Hi! Playing through Kemper power stage, seymour duncan powerstage 700 and two kabinets, there is a low "bass" frequency feedback rising up whenever I stop playing.
I noticed if the volume is lowered then it doesn't happen so often. I don't play too loud, but more volume was necessary. The point is, it wasn't too loud and there should be no low frequencies feedback.
The low cut output frequencies are already cut to 100Hz (though maybe it doesn't work for the monitor output and only works for the main output, now I'm not sure about it).
Really don't understand why that low feedback happens, never before happened. Any help will be truly appreciated.