Bass traps for narrow corner space?

I had a block of rock wool, unused for a project for a friends studio, sitting in mine for weeks until I could get rid of it. Still in the plastic wrapper. It’s took me a couple of days to works out why the recordings made in that period sounded different. It was doing a great job absorbing as a membrane absorber!
I've recently turned my garage into a studio space and am working on acoustic treatment. Pretty much a newb, though I did build a space in a past house, I mostly just used cheap foam for echo dampening. I'm trying to do it"right"this time, but also on a budget. One area I am trying to figure out options for are two vertical corners where I only have about 9" of wall from the corner to a door and window frame on either side. Most corner bass traps are much bigger. I could find some cheap foam alternatives that would fit but I've read enough on here to know that's probably a bad idea.

One option I found was the 48"x12"x4" panels at but they seem to be meant for flat wall mounting, not corners. Was wondering if anyone had any experience or thoughts hanging them at 45º in the corner, even though the sides would not be flush. Or do you have any other suggestions? DIY is an option, I have enough tools and knowledge to be dangerous :) and probably could fashion some custom rock wool traps or something.

Another thought was to use the cheap foam in the corners but add 2" and 4" panels on the walls to help with better frequency modulation...

Any advice would be appreciated!

edit: added link to Acoustimac product
Yes do some d.i.y base traps cheap and easy to build and they work great! Check one out.


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