Ultra FBR2 Feedback Buster for Acoustic Guitars

(10 customer reviews)


  • Plugs Right into the Soundhole
  • Fits Soundholes 3 7/8″-4″
  • Model# FBR2
  • Country of Origin: Taiwan, Province Of China


Let us put it to you straight. The squeals of feedback WILL ruin your show if you don’t find a way to get them under control. That’s where the Acoustic Feedback Buster comes in. It plugs right into your sound hole so your acoustic guitar’s internal microphone isn’t picking up your stage monitor feed and starting that nasty feedback loop. The Acoustic Feedback Buster fits into just about every acoustic guitar -if yours has a soundhole from 3 7/8″-4″ in diameter, you’ll be good to go.

Additional information

Weight 2.82 kg
Dimensions 4 × 4 × 0.5 cm
Product Dimensions

4 x 4 x 0.5 inches

Item Weight

2.82 ounces



Domestic Shipping

Item can be shipped within U.S.

International Shipping

This item can be shipped to select countries outside of the U.S. Learn More

Country of Origin


Item model number


Assembly Required


Number of Pieces


Warranty Description

See manufacturer.

Batteries Required




10 reviews for Ultra FBR2 Feedback Buster for Acoustic Guitars

  1. swenpaylay

    Works for most Gibson Acoustics with a little modificationSize is perfect for my Gibson J45. However, it doesnt sit flush with the controls in the soundhole. I used a steak knife to slice off about a half inch on that side of the Feedback buster so i can access the controls and it sits flush.Be careful when you put these in. They can easily mar the nitro finish and put pressure on the top wood. It should get the job done though. I likely won’t use it very often as I don’t really have issues with feedback, but I’ll keep it in my case just in case.If you are buying this as a way to quiet your guitar for practice, it doesn’t really do that. It does cut mid and bass a bit and makes the guitar sound smaller but the overall volume is the same. I suggest learning how to finger pick instead.

  2. chris brown

    It works!It works, I popped it in when using the acoustic through the speakers and it totally stopped the feedback. I tried it with an acoustic DI straight into my FRFR speakers and through my fractal separately. Even low shelving eq wouldn’t stop the feedback if I leaned over for an adjustment, but this actually helped. I tried clean and distorted sounds and it really helped. Of course on super high gain it might give you problems, but a lot of acoustic is a bit less distorted and experimental than what I was trying, so it should help in live situations regardless. It’s a bit of a tight fit on my low end Ibanez acoustic,Aw-50 I believe, sits flat and unobtrusive, check your soundhole measurements, but it works well and got here quickly.

  3. Bugs

    Modify It for 3-7/8″ Sound HoleI have two guitars with a 3-7/8″ and hoped that this would drop in without too much fussing or string loosening. It is just thick enough to fit under the strings while they are all carefully lifted up under full tension. However, just like the Dunlop Suppressor, it is exactly 4.05″ and takes too much force, then distorts with a 3-7/8″ hole. It is easily sanded to 3.90 with a Dremel sanding drum to snug into a 3-7/8 (3.875)” sound hole so that it takes no un-nerving force to install. Would appreciate it if they were made with a 3-7/8″ groove right below the flange so they would fit the advertised diameter range and still seal well enough to do the job. 5 stars if it did.

  4. Miami

    Fit perfectGreat tool for guita

  5. sunesis

    Works to beat feedbackThis does a good job of stopping feedback for AE guitars, and I have been using it to soften the sound and reduce the “boom” when recording my acoustic through a microphone. Be aware that it takes some doing to get in and out of the soundhole, and when installing it, I was a little concerned that I might damage my Martin guitar. So be careful with it. Otherwise, it does what it says.

  6. Mr335

    Does what is meant to do! Bust feedback!Product works great. As with many feedback busters installation can be a little slow due to the rubber gliding on the guitar and catching on the strings but it normally doesn’t take longer than 10-20 seconds. I have experienced no issues with feedback when this is installed. However, I was hoping to also get a little more of sound cancellation from my acoustic out of it but some sound still comes through. (That is just my preference with acoustic instruments that are plugged in, I like to hear them strictly from the monitors and not multiple places, ie monitors and instrument.) Overall, great seller, service and product.

  7. Edward Alcobia

    Perfect taylor fitGreat job

  8. MickeyG

    Lives up to its nameFor years I avoided using one of my favorite guitars in live performance because of chronic feedback problems. I had seen the Feedback Buster used by others, but just never got around to buying one. I can’t believe I have now “fixed” my $1,000+ guitar for less than $10.This product is designed and manufactured by Kaman Music Products, a sister company of Ovation. So it’s a perfect, snug fit for my 1980s-era Ovation Legend, including the curved cutout to fit around the end of the fingerboard. I would expect it to also fit any acoustic-electric guitar with a standard size soundhole.The soft rubber-like material would be easy enough to cut if minor customizing was needed. But for the price, it’s definitely worth a try. But if you’re looking for a perfect Ovation fit, as the saying goes, “don’t settle for cheap immitations.”

  9. ginwc

    It DependsIt is made of very thick rubber and I know it must work well because I see them being used by many players. I read that some users had trimmed theirs just to get it in the sound hole. I had to cut it to make the top flat instead of rounded because there is a pickup at the end of the fretboard on my guitar that overlaps the sound hole. That allowed me to get it in the hole but it leaves a small open space and I still get feedback. It’s the low E string that causes it. Keeping the bass level way down on the guitar and the amp – or using a lighter weight low E can stop it. Not ideal if you want a rich bass sound. Looking for a feedback buster that will work around the neck pickup.

  10. Bill Lundgren

    The Feedback Buster Does Indeed Bust Feedback – Perfectly!I used this for a gig the same day it was delivered. My guitar didn’t feedback at all. My acoustic duo-mate’s was howlin’ like crazy. It works. And I was surprised by the thickness of the rubber of which it is made. Good stuff. And very reasonable price. I’ll be getting a second one for “the other guy.” The real test will be this weekend in a venue where we routinely have the most difficulty. 3rd fret, 5th string (“C”) is THE problem. We’ll see…

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