Thanks, Martykl. 4 subwoofers is definitely something I am keen to consider later. Also, I am in Christchurch / New Zealand; transport is not negligible.
Here is a new version of my music room plan. This one is fullsized. The shelves at the back are for CD storage only
Here is a new version of my music room plan. This one is fullsized. The shelves at the back are for CD storage only