Roger S. Messages: 15 Registered: September 2021 Location: Norway
Chancellor
This is how I applied damping material. I covered all sided with classic felt damping. This layer is just 7mm thick but has good effect.
Behind the woofer below the top brace there are two layers more. One sheet with the white stuff which is very airy, and classic foam type on top. So three layers in total behind woofer. Had this laying around from earlier projects, but I believe they will give a good combined effect.
Added some extra damping on one side as per Waynes description. A sheet with fiberglass will be added under the top brace as recommended.