Quote:
Originally Posted by
Audixium 
How is the isolation from the first floor? Can you crank the amps and hear anything upstairs? I know my son is going to want to do that (and, um, me too

).
Thanks for the comments.
The soundproofing has actually exceeded my expectations.
The basement area outside that room is slate tile floors, with an open staircase up to the main floor that comes right up between our family room and kitchen. A formal living room is right above the theater. I am often down there blasting away at a fairly uncomfortable level (not ear bleed levels, but too loud for most folks) and when I walk upstairs to the family room, kitchen or living room and ask how it sounded, my family looks at me with blank stares and says "how did what sound?" Some sound leaks out around the area of the door, as that is expectedly a weak link, but not enough to really carry up the stairs. I left room to add a second door if needed, but so far I am happy without it. The HVAC return is also a weak link (still some work to do there), but luckily it runs straight into the mechanical room and I am not experiencing any noticeable flanking (better lucky than good on that one

).
The only time we hear anything upstairs is when someone in the theater is playing material with really heavy, low bass, such as Transformers, and only then if at an extreme level. In the living room (and only in the living room) you can hear faint rumbles of bass when the big explosions happen, etc. In fairness, I don't have a great sub. I am sure I'd hear a bit more rumbling if I had a big-time sub shaking that room.
All that said, I routinely blast music or movies after the family has gone to bed (two floors above) and there is ZERO sound getting up to that floor, rumble or otherwise. That was my main goal when I did the soundproofing--being able to play music at night and not disturb anyone.
Oh, and it is dead quiet in the room when I shut the door, something I hadn't appreciated as a benefit when I was planning.
I highly recommend making the effort of soundproofing. Mine isn't perfect, but it is quite good.