If actual soundproofing is a must, and you are building anyway, consider constructing the "room within a room" concept.

The old school method was to "float" the interior room on top of trailer truck inner tubes.

The space between the outer room and inner room can be utilized for instrument storage, mic cabinet, etc. as well.

If you can find an old Hearing Test Booth, often found surplus, reassembling same on premises makes for a great and silent vocal or ac guitar booth. They even have connection panels already on the inside and outside.


--Mac