Fighting Feedback on Hollow and Semi Hollow Body Guitars

The ladies are always asking for feedback...  just not this kind!

Alright, we’re back at it today continuing with yesterday’s article all about hollow and semi hollow body guitars and their propensity towards feedback. Now yesterday we delved into exactly what kind of feedback affects these guitars as well as the factors that contribute towards it. For those of you who missed it, you can check out part one of our feature on acoustic feedback and semi/full hollow body guitars right here.  Alright, so we learned that with acoustic feedback – the kind of feedback immune to solid body guitars – happens when a soundwave strikes the hollowed inside of the guitar’s body, causing it to resonate. The resonating body then gets the strings vibrating, which are picked up by the pickups, which is amplified by the amplifier, which causes more soundwaves coming from the amp to strike the body again, causing it to resonate... again. Yep – a weird kind of perpetual loop indeed. As far as factors that contribute towards this kind of feedback, it comes down to three things:

1. The bigger and louder the amp, the more susceptible you’ll be to acoustic feedback

2. The more overdriven your tone is, the more susceptible you’ll be to acoustic feedback

3. The closer you are to your amp, the more susceptible you’ll be to acoustic feedback

It’s not up there on my three pronged list but facing your guitar towards the amp is a huge no since it pretty much sends a ton of waves inside that body. Alright, so now that we know exactly what causes this kind of feedback we can begin discussing some tips and techniques used to combat it. Sure, you can always grab yourself a solid body but I completely understand the fact that some people simply like the look and feel of a nice semi or hollow body guitar – not to mention the very warm and resonating acoustic tones that come with those guitars.


Fighting Back Feedback!

Acoustic feedback in hollow and semi hollow body guitars is nothing new – it’s actually been known about ever since their creation. Back then, it wasn’t a huge deal as most guitarists simply weren’t using 100+ watt amplifiers, overdriven tones and maxed out settings – each of which contribute towards the problem. Nowadays, each of those things seem to be prerequisites for most styles of rock, so it makes sense that manufacturers would try their best to come up with new designs that would help alleviate acoustic feedback – and that they did! The first thing was adding a center block inside the body of the guitar. This drastically reduced the resonance of the inside of the guitar which cut back on the feedback; the only problem was that this affected the tone of the guitar as well. Manufacturers weren’t the only ones fighting hollow body feedback either.

That Old 'Foam in the Guitar' Trick

A trick that began popping up with plenty of famous hollow body guitarists was the act of stuffing the inside of the guitar. B.B. King is said to have used newspaper inside his Gibson ES-335 to combat feedback. Jack White was known for stuffing foam into his old Kay hollow body. Different material but the main goal remained the same; reducing the resonance of the guitar. In fact, if reducing the resonance of the guitar is your aim, even a shirt or a towel should do the trick. The only problem; it reduces the resonance, ergo, it changes the tone. Yes, reducing the resonance is a double edged sword if keeping the tonal characteristics of your hollow body is the main priority. If that’s not your main priority, then you can give this trick a try as if should definitely alleviate the problem, especially if playing with loud overdrive is a must.

The Other Kind of Plugs

There is also some rumors going around plenty of forums that George Benson was known to tape up the f-holes on his hollow body. While I’m not saying that Benson did or didn’t do this particular trick, I would be wary of the effectiveness of such a solution. Knowing what we know about what causes acoustic feedback, simply taping up the f-holes might slightly alleviate the problem, but it will be a slim change at best since the sound waves inside the hollowed chamber of the guitar will still be bouncing around (they will just get very slightly slowed down by having to go through the tape first). Also, taping up the f-holes might cause the paint job to peel away – not to mention it doesn’t exactly scream professional – so coupling that with the technique’s relative ineffectiveness towards combating feedback, I would just try something else, something thicker, something that fits perfectly… like an f-hole plug! Essentially the same idea as taping up the holes only an actual plug is thicker which makes it much better at keeping the sound waves away than simple tape. Even then, while using f-hole plugs will give you a noticeable amount of feedback reduction, from my own experience, they still don’t drastically eliminate it when playing particularly loud and overdriven. Clean on the other hand, they work perfect, but clean settings aren’t as prone to feedback in the first place. Anyways, f-hole plugs; pretty good, but you should do this along with another technique for better results.  


Noise Free is the Way to Be

If stuffing shirts inside your guitar or getting some f-hole plugs is not your thing, have you ever considered using a noise suppressor? There will be a lot of people out there who will probably tell you something like, “Noise suppressors? Those things absolutely kill tone! Don’t use them!” True, by their very nature they can change tone. Noise suppressors eliminate noise by cutting off certain parts of the signal where noise is most likely to reside, the only problem is, unless you know how to work them (which isn’t hard at all but does require you to know basic music jargon such as dbs and such) you might end up setting up your suppressor so that it does kill your tone. If you take this route, you will only need to set up your noise suppressor using very minimal settings – just enough so that feedback is reduced and your tone is 100% intact. You might have to fine tune these very slight settings by ear like I usually do, but it’s nowhere near as difficult a task as it might sound.


(A noise suppressor like this Rocktron Silencer pedal might be just what you needed! Only $119.00!)


And finally, the easiest, cheapest, most used and quite possibly most effective technique used in combating acoustic feedback is… moving around a bit! Yes, simply standing a certain distance away from your amplifier along with having your back to the amplifier is the quickest cure out there! In fact, just not facing the guitar towards the amp will reduce the tendency for feedback more than anything else I can recommend but remember that being away from your amp is also necessary for full feedback control as well as how much overdrive is being used. As for how far you should be standing, it depends on those three things mentioned at the beginning of our article. In the end, you should definitely try out a few of these techniques if you ever find yourself in a situation that calls for some feedback control. Or… you can always buy a solid body.

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