There are countless situations in which acoustic guitars are played live or amplified, so it's beyond the scope of our expertise to go into each one of these. So Firstly, we recommend you educate yourself on the factors that contribute to feedback, and some of the most common methods to deal with them. This will help you tremendously for future live events, regardless of the guitar you're using. Here are a few guides we've found useful:
Click here for Acoustic Guitar Magazine's Guide (most thorough) Click here for Thomann's Guide Click here for Reverb's Guide
There are numerous videos on YouTube as well, so you can do a simple search on "guitar feedback" and see dozens of great videos as well.
For a quick and affordable fix for feedback on an acoustic guitar, you can try a sound hole cover - aka "feedback buster." This is what we recommend most, and sooner or later you'll come into a "feedbacky" environment and this will save a ton of time and headache.
For a more versatile but more expensive approach, you can try a preamp with a phase switch and notch filter included. This gives more customization for tone, and lets you dial out the offending frequencies.
For our carbon fiber OF660 guitars and OB660 basses, you can also try our YKG004 sound hole cover that's custom designed for these sound holes. This is the simplest and most reliable solution for dealing with feedback on these models. IMPORTANT: This sound hole cover only works with the second generation of OF660 - see description for details.
If you're using our EP001 upgradeable passive piezo pickup, you can try upgrading to our EPS001-15K dual source active module for our OF660 and OB660 sound holes, or the EPS001-05K module for traditional sound holes. These include a phase button and the ability to pan between two pickups as well as adjust treble and bass volume. Note that this is a powered unit.
NOTES: 1. You must use the newer upgradeable model that has a removable 2mm connector from the piezo elements to the pickup jack. 2. The EPS001-05K and EPS001-15K modules are not complete pickups, they require the EP001K, EP004K, or other passive piezo pickup to be previously installed or to be purchased and installed at the same time.