I forgot to ask about the height of the room.Is there any recomended ratio between L/l/h?Thanks
Ohh, my room is just 7'2", I had to accomodate a ventilation shaft going right across the room. I wish i had at least 8 feet. 9 feet would have been great too. The height of the room was also very tight for me and had to be calculated very carefully considering the height of my feet on the sofa to make sure they werent in the way while watching, the height of the small step, the height of the center channel, the height of the curtain rod and the crest at the very top center.
And of course the height of the screen which had to include consideration for the offset of my projector. Because of my low ceilling, I had to be extra careful to fit everything just right. Ultimately, the height and not the width of my room dictated the size of my screen. If my room would have been a bit taller, i probably would have a 100"ish wide screen.
For room size, I read somewhere that 14x20x9 is a very good size for a music room. It seems about right althought I'm certainly not an expert. I know a smaller room than that would surely be a bit cramped for me. And a larger room would surely require an extra power amp to make it sound nice (altough i'm considering adding one in my room soon)
I know it a lot to digest, but believe me, take some time to plan your theater well. Since your are building brand new, you have the chance now to do something really nice. Like I read the other day: Rule number one: Measure twice, cut once. Ignoring this is a very expensive proposition.
I hope it helps. If you have other questions about the construction, do not hesitate to pm me.