[Bumpy]

My piano finished, 2" thick, open baffles now show the scars of multiple DIY adjustments to the 8" mid and 2" tweeter. So I want to tidy it all up without scrapping the existing structure.

The existing baffle is 4ft tall by 18" wide. Into this I will cut a neat hole 10" wide by 14" tall.

My idea is to fix a new baffle about 10mm thick over this hole perhaps 14" wide by 18" tall. This dictates the size of the mid/tweeter baffle I need to buy

I want to be more creative than just use ply wood so I am looking for a fairly rigid tile/panel into which I can cut openings for the mid and tweeter. I would like this tile to be acoustically dead (like rubber) so the mid and tweeter are acoustically isolated from the bass and from each other.

The tile itself can be a bit bendy but not floppy

Any suggestions?

[Bumpy]

https://workplaceinteriorshop.co.uk/product/armstrong-tatra-board-bp958m-600-x-600mm-square-edge-ceiling-tiles/

This is the best fit I have found so far. They are ceiling tiles so they wont sag but classed as fibreboard with some level of acoustic adsorbtion.

Dont know how it cuts or if it leaves attractive clean edges.

[FullRangeMan]

The best panel format I have seen is the barrel format.
My preferred material is Baltic Birch plywood 30mm.
Secondly for a patch as this case would be transparent
acrylic 8 to 15mm, very inert to vibrations and lasts forever,
I have a salvaged 8mm transparent acrylic platform since
the early 1980s and its as good as new.