[EdRo]

     O.K., guys, here's another rookie building an H/T room in his basement.
The room is 10' x 24',  with a 7' high "ceiling"(open floor joists). I have a Sony HD projector, an Onkyo 805 7.1 receiver, a blue ray for movies, and a cd player. Nothing fancy. I have a set of proto type Vapor Auroras for the front left and right, some surrounds that I built, and a sub box with 2, 12" subs and 2, 18" PRs in it; again, another home built unit, with a dedicated 1000 watt sub amp.
     The right wall is cement block, so I was planning to cover that wall from floor to ceiling with 5 inches of cellulose sheet, then cover that with sound transparent cloth. the same with the ceiling. The back wall would get a sky-line diffusor, and that back wall will be a "double" wall; with drywall, studs, then 10" of cellulose sheeting, then studs and drywall on the exterior. Some track lighting and wall sconces would round the room out. Oh, and a new cloth covered couch. The equipment will have its own dedicated line. I guess that's really important for HD projectors, too. Any suggestions, guys?

[Ethan Winer]

Any suggestions, guys?

It sounds like you're mostly on top of this, but the short articles below should help. This first one is mainly about home recording, but all the same principles apply to hi-fi and home theater too. The second will help with placements. Then follow up here with any questions.

Acoustic Basics
How To Set Up A Room

--Ethan

[EdRo]

Thanks for the great reads, Ethan! I plan on trying the 38% rule; that looks like a good place to start! I've been reading in my acoustics handbook that a good way to avoid bass nulls is to have a sub in the middle of each wall. I'd planned to break up my giant sub into two, anyway, so buying 2 more 12" subs and 2 more 18" PRs to make 4 separate boxes isn't that hard. I'm already halfway there! But, do I need 4 separate subs for a 10' x 24' x 7' room? I guess "need" is a relative thing. If my H/T benefits from effortless realistic effects when Tony Stark introduces his "Jericho", for instance, then the minimal expense is worth it! 

[EdRo]

Here's the site with the cellulose that I was going to try in my H/T room. This would go down the right wall (5.5" thick) floor to ceiling and be covered with a colored burlap. The ceiling joists (11" thick), then covered with black carpet to eliminate ceiling reflections. Doesn't this look like the GIK "green" material that they use?

http://cmsgreen.com/productlineup.html

[Ethan Winer]

I don't see any absorption data but it looks like it would work for acoustics.

--Ethan

[Bob in St. Louis]

Instead of running wires, run conduit instead. Run conduit everywhere you think you might want a wire someday.

Kilz2 happens to be the most neutral paint color for a DIY screen. It doesn't have a "push" on the visual spectrum.

[mcgsxr]

Having built up my basement HT this past winter, and with much input from the helpful members here, I agree that conduit for future additions or changes is your friend.  If you search the Home Theater circle, you will see the thread I used to document the process and progress throughout my build.

I ran conduit from my unfinished area (adjacent to the main HT space, and adjacent to the media closet) to 2 spots.  The first was the future possible PJ, and the other was to the main display location.

I did hardwire numerous wires as well, and left the conduit open for future use.

I ran multiple Cat 6e, coax, digital RCA, analog RCA, HDMI etc.

[EdRo]

I was so focused on the acoustics that I forgot about wiring!!! Thanks, guys!!!JEESH!!! 

[EdRo]

If I built the rear wall with a gentle curve, would that improve the overall sound, or would that just over-complicate treatment?

[EdRo]

Drywall will bend if the curve is not too severe. I could use plywood to make the curve. 2 stacked pieces of 3/4 ply would give me 1.5" to nail the studs to. The back wall being 10' across, I could bring the center out, say, 2'. Or back 2'.  Would convex or concave make for a better rear wall?

[jarcher]

As all have already said - conduit is your friend. Mine came into immediate use when I realized the crew had put the speaker wire in the wrong direction. Without conduit, correcting that would have been a nightmare. I've used both this blue corrugated plastic stuff from Home Depot and PVC for the "main lines" with more / thicker cabling. 

I use dual, used, entry level velodyne 10" subs forward firing at the front of my 30 x 15 approx HT room. I'm pretty satisfied with them for home theater at about $25o investment, but I'm not looking to shake the entire room and chairs. I don't have to even turn them up all the way to get the desired effect. IMHO I think what you've got will be more than enough to do the job, put experimenting with placement will be the key. Personally I would put them in enclosures and experiment by ear moving them around the front of the room. Using a real time analyzer app on an idevice / smartphone can help to try to work out if the placement is causing unwanted peaks. Small differences in angle / distance can produce significant differences.

The darker you can go with the room the better if your using a projector. Black on projected wall and ceiling if possible. I find even a bit of light leakage from outside can become noticeable, so try to make sure door and window treatments can suitably control light, particularly if your going to do daytime viewing. Epson does make some very bright projectors, but I've found that HT models from Sony and JVC really benefit from darker rooms.

I've never tried the painted wall route, but as high quality screens are available new or used at reasonable cost, I'd do that. Carada is a name thats generally respected at decent cost. I like fixed screens with black velvet borders for cost, simplicity and light control. Mine is about 96" and even if i could fit a larger one, I think that's a large enough size for me for my room size and viewing distance. 

I wouldn't over dampen the room with acoustic treatments, particularly ones you cant easily remove / uninstall. This is somewhat subjective as tastes vary, but for me the goal is not to make the room sound too dead (especially if you're also going to do music or music videos). Yes - it's good to do some diffraction / absorption at first reflection points so the sound is not too beamy etc. I mainly handle that with filled book cases.  But go easy on traps etc. In my 30 x 15 approx room two bass traps at the font corners was more than enough.

