Bass setup issue: Warbling notes on A/E string high frets.

[tbonesullivan]

So, I've actually got two bass guitars with this problem, a Carvin B4A, and a MM Stingray. I've been setting these up for a while trying to get the intonation all right and the action where I want it. I set the action on my basses at .100-.110 inches at the 12th fret, so it's a bit higher than the usual "factory" action, which is usually recommended at 3/32", or .094 inches. relief is about a medium pick at the 5th fret with the 1st and 13th positions held down. I have the pickups at or lower than factory.

So, on the high frets on the low E and a bit on the A I get a "warble" in the pitch. It is like the string is not in tune with itself. I have searched, and I've heard everything from a twisted string, to old strings, to the action being too low or the pickups being too high. I checked all that out, and I'm still getting the warbling. Though, it's not like I usually play that high on the E strings, but I don't remember having this before, and now it's there.

Help?

[HAMERMAN]

Are you muting the other strings when you try this? If not the only thing I can think of is that when you play one string the string next to it starts to vibrate slightly. Grasping at straws here. :-)

[tbonesullivan]

Yeah, I tried muting the other strings. I even tried massively lowering the pickups, and that didn't help. Could just be that I need new strings, but they aren't even that old.

[JohnnyB]

Put a clamp on the headstock and see if that works. It could be a resonance problem and the clamp could damp or change that resonant frequency. And I guess it could be the strings--not because they're old but because there's a clash in resonant frequencies between the string winding and the bass neck. Given that two different basses are exhibiting the same warble at about the same place, if you're using the same string model for both it might be the strings--either in their design or a glitch in this production run. What strings are you using?

[tbonesullivan]

The stingray has a set of D'Addario EXL165, which are medium bottoms and light tops, and the Carvin has a set of Carvin strings by La Bella , which are medium but have the same string diameters as the D'Addarios. When I get home I'll try muting the strings on the headstock to see if that helps.

Another thing both basses have in common is they both have big alnico pole humbucking pickups in the bridge position.

[Turdus]

I've had a simlar issue on 2 Jazz basses, but the problem is at the 7th fret on both, and only when plugged into a tube Ampeg bass amp. I don't get the same issue trough a solid state Trace amp. Odd harmonic of some kind for sure.

[tomteriffic]

I'd start by putting some sort of clamp with some mass to it on the headstock. Here's why: A bass, particularly the neck, it like a huge wood chime. It has it's own set of resonances which can act to reinforce or cancel out certain frequencies/notes. Since the frequencies involved are so low, any intermodulation between the string/bass resonances can easily be heard as dead notes, "wildcat" notes, warbles, etc. On a guitar they aren't as noticeable since the frequencies are much higher and are often perceived as just part of the tone of the instrument.

What you're describing sounds like the neck and strings have a resonance that are very close to each other. That would account for the warble since the two would be periodically reinforcing and cancelling each other. By putting a clamp or something massive on the headstock, it changes the resonance of the neck or dampens it and should reduce the resonance to where it doesn't interfere with those notes any more. Groove Tubes used to make a fitted brass plate for the back of bass headstocks for just this purpose.

It's cheap and worth a try, anyway.

[tbonesullivan]

Thanks! I'll give it a try tonight when I have time. I'm really not sure if it's a new problem or not, or whether I just ignored it, since the notes up that high on the E string really don't sound that good anyway.

[tomteriffic]

I almost forgot. If you're playing under a ceiling fan, there may be nothing at all wrong. The air pressure compression/rarefaction caused by the air movement can cause the pitch to vary as it reaches your ears. The bass wouldn't actually warble, your ears would just hear it that way.

I once bought a nice Martin as "damaged" because the store owner had been checking it out while under a ceiling fan. Had the same warble problem. There was nothing at all wrong with the guitar.

[tbonesullivan]

Well, no ceiling fans in the basement, and I've noticed the warble both at home, and in our rehearsal space with a totally different setup. Of course part of me just wants to sell the stingray, and this just adds fuel to that idea.

[JohnnyB]

When I get home I'll try muting the strings on the headstock to see if that helps.

Another thing both basses have in common is they both have big alnico pole humbucking pickups in the bridge position.

What Tomterrific said. Don't use the clamp to mute the strings. Clamp it to the headstock to change and dampen the excited resonant frequency. It's possible the sweet spot humbucker could be aggravating the situation, but since they don't have adjustable polepieces (unlike my G&L) the clamp is probably the more effective solution. Since these are two different basses with different strings and the same problem, perhaps both basses are exciting an electronic resonance (e.g., tube microphonic) in your bass amp? Is it tube or SS?

[tbonesullivan]

The amp is SS, and the stingray has had the issue with two different amps, one in a rehearsal studio, and one in my basement. I'm pretty sure it's someting to do with the basses themselves, either setup, strings, or some weird resonance.

[tbonesullivan]

Ok... update. Just changed the strings on the stingray.

it's still there. I can hear it with the bass unplugged. made sure all of the bridge and neck plate bolts were tight, as well as all the other screws on the bass.

Looks like it's time to clamp something to the headstock.

