Is there any acoustic reason for string output unbalance?

[maturanesa]

I have 2 basses: one custom singlecut and a Jazz Bass. With the E and G strings at the same distance from the pup (MM) in the custom bass the E gives twice the signal vs the G. With the Jazz, at the same distance from the pup, the opposite.
So, i assume string mass and magnetic field is not the only reason for unbalance...
Im a bit annoyed with having to mess with pups and string height a lot to get a reasonable balance..
Is there any "acoustic" factor involved? Can you do or change something to get a better string balance acoustically?
thanx

[Jay2U]

It may be caused by the characteristic of the pickup. Here's more about pickups: http://en.wikipedia.org/wiki/Pickup_(music_technology)

[megafiddle]

If it was an acoustic effect, I would expect a difference in sustain, also.
If not, i would say it's all in the pickup.

A heavier string (the E) will normally produce higher output for the same
distance from the pickup. So that one bass sounds normal. Typically, you
lower the pickup on the low string side. E and G pickup gaps are usually not
equal. You do need to set the pickup heights on each and every bass.
Not just for balance, but also for good tone.

The jazz bass sounds unusual, but I can check mine as soon as I get a chance
and see how the pickup gaps are set.

This is a bit of a crude test, but you can touch the tip of a screwdriver or small
steel rod to each of the pickup pole pieces, and estimate their strength by how
hard it is to pull the steel off of the pole piece. They should all feel the same.

[FretlessMainly]

I favor adjustable-pole pickups very strongly for this issue. Some basses get on fine without them, but others are very unbalanced string to string (I use my Alesis 3630 compressor to observe output).

Dimarzio makes a good Jazz replacement with adjustable poles; the DP 123 set. Betwen the PU adjustment screws and the two-per-string adjustable poles, you can nail perfect string-to-string output even when changing strings and/or action. Well worth the $100.