Hometheater in a concrete basement (1 Viewer)

[gdb66]

Hi All,

A am an hometheater enthousiast from The Netherlands who has long dreamt of having a dedicated room for my home theater. Back in 2010 I had a new house build and included a design for a hometheater room in the basement. For the design I turned to Rives Audio.

Unfortunately the worldwide financial crises hit hard and my contractor got bankrupt leaving me with a huge financial hole. At the same time our income was in a freefall and dropped about 70%. With no help and no financial resources, I had to put what I had left into finishing the house.

Even though the rest of the house is still not finished, I now want to slowly start with the construction of the hometheater. When I studied the design of Rives Audio I had some questions. When I wanted to send a mail to Rives Audio, I found out they went out of business in 2015! I now how to find some answers by posting my story and my question in this forum.

The project

I have included the design by Rives Audio in this post (Page1.pdf and Page2.pdf). My basement is basically a huge concrete box with a sandstone wall to separate the stairs from the hometheater part. This is a current picture from inside the hometheater room where you can see the sandstone wall at the entrance, which will be the back of the hometheater.

The rest of it is just pure concrete. This is a picture of what will be the front of the home theater. In the ceiling there is the ventilation valves and on floor you can see the 300m of resilient channel I already bought.

Because everything is made of hard materials, the design includes making a drywall in front of the concrete and sandstone walls as well as the ceiling.

My first job will be to put these drywalls and ceiling in. My questions about this are:

1. Metal stud instead or wooden stud?
In the design it is mentioned mentioned only to use metal stud for the ceiling and the wall should be wooden stud. Is this for acoustical reasons, or mechanical ones? Since metal studs are available in various thicknesses (0.6mm-2.0mm) I believe the mechanical issues can be overcome. Metal stud is easier to install, is always straight and does not rot or twist over time.
If I was to switch to metal stud, I was thinking of 50mm width and 1.0mm thick steel. Only where there will be a soffit mounted and near the door, to use 2.0mm thick steel. Please advise on the impact of using metal studs for the wall on the design, instead of wooden studs.

2. Ceiling support
The ceiling height is currently 300cm, leaving only 15cm for floor and ceiling thickness to achieve 285cm finished ceiling height as mentioned on page 1 of the design. I estimate that the floor will be around 2cm, that leaves only 13cm for the ceiling.
The idea is to have the ceiling free of contact with the concrete. However, to cover the width of 500cm, that will require a metal stud of 12.5cm thick. Add to that the resilient channel and sheetrock and 0.5cm of space between the stud and the metal ceiling and you have a total thickness of 16.5cm, resulting in a finished height of 281.5cm instead of 285cm.
My guess is that that contact with the concrete results in more sound being transmitted to the rest of the house, where as altering the dimensions of the room will change the acoustics in the home theater itself. Is this correct?
I definitely do not want to change the acoustics in the home theater, so I went looking for an alternative. I think a suspended ceiling using hanger which are acoustically separated from the concrete ceiling. It is a bit difficult to explain, hence the picture below:

For the length of 500cm, I need 5 of these per stud. What do you think is better, to use this suspended ceiling and keep the original height, or to keep it contact free bit to lower the ceiling a few centimeters?

Those are my questions for now. It would be great to receive some answers, so I can finally start building!

 

[AV_Alexander]

At one point, early in Richard Bird Rives company existence, I interviewed with Richard fer an acoustical engineering n calibration specialist s position , n then later decided to pass all together. I've also engineered, designed n built several dedicated theaters over the years too., n have 20 years of retail , custom, n audio/videophile experience n years of Hiend equip sales. So I know a thing er two.
Without going completely through your posting, my first thought is you will most assuredly make quite a few key mistakes n have compromises , if you're planning an all out effort fer maximum return on acoustics and issolatiion both!
Lots to go wrong if you wish to issolate incoming and outgoing sound, both, while maintaining and achieving high fidelity well balanced sound!
I personally charge fer my services fer a living, as did Rives. In fact , u can prob contact Richard via Facebook , LinkedIn or twitter, n might get advice from him that' way if u want free???
I will say, that a room-within-room construction is what I'd shoot for, instead of mounting studs n resilient channel on concrete walls! Yes, much better all around if u build freestanding room inside that room! Strongly Consider to do it best.. then use channel n suspended drywall inside inner inside room, yes.
You're main problems going direction you described is bass transmission in n out of room, contact with concrete fer too much sound transmission at mid to low fequencies across the board, too much bass energy trapped in the room fer too much boom n long reverb in bass region (like boom box sound). Basically, if all that work, I'd want to do it right!
I've done many such projects early in my career that were done wrong! Better to learn from others mistakes, get consultant, n do it the most effective way!
Yes, consult the expert. Otherwise spend years n trial n error n big bucks learning the hard way. Period!