Slight modulation-type sounds...

[Bass-desires]

Hey guys I have a strange one for you.

My bass 'modulates'. It didn't really do this before(That I recall) and I am unsure why it is doing it now. When the note is struck (pick or fingers) it rings out the note then modulates a bit down then wobbles a bit before going back to the fundamental. It is quite noticeable.

The strings are old Dean Markley blue steels that I cleaned with denatured alcohol recently, the bridge is tight to the body, and it usually stays in tune.

Would the old strings be the culprit or any other ideas as to the cause of this?

[Bleu]

It's probably a wolf tone. Which happens when the played note match the resonating frequency of the body of an instrument. Sometimes is cause by the pick up magnetic field when it's a bit too close to the strings. Try lowering the pickup height until you can't hear it. If it's still goes on, change the strings.

[Bass-desires]

Hmmmm wow, I've never even heard of that.

[testing1two]

It sounds like one or more of the strings has been twisted when it was reinstalled after the cleaning. Whenever you remove and reinstall strings you have to be very careful not to let them twist.

[Plays_For_Dog]

Is it an active bass? Typically dying batteries distort or clip the note, but... you may get slight wobble with note sustain if your batteries are just starting to tip over the edge.

Bleu really seems to know what he's talking about. Sounds like a really smart answer anyways. If he's correct, then I learned something today and thank Bleu for that.

[Bass-desires]

Hmmm, well I check the strings and 2 out of 4 were a little twisted. Fixed those and checked the sounds. It was a much more stable but still there is a slight change in pitch about 1 second into the note. Maybe I am just hearing natural changes in the note as it sustains.

I did lower the pups a little bit and it helped a little as well, but it still 'waves' a bit in pitch after a second.

Any thoughts or just that I am crazy?

Oh, and it's passive. The bass is an old Epiphone Jazz rockbass with some mods.

[Rusty the Scoob]

Could be a wolf tone but it sounds like old and/or cheap strings to me. (it's been years since I tried Blue Steels, don't remember how they are)

I've had strings do this right out of the package, drives me nuts. I suspect it's a balance issue - if one part of the string is heavier it won't vibrate perfectly and won't stay on pitch.

[JTE]

Two things I'd suspect. First is "Strat-itis" which is the magnets which are the pole pieces exerting enough pull on the strings to deflect them. Lowering the PUPs made it go away some so that's a likely cause.

Second is the old strings are showing metal fatigue and no longer vibrating true.

Jihn