Uneven Bass Volume

[Mincer]

5 string bass is tuned BEADG

Unless the string is the same brand and construction as the other 4, the problem is almost definitely the string. D string might be made of more magnet material than the others

The string was swapped out for one of a bigger size, but the same brand. The issue is still there.

 

[Sam SG]

Maybe try a compressor on his bass.
I know we have had a problem with our bass player playing too loud and I notice certain notes are much worse than others.

 

[ehdwuld]

The D string was swapped out for a bigger size. It is brand new (the other strings are a few months old), so I doubt it is the string itself. Also, the nut wouldn't cause the D to be louder, but quieter (possibly) if it was improperly cut. I will say that the string is the same distance as the other strings over the 1st fret, and this is happening on every note, which takes the nut out of the equation, anyway.

New string with older dead strings full of finger gunk

Yep there's the issue
Bass players are notorious for not changing their strings

Or like yours, just one at a time

He has one new string that is surprisingly louder than his older strings

Hmm

 

[Clint 55]

The D string has the highest tension. Maybe it's more punchy when amplified for some reason.

 

[ehdwuld]

The D string has the highest tension. Maybe it's more punchy when amplified for some reason.

He said it's newer than the others
Thats probably the issue

You know how zingy new strings are
Thats probably what it is
The other 4 are just dead and muted sounding
No mystery

 

[ehdwuld]

Tell him to remove everything all 5 and boil them for about 10 mins

That should remove the finger gunk from the four and level out the sound

I don't know how the larger size string would affect the volume
It shouldn't unless it is massively larger

Like the others said. , may be made different

 

[Mincer]

New string with older dead strings full of finger gunk

Yep there's the issue
Bass players are notorious for not changing their strings

Or like yours, just one at a time

He has one new string that is surprisingly louder than his older strings

Hmm

No, the new string is quieter than the others. That's the issue.

 

[ehdwuld]

My bassist has a 5 string Squier Classic Vibe Jazz Bass, with a stock preamp. Not plugged in, all strings have the same volume. Plugged in, either passive or active, the D string of both pickups is louder than the other strings. Is it the preamp (even in passive?) Could it be *both* pickups (unlikely)? How could we go about troubleshooting this?

That is exactly opposite of your original post