Really simple Lowboy, the box was approx. 18″x18″ enough to get my melodica and hands in you can still see the melodica, but if you want to completely close your view just place a towel over the top and let it drape over loosely. It is not the cone of silence it just reduces the over all loudness of the melodica. Do this in a room with the door close and it works great. I place the box on a folding table and sat in a folding chair. No rocket science here. I used cheap foam I purchased at a material store, the one I purchased was 1 1/2 thick used for upholstery. Box was free and foam cost about $8 bucks I had some glue so I was only out the foam.
There you go.
Monsters of Melodica