How to eliminate feedback from an acoustic guitar on stage

David Mellor

David Mellor is CEO and Course Director of Audio Masterclass. David has designed courses in audio education and training since 1986 and is the publisher and principal writer of

Thursday October 10, 2019

An Audio Masterclass website visitor has a problem amplifying his acoustic guitar on stage. WOOOOO....

A question from an Audio Masterclass website visitor...

"How can I eliminate feedback from an acoustic guitar in a live show? Also, sometimes I use a Shure SM57 to mic congas because my band has an acoustic African set up and it also sometimes give me feedback. What shall I do to get rid of the feedback?"

OK, this is two questions for the price of one. Firstly, the acoustic guitar...

Feedback happens when the sound from the loudspeakers gets back to the source microphone or instrument and is re-amplified, returning again at an even higher level. The familiar oscillation of feedback (howlround) is heard.

Feedback is a problem with microphones, electro-acoustic guitars with pickups (which I'll assume is what you are talking about), and can also be an issue with record turntables.

Concentrating on the electro-acoustic guitar, the first part of the solution is to make sure that the loudspeakers are pointing away from the guitar. If you do this, there is less sound to come back and be re-amplified.

Secondly, the guitar can be made more feedback resistant.

The body of an acoustic guitar is designed to resonate and transfer the energy of the strings to the air efficiently.

Unfortunately it will work very efficiently in the other direction too. It will take sound energy out of the air and transfer it to the strings.

So feedback is a likely occurrence, even when the signal is coming from the pickup and not from a microphone.

The solution therefore is to make the body of the guitar less efficient as a resonator.

One solution is to block up the sound hole. Proprietary sound hole blockers are available, but you could perhaps improvise your own.

This should be enough. If it isn't, then the guitar can be stuffed with damping material. I would recommend the same materials that are used for acoustic absorption in the studio, which you can easily search for online.

Now, the congas...

Damping won't work because you are using a microphone to pick up the acoustic sound of the congas.

The trick here is once again to point the loudspeakers away from the congas.

But also point the microphone away from the loudspeakers. Rearrange your set up so that this is possible.

Also, place the mic as close to the drums as you can. This might mean some compromise in sound quality, but it will give greater resistance against feedback.

Planet Waves sound hole cover...

Like, follow, and comment on this article at Facebook, Twitter, Reddit, Instagram or the social network of your choice.

Come on the Audio Masterclass Pro Home Studio MiniCourse - 60 great hints and tips to get your home recording studio MOVING

It's FREE!

Get It Now >>

Electric guitar - compress before the amp, or after?

How to choose the best key for your song

What is comb filtering? What does it sound like?

NEW: Audio crossfades come to Final Cut Pro X 10.4.9!

What is the difference between EQ and filters? *With Audio*

What difference will a preamp make to your recording?

Watch our video on linear phase filters and frequency response with the FabFilter Pro Q 2

Read our post on linear phase filters and frequency response with the Fabfilter Pro Q 2

Harmonic distortion with the Soundtoys Decapitator

What's the best height for studio monitors? Answer - Not too low!

What is the Red Book standard? Do I need to use it? Why?

Will floating point change the way we record?

Mixing: What is the 'Pedalboard Exception'?

The difference between mic level and line level

The problem with parallel compression that you didn't know you had. What it sounds like and how to fix it.

Compressing a snare drum to even out the level

What does parallel compression on vocals sound like?

How to automate tracks that have parallel compression

Why mono is better than stereo for recording vocals and dialogue

Clipping and compressing a drum recording to achieve an exciting sound texture

What can we learn about room acoustics from this image?

Can you hear the subtle effect of the knee control of the compressor? (With audio and video demonstrations)

What is the best studio microphone?

What is the Neve sound? (Using the Slate Digital FG-73)