I want to hit 115-120db, if not louder, with extreme clarity. Obviously that will not be consistent listening levels, but I want to know that it's there when I want it. I had a car system that was that loud and it was ridiculous! I have yet to hear a home system to rival what was in my car. Maybe it is not achievable within a working/family man's budget?
Dude,
I don't know if you can actually appreciate what 120db is bringing to the table, but, if you can achieve it and enjoy it, more power to you (I love a good pun). You ask if you can do it at home having done it in a car. A car is a sealed chamber albeit a small one too. I have seen videos of people inside such cars when they fire up SPL levels like you are talking about. Their hair freakin flies all over everywhere from the sound pressure. Its awesome to watch but I'm not sure more than a few moments inside would be any fun.
Like the other AH posters have indicated, it takes an insane amount of power and limited distances to hit 120db in a room. I think its achievable but you may not have the right speakers to get it done. Like
@Pogre said, you may need to go with something better suited to the task. Amplification you could simply rack n stack like a big stack of pro series amps to manage the cost. But you'd have to take care with the speakers you chose so that as you drive them that hard you don't just melt them. That would mean to me lots of drivers each coupled to the power source.
Again, I don't know if the final result, 120db at lets say 6 to 8 feet from the speakers, is really worth the cost. But, hey its your dream so if you have the money and the desire, I'd love to see what it looks like. I'm not sure I'd want to listen in at 120db because my hearing is already not what it used to be. I need to keep my ears together for the rest of my audio journeys.
Have fun ! This sounds like crazy fun. But have fun.