Absorption or diffusion????


Hi all, I've been adding some acoustical treatment to my room the last couple of weeks. I am waiting for some of the Auralex Tfusors and Metrofusors which are on order from my local Sam Ash. I have implemented pieces of their Studiofoam 2" pyramids, wedgies and Lenrd Bass traps for absorption. I am thinking of applying some of these on a piece of cardboard and mounting it to the screen of my 50" RPTV via Velcro strips when listening to music. Which should I use over the TV, absorption or diffusion? The TV sits in between my main speakers.
Thanks
Greg
gsselling
Interesting. Hopefully, Rives will see this thread and offer some recommendations.
I have the same problem in my family room, i.e. a 55" rptv sitting between the speakers. For a cheap fix, I use two 2' x 4' panels of 3" pyramid foam, mounted to 1/2" pvc tubing. I guess you would consider this more of a diffuser than anything else.

It may not be ideal, but it was cheap, and it works. Solidified my center image, and allowed to the soundstage to deepen.
I think either would do the trick. But absorbtion is much easier and cheaper.
i don't see how you can possibly get the right answer without posting your room dimensions.

rhyno
I'm with Rd, "I've always heard absorb in front of you, diffuse behind you." Anything coming off the TV would probably be a bad sound, distortion. Best of luck Gsselling, acoustic treatment is always so site specific. Cheers!
You have a beautiful system. I love the look of those tylers. For a different take on the problem, I would suggest looking into getting a front projector for your room and have nothing in bewteen your mains. You mount a screen on the front wall and go from your 50" diagonal image to a 90" or 100" widescreen image instead. It is alot more fun and immersive with a big image and is also nice to retract the screen and it all goes away. It does not have to cost alot either and can be done quite well on less than $1500 bucks. It has worked quite nicely for me in my room.
peace
A quote from a smarter guy then me

"For someone with a very small budget, making the rear wall of a room totally dead may be the only solution. At least that gets rid of flutter echoes between the front and rear wall, though at the expense of sounding stuffy and unnatural. But it's better than the hollow boxy sound you get from a plain flat reflective surface. Another option is to make the rear wall of a room partially reflective and partially absorbent. You can do this by making the wall totally dead, and then covering it with thin vertical strips of wood to reflect some of the sound back into the room. If you vary the spacing from strip to strip a little, you'll reduce the coherence of the reflections a little which further improves the sound." - Ethan Winer

Either Absorption or Difussion should work. But I like Shiva's idea the best.
I vote on difusion. I'ts effective and easier to accomplish.
What do you want? A good spatial image, then your TV should not interfer in the sound field.
The problem with absortion is that it affects the character of the aural enviroment, changing the room frequency response. In most cases absortion turns the room acoustics dead, because it supresses echo (wich is good) and high frequencies (wich is bad). So, absortion is good to control room acoustics (primary), making it flat if desired. There are some physics and mathematical expressions that one must consider in order to make a good absorber at the desirred frequency range.
For me it looks like that you want the incident energy in the TV to be redirected so it wont affect the sound field prodiced by the speakers.
Scattering by arrays of elements is exploited in the design of broadband diffusors for auditoria and sound studios. Try build one to put in front of your TV.
Hope it helps.
Gsselling first thing I would do is to direct couple your TV to the surface it now rests on. I try to do this in most custom installs that I do.You need to do this as a base line before you try any other experiment . You have a giant resonator in your room that is out of control, no predictability as to what frequency it will store..how much and when.. it will be released only to mix with the mains. Direct coupling your tv will net two benefits. The picture will be better I have seen this benefit.The picture becomes sharper and color rendition is more accurate. Properly coupled to the support surface will allow the stored resonance generated by the projection set a place to dissapate to. Trying to isolate the tv from the room with rubber or foam will only make the problem worse..slowing down the release of stored energy. After the set is properly coupled then I would construct a panel framed with 1 by 2's lightly filled with long hair carded wool and covered with grill cloth. This panel could be made to be placed and then easily removed from in front of the tv. The wool is more linear and less likely to cause an AAAHHH sound or suckout of the midrange that man made fibers or foam do.Tom
Projection TV in between the speakers... I've had that for a couple years now... got tired of the constant gathering of sound in the areas beside it and above it... and oh, Gezzz, off of it's plexiglass cover screen. What to do? build it in. the space along each side of it serves no purpose. . . unless that's where you have your gear... and that's fine. Put shelves into the 'covering wall'. I designed and had built a 'false/covering wall' myself. the whole shooting match including trim run about $300 to $400 with the trim being a big part of the costs. Viola! Parralell surfaces, no place for sound to gather... but there's that big ol' glass making the sound harsher - Curtains. In a word, curtains. It was curtains for the harshness that was coming off the glass, that's for sure... though I did have to make sure about the material being used. Needs to be thick. or another lighter cover needs to be used to add to the compensation of the screen. that's the way i went. Still need to do something to allow the curtains to separate better, which simply means a better rod for them to hang off. If you want a pic let me know. Personally I have all my gear in the adjacent room... but did think about placing it in the 'covering' wall, but I prefer the appearance of it as is... nothing but speakers and furniture seems cleaner... and certainly quieter, and cooler. . . not to mention more secure if friends bring their kids along too. .. . but that's just me... and I do need to treat some more areas... but the wall helped immensely in imaging, sound stage, and esthetics... for less than the price of a, well, er, whatever costs $400. Way worth it. oh, and make sure you add access to the area behind the wall... pulling that big ol' TV in & out is definitely a bothersome chore... but not impossible.