temperature and humidity changes. If you had been playing on it the past 4 months, this might have been so gradual that you wouldn't notice. But leaving it alone and coming back, it might be more noticeable. When you say it doesn't feel right, is part of that string height?