This is a link to an excellent video from Geoff at Discover Double Bass. It covers virtually everything about double bass feedback.
What are f-its? (pronounced effits)
If you've found this site, you're probably the proud owner of an expensive acoustic instrument, either an archtop jazz guitar, or a double bass, and as you've found out if you try to turn up the volume so that you can be heard above the rest of the band, you get horrendous feedback. Some feedback can be reduced by dialling out the offending frequency with your amplifier's graphic equaliser, or with the help of a pre amp with phase and notch filters, however this course of action can sometimes make your tone disagreeable.
So what is the solution to greatly improve double bass feedback or archtop guitar feedback? Well you could cover your f holes with gaffer tape as in the images to the left and right, (please click on any image to enlarge) but I think you'll agree you wouldn't want your instrument to look like this, or for the average pay you might expect from one gig, I could make you some custom made F hole guitar plugs, or f hole double bass plugs, which not only look great, they are also very easy to pop in and out as required. Although they don't eliminate it completely, they are a must-have aid in your anti feedback arsenal.
Sound hole covers
There are several companies that make round soundhole covers, Planet Waves' "screeching halt", and Harley Benton's "feedback buster" to name but two. These are cheap to buy because round sound holes are a fairly standard size, whereas acoustic f hole instruments are all different, and therefore have to be custom made.
After months of research, trialling different types of high density foam, glue and rubber, I've finally come up with what I consider to be the best materials available for manufacture. The finished items look great, are easy to fit, and will stay firmly in place when playing your hollow bodied guitar, or upright bass. They are hardly noticable from more than a few feet away. Please see the before and after pictures on the left and right.
A good way to see what difference f-its could make to your feedback problem, is to tape over your f-holes with a low tack masking tape; I wouldn't recommend using gaffer tape as some tapes are so strong they may damage the laquer of your instrument. You should notice a considerable difference, with very little effect to your amplified tone.
If you're interested in having a set of f-its made for your upright bass or archtop guitar, the first thing you'll need to do is send me a rubbing of your left f hole (when facing the instrument)
Please click on the box below.