Trouble with Pinch Harmonics

R

Rumblefunk

New member
Howdy,

I play a hard tail Jackson Rhoads, 24fret, with two humbuckers: a P-Rails in the neck, and a Custom in the bridge. With each individual pickup engaged (one at a time) I get great pinch harmonics, but with both of them turned on, the pinch harmonics just aren't singing like they should. Does anyone have any idea why this would happen? I don't have my guitar with me right now to tell you guys the scale length if that's of any relevance. I thought maybe it could have something to do with the placement of the pickups with regards to the nodal points of the strings. Or perhaps maybe the two pickups are cancelling out certain frequencies in the harmonic spectrum when engaged together. Any thoughts?...
 
Re: Trouble with Pinch Harmonics

It happens with all guitars. That's why you wont see many strats having bridge/middle wired in series and expecting a great lead tone. I don't know the answer but your first intuition as you describe it seems very normal. Maybe the string over each magnet is vibrating in the opposite relative direction hence the cancelling.
 
Re: Trouble with Pinch Harmonics

I agree with greekdude. Pinch harmonics function the same way as regular harmonic notes insofar as you're causing the string to vibrate from the pinch to the bridge (and of course from the pinch toward the nut/finger). The thing about pinch harmonics is the distance is so much shorter between vibratiion points. This is why one pickup hears it cleanly while the other may not hear it at all, or at worst is hearing the inversion of that and probably canceling most of the signal out.
 
Re: Trouble with Pinch Harmonics

IME If you have separate volume controls on each pickup, then you can roll back one of them a bit and get the pinch harmonics off the other dominant pickup.
 
Re: Trouble with Pinch Harmonics

Rumblefunk said:
Howdy,

I play a hard tail Jackson Rhoads, 24fret, with two humbuckers: a P-Rails in the neck, and a Custom in the bridge. With each individual pickup engaged (one at a time) I get great pinch harmonics, but with both of them turned on, the pinch harmonics just aren't singing like they should. Does anyone have any idea why this would happen? I don't have my guitar with me right now to tell you guys the scale length if that's of any relevance. I thought maybe it could have something to do with the placement of the pickups with regards to the nodal points of the strings. Or perhaps maybe the two pickups are cancelling out certain frequencies in the harmonic spectrum when engaged together. Any thoughts?...
Click to expand...

I think one reason why hotter pickups tend to be better for pinch harmonics is that they have a resonant peak that bumps up the output in the frequency range where the fundamental note moves to when you execute the pinch harmonics, where as vintage output pickups tend to be flatter, and not offer that boost, due their higher resonant frequency. If you combine together the bridge and middle pickup in parallel, the sum inductance drops, and the resonant peak increases. In other words a "hot" bridge and a "hot" neck are not necessarily "hot" when you combine them together by putting the selector in the center position. I'd be curious to know if you get the same problem with the pickups wired in series, as that wiring more will lower the resonant peak rather than raise it. Series mode also raises the overall voltage output, while parallel lowers the output, that could play into things as well.
 
Re: Trouble with Pinch Harmonics

thanaton said:
I'd be curious to know if you get the same problem with the pickups wired in series, as that wiring more will lower the resonant peak rather than raise it. Series mode also raises the overall voltage output, while parallel lowers the output, that could play into things as well.
Click to expand...

Except hot humbuckers in series sound like muddy crap. Real musicians make decisions based on the resulting sound, not technical theory.
 
Re: Trouble with Pinch Harmonics

beaubrummels said:
Except hot humbuckers in series sound like muddy crap. Real musicians make decisions based on the resulting sound, not technical theory.
Click to expand...

I never said it would sound good or bad, I just supposed that it might improve the ease of executing pinch harmonics.
 
Re: Trouble with Pinch Harmonics

beaubrummels said:
Real musicians make decisions based on the resulting sound, not technical theory.
Click to expand...

what if technical theory has help ppl figure out what would get them close to the sound they desire? i.e. mathematics involved in picking individual string gauges? honestly i see no reason not to try both methodologies.
 
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Re: Trouble with Pinch Harmonics

thanaton said:
I think one reason why hotter pickups tend to be better for pinch harmonics is that they have a resonant peak that bumps up the output in the frequency range where the fundamental note moves to when you execute the pinch harmonics, where as vintage output pickups tend to be flatter, and not offer that boost, due their higher resonant frequency. If you combine together the bridge and middle pickup in parallel, the sum inductance drops, and the resonant peak increases. In other words a "hot" bridge and a "hot" neck are not necessarily "hot" when you combine them together by putting the selector in the center position. I'd be curious to know if you get the same problem with the pickups wired in series, as that wiring more will lower the resonant peak rather than raise it. Series mode also raises the overall voltage output, while parallel lowers the output, that could play into things as well.
Click to expand...

Why don't you try this and report back to us your findings....
 
Re: Trouble with Pinch Harmonics

dazedandconfused001 said:
what if technical theory has help ppl figure out what would get them close to the sound they desire? i.e. mathematics involved in picking individual string gauges? honestly i see no reason not to try both methodologies.
Click to expand...

That's valid, but using scientific theory without any testing whatsoever, and with a complete disregard for the actual practical result is what I was responding to.
 
Re: Trouble with Pinch Harmonics

Mine jump out with the bridge pickup (this goes for natural harmonics as well). With both or the neck, it is possible, but not as loud and not as good-sounding (to me). I am sure there is a physics explanation for this, although I don't know it (if anyone knows, tell me). This goes across several guitars and across several types of pickups, so for me, it is a rule. If I want good, loud chirps and chimes, use the bridge pickup.
 
Re: Trouble with Pinch Harmonics

If the guitar has 24 frets then the node of 24th fret position is not on the neck pickup so the neck pup can sense the harmonic.
 
Re: Trouble with Pinch Harmonics

It's not just a frequency game. The distance between the two pickups means there's more cancelling of the extended harmonics; more comb filtering the higher you go. Think about harmonics, they are physically inverting the string's vibration pattern. That's how they work. So if, at a given harmonic frequency, the signal from one pickup is out of phase with the signal from the other, you can't hear the pinch harmonics very well.

Yes, frequency response of the pickup(s) influence it, but bottom line, if you go for a certain harmonic, at a certain location on the string, and the two pickup locations are cancelling that particular harmonic, it's not your fault. (queue Matt Damon in Good Will Hunting)

BTW the 24th fret vs 22nd fret pickup location changes the tone of the pickup's signal, but it's not really related to the location of the 24th fret harmonic. If that were true, it would ONLY be true of open notes anyway. As soon as you press a fret, you've shifted the octave harmonics location.
 
Trouble with Pinch Harmonics

frankfalbo said:
(queue Matt Damon in Good Will Hunting) .
Click to expand...


giphy.gif
 
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