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Combating unwanted resonance....Please help


bazm

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Had my LP vintage mahogony for a year now. Used 2 play it with a line 6 pod direct into our bands pa system. Only since getting a valve amp (peavey valveking) have i noticed a horrible low end feedback when playing at high gain settings..

I have an sg as well which is totally silent through the same amp. The feedback seems to stop if i grip the end of the headstock tightly leading me 2 believe that the natural resonance of the guitar is causing this?

I love the look and feel of the guitar but find it totally useless in live situations.

Any help/solution would be greatly appreciated...

Cheers guys.

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That's a tough one and, as much as I hate to say it, it sounds like it's that particular guitar. Different pieces of wood have natural tendencies to vibrate at different frequencies and, IMO, that's really what makes some guitars "better" than others. My suggestions are to 1) try turning down the bass control and/or gain on your amp or 2) as a last resort, consider buying a different guitar if that ones doesn't work for your style and sound.

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This issue is nothing new. I have read about this happening to a few other people. The feedback issue has become a problem with the chambered LPs when using higher gain. It makes total sense when you think about it. You have a semi hollow "chambered" guitar that lacks "f" holes which leaves no way for the sound to escape the guitar when the guitar resonates. Having said that, when the guitar resonates under high gain, the resonation builds up inside the chamber, causing feedback, because the sound has no where to go and is stuck inside the guitars chamber. You have a few options.... 1) don't use so much gain when playing your VM or 2) sell your VM and buy a Vintage Mahongany that isn't Chambered. Chambering started on October of 2006 so you might be able to track down a non chambered 2006 model or a 2005 model. Hope this helps.

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It's something that I experience with my 1991 Custom Shop LP Custom as well if I go too crazy with the gain or volume and that guitar has no chambering. But, when I was having the problem, I was playing in a metal band at high volume; with my current band, I'm using both less gain and volume and the guitar works fine.

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It's something that I experience with my 1991 Custom Shop LP Custom as well if I go too crazy with the gain or volume and that guitar has no chambering. But' date=' when I was having the problem, I was playing in a metal band at high volume; with my current band, I'm using both less gain and volume and the guitar works fine.

[/quote']

 

The chambering may not be the only cause for his feedback situation but I really do believe it is playing a big role. Non chambered guitars do tend to feedback at high volumes and at higher gain levels as well but I can guarantee you that the chambering is his guitar is not helping matters.

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I agree. For that matter, I think part of the problem might be caused by some sort of air pocket between the carved top and the body. My guitar might be old but it definitely sounds like there is some air under the top if not in the body.

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What you could try is moving up a string gauge. This will increase the tension on the neck, and just might reduce the resonant frequency causing the problem. You would probably need a minor tweak of the truss rod.

 

Talking of air pockets, here's a few.

 

weightrelief.jpg

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I was also thinking of the weight on the headstock idea, but if you have to grip the headstock pretty tight to stop the feedback, it might have to be some weight ! The ones I have seen are fairly small clamps (although if they were a material such as brass, they just might help). I think they are marketed at improving tone, but Paul Reed Smith was claiming a few years back, that he had improved tone by reducing headstock weight !

These ideas come and go... I would give the heavier strings a shot because the extra tension on neck (and body) might just shift the resonant frequency around - in fact I know it will...The question is to what extent.

Might be worth lowering the pickups slightly on the bass side - you've nothing to lose. I've seen many guitars where they have been dropped pretty low.

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Had my LP vintage mahogony for a year now. Used 2 play it with a line 6 pod direct into our bands pa system. Only since getting a valve amp (peavey valveking) have i noticed a horrible low end feedback when playing at high gain settings..

I have an sg as well which is totally silent through the same amp. The feedback seems to stop if i grip the end of the headstock tightly leading me 2 believe that the natural resonance of the guitar is causing this?

I love the look and feel of the guitar but find it totally useless in live situations.

Any help/solution would be greatly appreciated...

Cheers guys.

 

Sorry to say man, but read my topic ''Solid/swiss cheese Les Pauls vs chambered Les Pauls; useful info''.

 

The feedback problem you're having is mainly because of the chambered body and its natural resonance. You'll notice this in live situations where you have to play at high volumes. A chambered Les Paul isn't the perfect high gainer and it will never be, no matter what pickups you're using. That's why I got some P-94's for my own chambered LP Standard; they react very well and naturel to the chambered body and sound great for blues, lighter rock and rockabily.

 

The problem you're having is one of the biggest reasons that I don't like chambered Les Pauls as much as solid Les Pauls.

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Sorry to say man' date=' but read my topic ''Solid/swiss cheese Les Pauls vs chambered Les Pauls; useful info''.

 

The feedback problem you're having is mainly because of the chambered body and its natural resonance. You'll notice this in live situations where you have to play at high volumes. A chambered Les Paul isn't the perfect high gainer and it will never be, no matter what pickups you're using. That's why I got some P-94's for my own chambered LP Standard; they react very well and naturel to the chambered body and sound great for blues, lighter rock and rockabily.

 

The problem you're having is one of the biggest reasons that I don't like chambered Les Pauls as much as solid Les Pauls.[/quote']

 

Here is the thread he's referring to if anyone is interested in looking into this issue any further.......