Lastly - but certainly not least - make sure you have some reasonably comfortable seating!  I tried to cheap out with ikea futons because they were inexpensive and looked good, only to find out they were really uncomfortable for more than 30 minutes. The specialist HT furniture manufactures are quite pricey, but good low cost options abound from places like Bobs Furniture.  I got my two HT leather power recliners new from HH Gregg delivered for $400 each. I think the padding could be denser / firmer, but everyone else loves them.

Best of luck to you. Having a dedicated HT room I think has to be one of any man's great joys. The spouse / GF etc will make noises about expensive "man caves", but much as they are reluctant to admit it, they love em just as much.

[mcgsxr]

http://www.audiocircle.com/index.php?topic=113851.0

Here is a link to the thread where I asked about what wiring to install prior to the drywall stage in my build.  There were excellent suggestions there, I won't try to document them all here.

If you have the time, being able to test subwoofer locations before the drywall goes up would be great.  You could then ensure there was an outlet near by, and run your cable of choice to that location also.

In my basement, I installed a subwoofer inside one of the walls.  There was a foundation bump out, so I framed it straight across, and used the space behind the wall for my DIY sub, and a small framed in cabinet.  There was no choosing where that space was, so I just went with it.  It is very good for HT.  It is admittedly not ideal for music, but I don't use that setup for music anyway.

I am sure you have a plan drawn up of the proposed space, I hand drew initially, then bought a $10 app for one of our iPads and used that.  It helped me plan the space well (in my case I was finishing the whole basement, and including a space for HT but shared with pool table etc), and was a dream to show the trades.  I would print out copies for them with markings specific to what I wanted from them.

Have fun, it is a long process, and it will have ups and downs, but weeks after it is done, it is fantastic to retreat to and relax.

[EdRo]

Thanks for all the good suggestions, guys! What does everyone think of my idea for the ceiling? I planned to put 5.5" cellulose panels between the floor joists, then cover that with a black carpet (med. shag) and my electric stapler! I wanted to cut down on the noise from the oak flooring coming from above. Its amazing the amount of noise a 3 and 5 year old can make! The black carpet stapled to the 2x10s overhead should help minimize screen reflection and help tame the old tile/cement floor. With some good tract lighting I think it will look great! Anyone have any thoughts about curving my back wall? Will that help?

[Big Red Machine]

Thanks for all the good suggestions, guys! What does everyone think of my idea for the ceiling? I planned to put 5.5" cellulose panels between the floor joists, then cover that with a black carpet (med. shag) and my electric stapler! I wanted to cut down on the noise from the oak flooring coming from above. Its amazing the amount of noise a 3 and 5 year old can make! The black carpet stapled to the 2x10s overhead should help minimize screen reflection and help tame the old tile/cement floor. With some good tract lighting I think it will look great! Anyone have any thoughts about curving my back wall? Will that help?

It won't help nearly enough.  My 2 channel room was double drywall on hat channel with green glue, etc and I still had high heel noise from the hardwood kitchen floor above.  You need mass in the immediate ceiling structure that is isolated (rubber mounts, etc.) from the room above.  Thin insulation and carpet is not going to do much for you.  Plus all the work of stapling that carpet up over your head to find out it doesn't do much for you will be exasperating.

[Ethan Winer]

I planned to put 5.5" cellulose panels between the floor joists, then cover that with a black carpet (med. shag) and my electric stapler!

Absorption on the ceiling will improve the sound in the room, but as Red said it won't do much (anything) to reduce noise from above.

--Ethan

[Bob in St. Louis]

Make the kids take of those (damn) hard soled shoes

[mcgsxr]

I have Roxul Safe n Sound between all the joists, and 1/2 inch drywall.

In terms of alleviating foot fall noise, it is nowhere near enough.  I can hear those monkeys wandering around up there regardless of my build.

That said, I knew that going in, and did what I did more to keep the sound IN the room.

I can listen louder than I would ever likely want to, and they cannot hear it up on the bedroom level.

I have no idea what a curved wall would do, sorry!

[JLM]

IMO proper room design involves:

1st: bigger is better

2nd: proper room dimensional proportions is essential (avoid cubes, try all 5:8 ratios)

3rd: isolate your room (insulated staggered stud interior walls, gauge metal furring strips between joists above and drywall, insulated exterior door, lined fiberglass ductwork, dedicated electrical)

4th: Multiple dispersed subwoofers

5th: Constant directivity speakers (for larger sweet spot)

6th: Treatments as needed (if you've followed the above, the need should be minimal as we're conditioned to listen in decent rooms and this should be far better than that)

7th: EQ used sparingly (for small sweet spots only)

[Tubo]

If I built the rear wall with a gentle curve, would that improve the overall sound, or would that just over-complicate treatment?

As an architect, I believe that building non-parallel surfaces (walls, ceilings, and floors) goes a long way towards eliminating standing waves, the source of uneven frequency response in a room. Coincidentally, John Marks of Stereophile just reviewed a book on the architecture of recording studios. The illustration for his piece shows the book open to a page with the floor plan of a recording studio with non-parallel walls.

So, yes, by all means build the curved wall, but make it convex. Concave will tend to focus the sound, like an acoustic lens—something you don't want! Convex will spread out the sound and help eliminate standing waves.

[rollo]

  If I were you I would hire a consultant to design the room around your speakers.  Ethan ? Brian ? The proportions of the room are key. Room treatment last if needed at all. Money well spent no guessing.


charles