[murkat]

check the nut slots.

make sure that there is sufficient break angle, tuners to nut slot.

[tbonesullivan]

Checked that. nut slots look fine. Plenty of wrapping to keep the angle steep enough. I think i'm going to bottom out the pickup, and see if it might just be a case of "stratitis" on a stingray. of course, right now I've got to go to a bbq/concert, so I'll do it later today.

I used to have a Fender Jazz Bass (MIM) that had that annoying break angle problem on the A. So I got a mini string tree and all was good. the MM design is pretty good for keeping the break angle steep, and the tuner posts have a taper that pretty much pushes the string right to the bottom.

[JohnnyB]

[tbonesullivan]

Looks like there is no need for clamps. I have an official diagnosis.

I bottomed out the pickup. the warbling was then gone. It's stratitis, on a stingray. now I've gotta figure out what a good pickup height is that won't give me this problem. Also probably should lower the pickup a bit on my carvin.

So, according to EBMM: "The factory specifications for the pickup height is 6/32" or 4.76mm from the top of the plastic pickup cover to the bottom of the G string. The angle of the pickup is set fairly level, so the larger strings are naturally a bit closer. If you haven't already adjusted the pickup or changed to a very heavy gauge string set, you shouldn't have to do any adjustments on the pickup."

Is this supposed to be with the top fret held down or something? My pickup wasn't even that close, but it did this. Maybe it's because I'm using heavier strings? I use medium gauge roundwounds.

[JohnnyB]

What kind of strings (what metal/alloy/etc.) are you using? Formula 52 is the most magnetic followed by pure nickel, followed by NPS (nickel-plated steel), followed by stainless steel, which has the least magnetic pull. Maybe you should try stainless and see what happens.

[tbonesullivan]

I'm using nickel plated steel, medium gauge. This happened with both Labella and D'Addario strings. I may just have to keep the pickup lower. It doesn't seem to impact the sound or volume very much at all. I shoulda figured those big Alnico magnets were the culprit. I'm going to continue messing with it. I like the sound definitely, but I am one who does play up there, and with my SB-2 and Carvin B5 the notes up at the top are perfectly in tune and without any warble. My two basses with big beefy humbuckers in the bridge position? low string warble.

[JohnnyB]

My two basses with big beefy humbuckers in the bridge position? low string warble.

Nor do I have any warble with this one, and I usually use pure nickel wrap or Alloy 52:

[tbonesullivan]

could just be that my stingray is cursed. Of course, their "stock configuration" is for their light gauge strings.

[JohnnyB]

could just be that my stingray is cursed. Of course, their "stock configuration" is for their light gauge strings.

Have you tried lights? That would create a weaker magnetic field disturbance. If you make sure you use a hex core string, you can maintain decent string tension.

[tbonesullivan]

Issue is I play finger style, and lights just don't work for me on a 4. on 5 I can deal with them. I really like the tone and bigger thump I get from mediums. I also like to control the volume with how hard I play, and lights just flop around too much on the A and E.

Hmmm.. I wonder if the Bartolini MM pickups have less magnet pull. they don't seem to be pole-piece based, though they are all black so I'm not sure what the insides look like.

[JohnnyB]

Issue is I play finger style, and lights just don't work for me on a 4. on 5 I can deal with them. I really like the tone and bigger thump I get from mediums. I also like to control the volume with how hard I play, and lights just flop around too much on the A and E.

Hmmm.. I wonder if the Bartolini MM pickups have less magnet pull. they don't seem to be pole-piece based, though they are all black so I'm not sure what the insides look like.

I've never met a USA Bartolini I didn't like. I have a Squier VM Jazz fretless (po' man's Jaco model) into which I put a pair of Bartolini jazz pickups. I was going to thin my heard but this Squier sounds so beautiful I can't bring myself to part with it. And that's with an agathis body and ebonol fingerboard.

[tbonesullivan]

Well that's good. I have always heard good things about them. Question now is, how much do I really like the stingray? It's got a nice sound, yes, but it's kind of a beast. Though, that's where the good sound comes from.

Do you know if the Barts are wired series or parallel? Or do they have enough leads to do series/parallel wiring? Because that would be awesome.

[JohnnyB]

Well that's good. I have always heard good things about them. Question now is, how much do I really like the stingray? It's got a nice sound, yes, but it's kind of a beast. Though, that's where the good sound comes from.

Not sure what you mean by "beast," but I find EB MM Stingrays to be heavy and a bit thick. That wasn't so with the '70s Music Man SRs made at Leo Fender's facility. They were light, responsive, and resonant. Anyway, if you're talking about that wrangling aspect, I hear ya.

Do you know if the Barts are wired series or parallel? Or do they have enough leads to do series/parallel wiring? Because that would be awesome.

Most of the Bart MM pickups have four conductors. They have another model, the MME, which has 3 coils and therefore 6 conductors. See BestBassGear, Bartolini Original Series, and Bartolini Classic Series for options and details. Also note that BestBassGear.com probably has the best pickup and preamp prices you'll ever see. They have excellent service and prompt inexpensive shipping, too. Maybe this would help too.