Stratitis on a bass?

[GeoffByrne]

I was doing a setup on a Shine Warrior 5 (J+MM) recently & the customer asked me to hike up the height on the MM pup, which I did.

As I played it certain notes seemed out of tune (sharp), but as I panned to the J pup, the note audibly flattened and it sounded OK. I reduced the height on the MM & it went back to normal.

This is the first time I have experienced this phenomenon on a bass.

Anyone else?

[luknfur]

FWIW:

really has nothing do with strats per se'other than it was a common occurence with them - I guess from guys trying to get more punch, output, whatever from them.

More generically known as wolfe tones (bass tone glossary) resulting from the strings being so close to the magnets they exert a pronoucned pull that alters natural string vibration.

With low tension strings like TI flats or severe attack like popping an EB MM will suck the string fast to the mag.

[PilbaraBass]

Originally Posted by luknfur

FWIW:

really has nothing do with strats per se'other than it was a common occurence with them - I guess from guys trying to get more punch, output, whatever from them.

More generically known as wolfe tones (bass tone glossary) resulting from the strings being so close to the magnets they exert a pronoucned pull that alters natural string vibration.

With low tension strings like TI flats or severe attack like popping an EB MM will suck the string fast to the mag.

something different is going on here...because, the wolf tones would be present as long as the pickup is in that close proximity, regardless of which pickup is actually delivering signal to the amp at the time....

at any rate...if moving the pickup back solves the problem...then leave the pickup as close as you can without getting into this territory...

MM pickups have quite a bit of magnetic pull and they really don't need to be very close to the strings...in fact, if they are exposed pole-pieces...string popping (string popping off the pole pieces and producing loud, annoying "pop" sound) can be a real problem.

[jgsbass]

Its magnet pull causing the chromatic instability.

[PilbaraBass]

Originally Posted by jgsbass

Its magnet pull causing the chromatic instability.

I agree that magnet pull is most-likely the culprit, it's a pretty common problem...

however, the OP's description says that the problem goes away when he pans to the other pickup...perhaps the instability in harmonics is more-or-less limited to around the MM pickup region of the string...but, that doesn't seem likely....in other words, the J pickup should also be sensing the wolf tones (maybe not as badly as I said before, but still there)...

so, either there's a really strange thing happening here, or the OP's account isn't 100% accurate....perhaps he moved the MM back down a bit BEFORE he panned to the J-pickup...

don't know...it would be cool just to have the OP systematically recreate the problem, just for learning sake...

[GeoffByrne]

This OP can systematically recreate the problem simply by raising the MM pickup.

This is exactly the same problem frequently found on Stratocasters (in particular) when the neck pickup is raised too near the strings.

The magnetic pull modifies the vibration of the string (pulling it farther down, and not allowing it to go as high as it would naturally - this tends to accelerate the vibration), and the string goes out of tune, but I've never heard it so *pronounced* as it is here.

If I raise the pickup to maybe 3/8" away from the strings, I can get the note to sharpen by a complete semitone.

Panning to the front J pickup, the note returns to pitch.

Dropping the MM as low as possible brings it back to pitch.

It's obviously to do with the magnetic pull, but as has been said above, it's odd the J pup doesn't sense it, as the MM pup is still pulling on the string.

[luknfur]

FWIW:

Don't know, my guess is in part because the bridge pup isn't reading where the "warp" in the vibration is occurring, also strings vibrate less at the bridge position anyway. I've gotten wolfe tones at the bridge. In my experience, the "warp" will be where the pup that's causing it is.

3/8" from the bottom of the strings having that effect struck me as over the top but I've never put an MM at the neck and the pull of a pair of those huge slugs on large gauge bass strings is a force to be reckoned with I reckon.

I'm no tech head and really don't give it much thought. When a problem is resolved, it's time to play.