There are 2 types of sound transmission, air born and structure born. Air born can be stopped mostly by mass alone. Structure born requires decoupling, which means a mass layer, air gap (or other low density layer), followed by another mass layer. Recording studio doors have mass layers and an air gap. They are usually very thick (3" or better).
Albert pointed out doing 2 doors with a significant air gap. This is also done in studios and is called an air lock. It is a greater air gap and thus is even more effective.
Last, I'll point out that STCs often quoted for things like this are often useless. STC (sound transmission coefficient) is for 125 Hz. Usually the problem frequencies are much lower, like around 50 Hz and are structure born.
Now the door probably is the biggest problem you have, but there's no point in buying a very expensive studio door if your walls are single layer sheetrock and offer little sound isolation. Sound isolation works like the old addage "a chain is only as strong as it's weakest link."
Probably the first thing to do is determine what type of sound transmission is the problem and go from there.
Here's a linke to our resource page. There is an article we wrote on sound isolation that might be of help.
Rives Resource Page
Albert pointed out doing 2 doors with a significant air gap. This is also done in studios and is called an air lock. It is a greater air gap and thus is even more effective.
Last, I'll point out that STCs often quoted for things like this are often useless. STC (sound transmission coefficient) is for 125 Hz. Usually the problem frequencies are much lower, like around 50 Hz and are structure born.
Now the door probably is the biggest problem you have, but there's no point in buying a very expensive studio door if your walls are single layer sheetrock and offer little sound isolation. Sound isolation works like the old addage "a chain is only as strong as it's weakest link."
Probably the first thing to do is determine what type of sound transmission is the problem and go from there.
Here's a linke to our resource page. There is an article we wrote on sound isolation that might be of help.
Rives Resource Page