Dealing with archtop feedback

[SierraTango]

"I've written about this many times. I added 2 sound posts to my '65 Kessel and it improved the sound. Gave it more note bloom, reduced the feedback and had ZERO negative effect on the acoustic sound or the amplified jazz tone."

The above quote is from Jack Zucker's post on this forum March,2016. Guess he had some success with soundposts at that time.

[Alter]

In my archtop the soundpost wasn't installed close to the bridge like they do in violins, but towards the middle of the body. It was installed by the luthier who built the guitar after i had it for a while and asked for a feedback solution. It got more "electric" sounding. Years after, i had the soundpost removed cause i don't use that guitar live much, and didn't notice any change in the action. There was no marks at the top when installed, but the tech that removed it did make a tiny dent on the back of the guitar, probably because there was a small bit of glue involved.

[SRNIN]

This works for me.

Cut/get a piece of black/gray foam, cheap insulation type (Lowes, Home Depot, etc), larger and slightly thicker than the F hole, maybe allow 3/4 inch larger on sides, 1/4-1/2 on thickness and stuff carefully into the sound hole. It will then spring back up making contact with the inside of the top and back holding it perfectly in place. Plus - it's gray/black, so it looks nice. There's no NC lacquer to deal with or binding on the inside.
For me: I did this on my ES125T (1.75 inside thickness) with a 2 inch square x 6-7 inch long piece. Works very well. Next up = thicker arch top, probably use 3x3 piece a little longer than the F hole itself.

[pingu]

This works for me.

Cut/get a piece of black/gray foam, cheap insulation type (Lowes, Home Depot, etc), larger and slightly thicker than the F hole, maybe allow 3/4 inch larger on sides, 1/4-1/2 on thickness and stuff carefully into the sound hole. It will then spring back up making contact with the inside of the top and back holding it perfectly in place. Plus - it's gray/black, so it looks nice. There's no NC lacquer to deal with or binding on the inside.
For me: I did this on my ES125T (1.75 inside thickness) with a 2 inch square x 6-7 inch long piece. Works very well. Next up = thicker arch top, probably use 3x3 piece a little longer than the F hole itself.

yes good idea
I did something fairly similar
worked for me too