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Weird Pulsing - Please Help Me!

Gtowngearhead

Senior Member
Messages
840
So I've got some weird oscillating/pulsing when I hit certain chords and let them ring out... It does it on 2 different guitars, 2 different amps, and 2 different cables, in 2 different places... If both guitars were set up by the same tech, could this be a set up problem???
Please help me guys!!! This is driving me nuts!!!

Thanks
 

Rob Sharer

Muso-Luthier
Messages
2,822
Could be the pickups are too close to the bass strings...the dreaded Stratitis!

See a (guitar) doctor...


Rob
 

David Collins

Member
Messages
2,246
There are different things that can cause "pulsing".

Pickups too close can cause a weird pulsing as Rob said. Bad strings are a common culprit as well.

If you're hearing this only in chords though, you may just be hearing beats, which will be there on any fretted instrument, and most others today as well. The more you overdrive the signal, the more apparent they will be. If this is what you're noticing, there is no cure (other than just not playing thirds, sixths or any other intervals which will beat in equal temperament - pretty much sticking to octaves, fourths and fifths). Making sure it is intonated properly can help, as can lowering the pickups and making sure you're strings are good. In the end though, all instruments will having pulsing intervals to some degree, most noticeable in thirds and sixths in the higher octaves, and amplified by overdrive.
 

Gtowngearhead

Senior Member
Messages
840
Well I get some weird noise out of my low E string. But I just put new THD speakers in my amp so I'm thinking those aren't broke in yet. But the only guitar guy I know in town is the one who set up my guitars... And I set the intonation on my strat and it still does it... So maybe I should set the pickup height.. The guitar tech always sets it to 1/16 of an inch.. Is that too close??
 

David Collins

Member
Messages
2,246
We don't know anything else about your guitars at this point, but in general, yeah, 1/16" is way too close for a neck pickup. Single coils need more clearance than humbuckers, and neck pickups more than bridge. A bridge humbucker may be able to be set 1/16" from the string (when pressed at the last fret), but a neck single coils should be at least 4x that much.

There are a number of things which would be helpful to know in order to offer more well-informed opinions.

1) What kind of guitar/pickups are we talking about here?

2) What kind of strings do you have on it (if your strings are old for example, or you're using something like DR's that would certainly be a possible candidate).

3) Are you hearing this pulsing when playing single notes, or only in chords?

These basic details should at least help us get started.
 

Gtowngearhead

Senior Member
Messages
840
Ok, I'm using a Lite Ash Stratocaster, which has Duncan SSL-1s stock. The strings are Elixer Light-Mediums. I hear the pulsing only on the E string by itself, but EAD together open and any chords have this weird pulsing. And that's on both the SG and the Strat.. I'm not completely sure what strings the SG has, but I think they are Light-Mediums... The pickups are the Hot Rodded Humbucker set from Duncan, which is an SH-2n and an SH-4 in the bridge. The pulsing is bad in the same spots with the SG as the Strat.

The strings are definitely over 5 months old, but they haven't been played in 4 months.

Dave, I definitely appreciate you wanting to get all the details. Shows me that you know what you're talking about and you are actually trying to help.
 

walterw

Platinum Supporting Member
Messages
39,578
david is very much the man.

let me guess, it's the high frets on the low E that warble, right? that 5-month-old string could be the problem, but i'm suspecting the pickups are too close, especially the neck pickups on the bass side, and especially any fender rod-magnet type pickup, which has a lot more pull than a typical humbucker.
 

Gtowngearhead

Senior Member
Messages
840
By the way I'm going to be taking my Strat apart tomorrow to put in an Aluminum shield and a baseplate... What strings should I get?
 

Gtowngearhead

Senior Member
Messages
840
No actually I get the WORST warble out of an A shape chord on the 5th or 7th fret. So a D and an E chord. And the warble on the E string happens open.. I guess I'll play with pickup height...
 

walterw

Platinum Supporting Member
Messages
39,578
oh, here's a screwy thought: is there a ceiling fan in the room? it could be turning at a frequency that's just close enough to interfere with the frequency of certain notes.
 

walterw

Platinum Supporting Member
Messages
39,578
anything else creating a low drone in the room, like an air conditioner or something?
 

