Does anyone know of any alternative products to F-its?   I played a gig last week and basically had to cut all the low and mid-low end from the DB sound to prevent feedback on stage, meaning I struggled to be heard out front. The bass wasn't DI'd (which was probably an issue on its own, but owing to the nature of the gigs I play probably unavoidable in the short term).    I'd really like some f-hole covers like the F-its - https://www.f-itsfeedbackblockers.co.uk/