Acoustically Challenged Room?

[cjgdiver]

I am in the pre-drywall stage of building a dedicated HT. After reading all the posts I could find I realized that my 6x walled room may have some Bass issues. While I am not too concerned about the far rear seating I do want the front seating to be perfect.

It is in a basement and most of the walls at this point are non movable.

I think I am attaching the room layout I also have a link for it. Any advice on how best to optimize the acoustics would be greatly appreciated. http://img83.imageshack.us/img83/6658/movieroom2gs.jpg


Panasonic AU900
Klipsch 35 series 7.1 , 12" sub
Onkyo 803
Oppo DVD

 

[bpape]

It's not that bad - it is unfortunate that you lost the 2 rear corners that would have been perfect for bass absorbers.

The first thing I'd do is close off that open doorway. You need to control the space.

Once you do that, move the seating up to reasonable positions. The first row is too far back and the second one is jammed against a wall and will never sound good.

For treatments, you'll need some broadband bass control - front corners will likely be required. Also consider the wall/ceiling corners. Plot your reflection points and treat them accordingly with 1-2" rigid fiberglass, mineral wool, or acoustical cotton - try to stay around the 3lb/cu ft density for these.

Lastly, you need to work out what the overall decay time in the room should be based on how you use it. How much more and where it goes will depend on if the room is pure HT, combination of HT and 2 channel music, etc.

 

[cjgdiver]

Thanks for the info.

The wife wants to leave the doorway open and hang some very thick curtains that can be open and shut. I give the doors another shot though. Am going to try and hunt down some 703 today.

One additional clarification, given the screen size how far foward would you recomend moving the first row? I read somewhere that the first row should be 2x the screen heigth. There was of coarse no referance to the the screen format.

Thanks again.

 

[cjgdiver]

Sorry one additional thought. Was looking at your web site and noticed the Acoustical Cotton. Do you think it could be sewn into the curtain in the doorway and would it help? Also plan on curtains on either side of the screen.

Thanks

 

[Joel DuBay]

Thanks for the info.

The wife wants to leave the doorway open and hang some very thick curtains that can be open and shut. I give the doors another shot though. Am going to try and hunt down some 703 today.

One additional clarification, given the screen size how far foward would you recomend moving the first row? I read somewhere that the first row should be 2x the screen heigth. There was of coarse no referance to the the screen format.

Thanks again.

Actually, ideal seating positions are at about 38% of the distance from your front wall. For lack of better term, you might call this the "sweetspot" and perhaps the baseline to judge your acoustics. Of course treating all areas and testing them for good acoustics is in order. This position should be your bass position for judging sound, not film. (gawd, I hope that makes sense)

Sewing an acoustical medium to the curtains will not hurt, and may help. But to truly begin controlling the room, those doors should be closed as my collegue mentioned above. Perhaps flowers and a nice dish of her favorites chocolates can win her over on the idea. (doesn't work for my wife though)


703 should be fairly easy to find, and there are many sources on the net where you can order and have it delivered to your door.

Sounds like a really fun project you have started. Good luck!

 

[bpape]

The cotton will be tough to work into the curtains - sorry. I have seen people use limp mass vinyl in the curtains to get at least some of the sound staying in the room. This isn't really an isolation thing but it does help a little bit with making the open doorway act somewhat like a wall.

As for seating position, what Joel says it quite correct. Generally 33% or 38% tend to be the best places. Normally, one would select the seating position and then buy an appropriately sized screen for that position, the PJ, budget, etc. Doing it backward like this tends to present some issues.

 

[ScottMayo]

I am in the pre-drywall stage of building a dedicated HT. After reading all the posts I could find I realized that my 6x walled room may have some Bass issues. While I am not too concerned about the far rear seating I do want the front seating to be perfect.

It won't be perfect. It will be ok for most movies. Making it perfect involves moving the seating forward, moving the front speakers away from the front wall, getting rid of those angled rear walls, and then treating the walls and possibly ceiling with absorption. All these things are more important than the doorway, though that doorway is going to be an issue. (If you hang several layers of VERY THICK curtain, you'll get the rough equivalent of an absorptive panel at that point, which might work out ok.)

 

[cjgdiver]

All,


This forum has been GREAT. I am thinking I can get doors on the door way (Going out to get flowers tonight ) Doubt I can do anything about the seating although although at least I now that My seat is in a pretty good spot to heck with the guests.

I guess I will just put 703 all over the place.

Thanks again for the input.

 

[bpape]

Plan out where you want the 703. You don't want it too dead.

 

[cjgdiver]

Its Finished

The pictures do not do it justice.

The Panasonic 9000 is spectacular. Put in 120" Carada screen, Klipsch 7.1 surround, Onkyo amp, seperate amp for Aurora shakers (worth every penny and then some). Custom acoustical pannels (followed instructions found on this site).

The Wife is now pushing for an HD DVD since she absolutely loves the HD cable feed.

Could not be happier with the end result. Thanks for all the advice.

 

[cjgdiver]

One more try with the Pictures

[URL=http://img134.imageshack.us/my.php?image=movie27re.jpg][/URL]

 

[cjgdiver]

Second Picture

[URL=http://img84.imageshack.us/my.php?image=movie22uu.jpg][/URL]

 

[cjgdiver]

3rd Picture

[URL=http://img53.imageshack.us/my.php?image=movie36px.jpg][/URL]

 

[cjgdiver]

4th Picture

[URL=http://img105.imageshack.us/my.php?image=movie47tc.jpg][/URL]

 

[cjgdiver]

The last pic. whew!

[URL=http://img53.imageshack.us/my.php?image=movie17bm.jpg][/URL]

 

[ScottMayo]

Looks gorgeous. One minor slap on the wrist - for what you put into that room, you should have gone with a professional acoustic planning service. You could go from great acoustics, to world-class, in that space. Actually, you probably still could, but guys like me drool over the chance to plan out spaces like that from the start.

Congratulations on a stunning room. Don't forget the popcorn maker.