Is a hardscape sub as hidden as a burial sub?

No. Burial disappears. Hardscape is designed to sit in structure when burial is not possible.

UltraScape is specified to grow to two subs. Spec the second as burial or hardscape from the same listening test, not from a second brand.

Hardscape vs burial subwoofer

Do not force a burial can under a finished patio. The hardscape 12-inch exists for that constraint. Do not leave a large yard on satellites alone because excavation is inconvenient — that is when the hardscape SKU earns its keep.