Help needed: Room Treatments on the cheap?

[kexodusc]

Helping my cousin set up his new home theater, a very nice 7.1 system consisting of the B&W 700 series driven by a NAD T763 receiver (if I've got the model right) with a Hsu Research VTF 3 sub!!! He won't tell me what he paid for everything.

We've got everything set up but the finishing touches...room treatments. Looking for ideas on how to tame the sound...

I've got to admit that I'm probably sitting to the outside of the bell curve when it comes to room treatments, so maybe I can kill two birds with one stone here and learn something to apply to my own room.

Here goes:
The room is 19' X 11.5'. (8 ft ceiling with that 80's spackling stuff on it). At present time he's got a (sigh) concrete floor with an area rug. This summer he plans to get carpeting or that wood laminate stuff that's popular, and he'll probably add some throw rugs later.
Mostly bare walls except for some bookshelfs and a table thing on the sides and back.

Surprisingly, the room doesn't sound all that bad right now...but we're pretty sure it could be better. He's already got a BFD to EQ his subwoofer and bass traps don't seem to be needed right now.

Attached is blueprint below...I think we're more worried absorbing or even diffusing reflections and taking care of behind the front speakers for now, it is a bit lively down there. Not sure the bookshelf and table are doing the trick.

I know some of you room acoustic guru's have come up with your own solutions. Being the parsimonious "thrift-o-philes" that we are (hey, he's family, what did you expect) we'd like to hear some inexpensive solutions before ordering a few hundred worth of acoustic panels.

Any ideas?

[topspeed]

Disclaimer: My knowlege on this topic isn't close to Wooch's, Sir T's, Doc Greene, or E-stats on this subject.

You could try using higher bookshelves with the book's spines unevenly spaced, tall plants, tapestry or pictures at the point of first order reflections. It doesn't sound like you need corner traps at this point and believe it or not, that horrible looking acoustic cottage cheese on the ceiling might be a good thing! Those concrete floors certainly aren't helping, but that situation is temporary anyway.

You might pm'ing Sir T as I think he installs this stuff.

[kexodusc]

Disclaimer: My knowlege on this topic isn't close to Wooch's, Sir T's, Doc Greene, or E-stats on this subject.

You could try using higher bookshelves with the book's spines unevenly spaced, tall plants, tapestry or pictures at the point of first order reflections. It doesn't sound like you need corner traps at this point and believe it or not, that horrible looking acoustic cottage cheese on the ceiling might be a good thing! Those concrete floors certainly aren't helping, but that situation is temporary anyway.

You might pm'ing Sir T as I think he installs this stuff.

Thanks topspeed, he's got a few pictures he can hang but I guess we're waiting to hear all options first. I don't know about other bookshelfs, furniture etc. I had already told him to cram more stuff in there. Never thought of plants, that might be an option.

The real trick is to find a balance between effective treatments and satisfying the WAF.

[Woochifer]

Some general rules of thumb are to absorb as much as possible along the front wall behind the speakers, absorb at the sound reflection point along the side wall, and diffuse along the back wall. The whole point of all this is the minimize echoes as much as possible. Rooms that echo a lot will extend out the decay time, and hard reflective surfaces contribute to this. Absorptive surfaces reduce the decay time, which reduces the echoes. Diffusion helps to scatter the reflected sound waves so that they are not perceived as part of the same event as the direct sound.

A concrete floor reverberates a lot, and a nice thick rug does help to minimize the floor's contribution. That spackled ceiling that you talk about, is that the same as an acoustic ceiling? (with the rough pebbley texture) If so, those actually work very well at taming the echoes in a room. Unfortunately, they are ugly and interior decorators have taken it upon themselves to convince homeowners that acoustic ceilings are evil and that they absolutely must pay the big bucks to remove it (even though they serve a very functional purpose by reducing the noise level in the house, especially houses with kids).

Bookshelves along the side are good because they also help to break up the first reflections. But, if they're overly enclosed, then they can create reverb of their own. Typically, the recommendations I've seen are to identify the sound reflection points and put absorbing panels there.

If possible, the bookcases might be best served at the back of the room. Guidelines I've read generally say that you don't want to overly dampen the back of the room. You want to retain that part of the reflected sound so that it creates a diffuse ambient effect.

How much the room treatments cost depend on 1) how much they are tuned to specific frequencies or applications (or even how well their sound properties are documented), and 2) the aesthetics. You want something that looks refined and can fit into home decor, you need to either pay the extra $$$ or get creative at the DIY end.

If you're willing to go with the inexpensive but butt ugly approach, then you can just unfurl some fiberglas insulation and wrap it in fabric to keep the fibers from scattering. Or start like I did and grab a $16 box of acoustic ceiling panels, and just line them up behind the speakers. Another option is to glue some acoustic foam pieces behind the speakers. DO NOT use packing foam! Acoustic foam is typically fire resistant, whereas packing foam is highly flammable -- the members of Great White will tell you that this unfortunately is true.

Some of the more creative approaches include getting some rigid fiberglas boards and putting frames around them. I plan to try something similar soon to replace the acoustic ceiling tiles that I currently use (those are wrapped in fabric and suspended off of a picture molding throughout my room). My current room treatment setup is not optimal because aesthetic compromises forced me to go with only three panels up front. I used to use six of them, and the imaging was noticeably tighter when the acoustic panels fully covered the wall from end to end. Compared to acoustic ceiling panel, fiberglas boards have greater absorption, particular in the highs.

Owens Corning seems to have new fiberglas products that are precoated with a fabric layer. This could make DIY acoustic panels much simpler to produce. Anyway, Hometheaterhifi recently had a great overview of room treatment products that you should look at. My response on a prior thread has the link.

http://forums.audioreview.com/showthread.php?t=9996

[kexodusc]

Read the link already Wooch, lots of ideas there! You've guys have given us a place to start...off to the hardware store Saturday morning. I would have aimed at taking care of everything BUT behind the speakers...time to get creative...

I like the acoustic ceiling tile option for my room, the walls are bare and I think some fabric could spiff it up some...dunno if my cousin's wife will approve, we'll see.

Thanks guys.