Negative Feedback over Headphones - How is this possible ?!?

Liquid22

Liquid22

Inspired
Hi there,

since V10 was so huge I decided to nail the Slash Use your Illusion sound. Not only because it's very hard to get a solo-track for tone-matching. From the beginning I wanted to get the pure sound just with choosing the right amp and cab and the right tweaking. Within the last months I made some presets from scratch which I thought were close to Slashs sound, but sooner or later I started all over because something was missing or bothers me. So I’m still in progress of tweaking.

Now the thing: After serious and "extreme" tweaking I often come to a point, were I get negative Feedback of the guitar, wile playing just over headphones.
If I would play over real speakers I would say guitar position, pickups, PA-Volume … are creating that negative Feedback. That would make sense imo. But as far as I understand guitar equipment, normally there can’t be any feedback just playing over headphones.

So what’s’ going on there inside the Axe? Are there some well known parameter(s) or knob(s) in the Amp-Block which are responsible for that kind of feedback. I couldn’t figure it out. And how on earth can such negative Feedback over headphone be anyway.

(Btw: No matter how hard I try to compensate it with gates, more or less it’s still there.)
 
It certainly IS possible to get feedback from your headphones, especially if they're cranked. I've had it happen a few times with my Axe and using other equipment as well, under certain situations. It can be exacerbated by high gain especially combined with any high-q filtering done in your chain, like a wah or PEQ, or perhaps even a sharp IR. So if you have any of that going on in your patches, start looking there. The gate only helps with feedback when it's not open. Once it's open the feedback will keep it open just as any normal guitar signal would.

You can get acoustic feedback if the headphones are physically close to the strings/pickups and very loud; they are speakers, after all. You can get electrical feedback from the drivers (similar to "tweeter squeal"). Also, as has happened to me, you can even get feedback from having the headphone cable too close to the pickups, via inductive coupling. Try moving your head and headphone cables and see if the situation changes.
 
I'm not clear on what you mean by "negative feedback." That's something that's usually applied internally in an electrical circuit. Do you mean singing, sustaining, howling or screeching feedback? That would be positive feedback. Negative feedback would reduce your sound level.
 
Rex said:
I'm not clear on what you mean by "negative feedback." That's something that's usually applied internally in an electrical circuit. Do you mean singing, sustaining, howling or screeching feedback? That would be positive feedback. Negative feedback would reduce your sound level.
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Thanks! Yes you are right. Sorry I used the wrong term. I thought Feedback like singing or sustaining is positiv and howling or screeching is negativ. But the term "negative Feedback" in Control engineering means actually the opposite Effect of what I ment. So I have annoying, howling, screeching POSITIV Feedback, which I personally consider as very, very NEGATIV for my guitar sound.

@ Snedecor: Thanks for YOUR Feedback. I think we both ment the same thing. It's good to know, that someone else knows the same Problem. I will look after the thinks you suggestet for getting rid of screeching.
 
Liquid22 said:
I have annoying, howling, screeching POSITIV Feedback, which I personally consider as very, very NEGATIV for my guitar sound.
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Sounds like the tweeter squeal Snedecor talked about. Try moving your headphones farther from your guitar, if that's possible.
 
This is magnetic feedback from the headphone speaker motors to the pickups. It is a particularly nasty type of feedback since it tends to be at high frequencies. The solutions are to turn down the phones, move away from the pickups or use different phones.
 
FractalAudio said:
This is magnetic feedback from the headphone speaker motors to the pickups. It is a particularly nasty type of feedback since it tends to be at high frequencies. The solutions are to turn down the phones, move away from the pickups or use different phones.
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Oh ok! Magnetic Feedback! Never heard of this before, but it makes sense - now that I know about it :D Thanks!

It's very interesting to imagine how the magnetic feld changes its form and intensity in connection with the tweaking of some parameters.
...and also interact especially with the covers of the LP-Pickups (Hellbat your right, I gonna try a different LP with the uncovered pickups when I'm home in two weeks)
Hellbat said:
If your pickups are metal covered it could be a resonance thing with the covers too.
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jeppekristoffer said:
What headphones is it that are causing this?
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I use AKG K701 Headphones


Tonight I will make some tests (changing Headphones and positions... again tweaking) and also upload the preset.
 
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