Now that the studio door threshold has been installed, pretty much all of the sound dampening treatments have been installed for the studio.  I couldn't wait to see how well the studio appeared to hold in sound from the inside.  The results were relieving, about what I was expecting, and less than ideal.

For the test, I set up my recording workstation and some monitors in the studio and turned everything to 11 - making it annoyingly loud on the inside.  Then I left the studio, closed the door and listened outside.

First, the relieving part - I couldn't hear a thing on the 2nd level of the house (two stories up).  Before the studio walls, you could hear anything from the basement on the 2nd floor.  I also couldn't hear anything through any of the supply or return vents of the HVAC ducts.  This was actually one of my biggest concerns early on in the project.  One of the main goals was to be able to play/mix music in the studio while the family sleeps, and I think that goal will be achieved - except for maybe drum tracking.

As for getting what I was expecting - the sound is soft and muffled but definitely audible right above the studio in the kitchen.  Considering how loud the music was inside the studio, the sound dampening is decent.  Our main living space is adjacent to the kitchen, and the sound is a little quieter there.  I'm being a bit too quick to judge since it was only one test, but I think you could get away with reading a book in the living room without getting annoyed by the sound. 

As for the living space in the basement, adjacent to the studio - the sound is still muffled and a lot quieter than inside the studio, but not as quiet as up in the kitchen.  The weakest part of the common wall that the studio shares with the living space is the door.  The wall itself seems to block out a lot of the sound and the music seemed to come out of the door itself.  In a separate test, I was inside the room and had Nikki talk outside of the room, and her voice sounded like it was coming right through the door - not a gap around the door, but the door itself.  This is a basic, solid-core door.

As for what is less-than-ideal - I'm not convinced I'll be able to play my drums without interrupting the household's ability to sleep or read a book.  This isn't necessarily unexpected, but a reality.  Nikki likes to watch movies, and we're planning on adding a wide screen TV to the basement living area adjacent to the studio.  If I'm playing drums and she's watching a movie, I'm not sure she'll be able to tolerate me.  It may all come down to improving that door.  All of these issues are things I can work around (e.g. only play drums at certain times, etc) but it's just not 100% ideal.  The fact is that I haven't even set up my drums yet to see.  Maybe these conclusions are a bit premature. 

One thing my test didn't cover was sound leaking to the outside of the house.  The studio has a window, and I'm positive that the outside noise is audible to neighbors.  Our last neighbors were very tolerable and didn't seem to notice that much, but we have new neighbors who haven't really ever heard me play drums yet.  A sound dampening "plug" to fit in the window cavity (from the inside) is something I have in mind to address that in the future.

This basement has been about a 4.5 year project.  Before that, I researched sound dampening construction for about two years.  What have I learned through the whole process?  A lot.  For one, everything you think you know about studio construction and "sound proofing" is wrong: http://kindohm.com/archive/2006/10/25/Advicefordo-it-yourselfhomestudioconstruction.aspx.  Make sure you pick up a copy of Home Recording Studio: Build it Like the Pros by Rod Gervais.  It costs less than $30 on Amazon.com and you'll save magnitudes more on your studio if you buy it. 

So far, I'm pleased with the results.  If I had to make two improvements, it'd be the door and the ceiling - as both seem to cause the greatest issues with sound transmission.  However in my case I don't know that I could make those improvements given budget and space constraints.  I think I probably built the best studio I could given what I had to work with. 

We'll see how things go in the next year.  I'm sure I'll have either a different or stronger opinion after getting a chance to break in the studio space!  For now, I still have a basement project to finish and furnish.