 

http://forums.gibson.com/default.aspx?g=posts&t=11376

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Perhaps the chambering has nothing to do with it. If he has to grip the headstock, then it sounds to me like the problem is related to the neck, perhaps something to do with the trussrod. If he had to tighten up on the body to make it stop, then I might be more convinced about the chambering being the problem with this particular guitar.

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It's possible there could be a problem with the neck, but the action would be way out if there was a loose / broken truss rod. Hollow bodies have a reputation for feeding back at high gain / volume. When you see how close the routing comes to the major fixing points, this is weight-saving gone mad at the expense of structural rigidity. Wood fibres are strong along their length, and have excellent compression properties. Cut through these fibres, and there is a rapid loss of this strength. Imagine hacking through the vertical columns of a large building. I wouldn't want to be inside during an earthquake.

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IMHO I think it's just resonance of that particular guitar. My old SG would feedback on thelow E string at high gain, a buddy of mine has a LP studio and it feedsback on the D and my lead guitarists explorer feedsback on D also. He got rid of his VM due to feedback issues that he couldn't cure. My chambered classic gets played at high gain all the time at rehersal and it has no feedback issues.

 

Chambered LP aren't pressurized. Air escapes through the pup holes and cable jack. Each guitar is going to have a different resonance due to wood density, joint stability and weight.

 

Try changing string gauge up or down. If that doesn't work Seymour Duncan makes a product called FatFinger that can add weight to your headstock and help alter resonance. They are ugly but work.

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What rybass just wrote is probably the best explanation and possible solution.

 

How many times have talked about wood this and vintage that and old guitars, blah, blah, blah? Well, if there is any merit to old wood, then it probably has something to do with natural resonant frequencies, for better or worse.

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Yes, (as discussed earlier in the thread), different strings and adding mass to the headstock could shift the problem frequency. Worth mentioning again that hollowbody guitars are more prone to feedback than solids. It's been known for decades, and was the prime reason the (solid) Les Paul was created.

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This is definitely a neck resonance issue, and we have seen this discussed on these forums previously. I have had a similar problem with my SG that seems to be room dependant.

 

It is definitely not chambering as the root cause[-( . I second Rybass, as I play a chambered LP at very loud and high gain settings, and my SG had done it before, and it's not chambered.

 

Keep the same strings you have (for now) since you need to diagnose the issue. I would get some masking tape, and some dimes, nickels and quarters. Start by adding weight to the headstock, and see how heavy you need to go before the problem settles. You could very well find that it's not much weight at all. Add excess weight too, just to be sure that more weight won't find a new frequency to resonate.

 

From here you have a few choices: buy / make a steel truss rod cover; change the machine heads for klusons or something heavier than those vintage ones; Add a decoration to the headstock (or like you said a capo) made from silver / steel; leave the tape on...

 

Or sell it. But you may find a freaking sweet sounding guitar once you have adjusted this minor issue out of it...

 

(hollow body guitars feedback because of the sound hole)

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+1.

 

The guitar technology goes further and further, but that isn't necessarily a good thing. A good 20 year+ Les Paul Standard or Custom can't get any better than it is. There are lots of experiments with new technologies (which is nice), but for Les Pauls it's a BAD thing to my opinion. A Les Paul is still a Paul with a mahogany neck, mahogany body, maple cap and rose-

wood or ebony fretboard (with a few exceptions).

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I have had a similar problem with my SG that seems to be room dependant.

 

 

(hollow body guitars feedback because of the sound hole)

 

The SG neck / body joint is pretty flimsy compared to the LP. It's a big factor in why they sound different.

Hollow body guitars feedback because of the soundhole ? As mentioned previously, the chambered guitars have several soundholes. They just don't look like regular acoustic ones, or 'f' holes on archtop electrics.

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Have you tried using a heavier/lighter gauge set of strings?

 

Do you get the feedback with one pickup, or both.

 

You could try replacing the springs on your pickup height adjuster screws with rubber tubing.

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As mentioned previously' date=' the chambered guitars have several soundholes. They just don't look like regular acoustic ones, or 'f' holes on archtop electrics.[/quote']

 

Those sound holes are pretty much covered but air can move in and out so there is no pressure build up. Acoustics and semi hollow with f-holes or whatever feedback because of the huge open hole in the top which allows sound waves from the amp, room, whatever to bounce back and into the hole and cause unnatural vibrations in the top and strings which is fed into the pup causing the bad feedback. That's why these help eleminate the issue.

 

370344.jpg

 

I think there is a simpler answer than sell the guitar and buy a true solidbody b/c only a true solidbody won't feedback. Mainly b/c I have firsthand experience with a chambered LP not feeding back on high gain.

 

And sorry about the FF issue it's actually a groove tubes product:

Fat Finger

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This is probably a far fetched and impractical (probably very bad) idea. But, how about stuffing some of the accessible areas, such as the toggle switch area near the pickups, under the headstock plate where the truss rod screw is, etc. with some spray on insulation material or removal silicone rubber like stuff, in the hope of changing the resonance characteristics of the guitar? It seems like, in principle, it should work but I do not know whether this would work in practice.

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