Room Treatment how to start

I have a garage I turned into a practice/recording studio. The room is 21x28x9 feet. The walls are concrete block. The cieling is one layer of dry wall and 10 inches of insulation. The floor is carpet with concrete under it. The garage door is aluminum and I put that aluminum foil-foam-aluminum foil insulation to keep the heat out and AC in. It didnt do anything for noise. There are two standard doors, one into the house, one outside. I am not worried about keeping sound in the room or out of the room as it is very quiet where I live except when I am home :). I am just concerned because the room has flutter and I know it needs treatment. Where do I start ? Do I need heavy treatment to have a good sounding room? Thanks!

Aloha and welcome to the forum,

I am not worried about keeping sound in the room or out of the room as it is very quiet where I live except when I am home Smile. I am just concerned because the room has flutter and I know it needs treatment. Where do I start ? Do I need heavy treatment to have a good sounding room?

Here's a good place to start: http://www.saecollege.de/reference_material/index.html and here: http://www.johnlsayers.com/HR/index1.htm Looking forward to your build. Hope this helps, Aloha 8)