David Collins

Member
Messages
2,246
Ha, I forgot about ceiling fans. We removed all four of them when we bought our house a few years back.

Old strings can certainly cause problems. The high E on it's own is most likely bad/old strings, and/or sounds typical of the neck pickup being too high.

The pulsing that is heard only in chords is most likely just beats, which whether you've noticed them before or not, they have always been there and always will. The equal tempered scale we use does not deliver pure intervals, and unless you develop a style to stretch chords in to shape, these beats will never go away by any tricks of setup, intonation, or string choice.

Start with new strings though. Even if it's a temperament issue, old strings can develop odd inharmonicity issues which can exacerbate otherwise minor problems. Sometimes you can chase problems three times to the moon and back, only to find them miraculously disappear when you change strings.

D'addario, GHS, Ernie Ball, John Pearse, major brands like that are fine, or if you like Elixers they are usually just fine as well. Just start with some fresh strings and see how it is. If you also drop the neck pickup the pulsing still seems excessive, then at least you will have ruled out the most usual suspects and we can go from there.
 

Gtowngearhead

Senior Member
Messages
840
Well the pulsing is in all positions... I'm just wondering if lowering the height on all of them would be a good idea.

There's a furnace in the closet... but AC is on the roof, and actually busted right now..

I really appreciate all the ideas guys!
 

cc9cii

Member
Messages
314
At the risk of sounding stupid....

Are you talking about the sound when your guitar's intonation is set badly?
 

David Collins

Member
Messages
2,246
It takes less time to lower the pickups and see if it helps, than it does to type the question. ;)

As to pickup selector position, the pulsing associated with pickup height has nothing at all to do with which pickup is connected to the amp. This is not an electrical or signal problem, it's a result of physical effects on the string's vibration from magnetic pull. It's an issue of proximity of the magnets to the string, and a strong magnetic pull causing odd beats and inharmonicity. Magnets closer to the center of the string length will have greater effect than magnets toward the ends, which is why the neck pickup typically has to be lowered further from the strings than the others.

Old strings, magnetic pull. Assuming you're not talking about typical beating found in all equal tempered thirds and sixths (which I still think is a very real possibility), these are the two most likely problem candidates.
 

Gtowngearhead

Senior Member
Messages
840
Alright well you said neck pickup specifically, I just wanted to check and see if I should lower all pickups. Thanks for the advice guys. I really thought something was wrong with the universe.
 

Gtowngearhead

Senior Member
Messages
840
Ok, so I put in the aluminum pick guard shield an a baseplate... And I put on DR Pure Blues strings. The throbbing has gone away for the most part, and a lot of the noise is gone (thank God), but I'm wondering as to a ballpark level for the pickups?? I was getting some flubiness with the neck pickup and lowered it, but it's only slightly lower than the middle pickup.. And the bridge pickup is slightly tilted forward.. Not sure if that's really bad or not...

Thanks
 

David Collins

Member
Messages
2,246
Aaagghh, you're using DR strings? I'm amazed the pulsing actually went away.

On Strats, the bridge pickup can generally be almost up to touching the strings (when fretted at the last fret), but the neck pickup I adjust to just above flush with the pickguard (1/8" above, as a very generic ballpark guesstimate), and the middle pickup somewhere in between. Easiest way to judge for yourself is to adjust the neck pickup just low enough to not cause any pulsing when playing the 12th fret harmonic on the high and low E's, and go from there as your threshold or reference point.

If you plan on staying with DR strings though, I'd say you just got plain lucky with this set. They are the single most notorious string maker for faulty strings, and as you change strings in the future I would recommend getting two or three sets for every string change to have a better chance of assembling a single good set out of the bunch.
 

Gtowngearhead

Senior Member
Messages
840
Wow. I thought a lot of people on here rant and rave about DR strings. I just wanted to try something new. All the Willis store had was DR, D'addario, or Elixir.. I was gonna try the D'addario chromes but then I remembered flatwound=jazz and that wasn't the sound I was going for.. Any suggestions for a good blues/rock string set?
 




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