[Photon46]

One "rule" repeated over and over on audio forums pertains to the acoustic evils of wall mounted televisions. The skeptic in me wonders if the reality is equal to the belief. On forums one often sees systems that have speakers positioned four to six feet out in the room and a flat screen mounted a few inches off the wall. The plane of the television is very near to the plane of the wall. Both the glass/plastic surface of the television and the surface of the wall are smooth and hard so how much difference is there? Has anyone done acoustic analysis of the actual difference between a bare wall and a flat screen on the wall? One always hears how much better it sounds covering the tele's screen with a blanket, quilt, or acoustic panel but that only proves that the room sounds better with acoustic controls in that spot, not that the television was the problem. It's easy to understand how a reflective panel parallel to the speaker plane could adversely affect soundstaging, etc., but when then tv is so far behind the speakers?

[BobRex]

I'm following the same logic.  Additionally, my tv is above the plane of the speakers, so I would think (guess??) that the effects are even less.  Can't wait to read some of the responses.

[thunderbrick]

Has anyone addressed the question of whether the audio system sounds better when the TV is on vs. off?

[JRace]

http://realtraps.com/art_front-wall.htm

Since writing this article, several of my friends who are industry professionals suggested I at least try adding absorption in front of my large glass TV as a test, to see if I hear an improvement in imaging. Even though the ETF software shows no significant reflections, I tried it anyway. A friend and I took turns, with one of us listening while the other first held and then removed absorbing panels in front of the TV. The room is shown in the photo at left. The only change either of us noticed was a very sight lowering of the overall room ambience. This makes sense given that the room was already free of all major reflections.

One situation where absorption on the front wall might be useful is when the surround speakers face that wall. In my case the surrounds face each other and fire across the width of the room. But if they were facing toward the front of the room, and the total round trip from surround speaker to TV to the listener was 20 feet or less, absorption in the front of the room could help in that case.

[Austin08]

Even thought my speaker are 6fts way from the wall behind I can clearly hear the different with/without my DIY 4" 24x48 panel infront of my 65" tv. I guess because my speaker has open back design (SS8) ?

[JRace]

Yes, open back, dipole, bipole, omni...will have a significant amount of energy radiating backwards.

[WGH]

Covering the TV with a light weight colorful Mexican blanket definitely improves the sound and I then don't have a giant 60" eye looking at me either. I still like the wall mount TV, as far as I'm concerned it is the only way to go.

[murphy11]

I took hundreds of measurements in my basement with REW and had an equipment stand and wall mount plasma 30" behind my ONIX Strata mins. I was not really using the plasma anymore and took it off the wall. My measurements did improve. I took the equipment stand out as well and measurements improved again. They were not huge changes on a graph, but I wanted the best sound I could get and moved the TV upstairs and I'm very happy I did.

I wish I kept my before and after measurements but unfortunately I did not. Literally a few hundred plots and they got overwritten.

For most people who have TVs mounted, they won't want to take the TV down so some kind of throw blanket or acoustic panel covering the TV will probably be the best option.

[jimtranr]

I'd say the short answer is "yes."

As the first photo indicates, my current setup does not present a wholly comparable situation given the asymmetric foward-of-the-wall-plane location of the 40" flat screen, but forget the flat screen for a moment. Prior to treatment of the wall section immediately behind the flat screen with the GIK 244 shown, that space was partially occupied by a plexi-fronted, framed Cezanne print measuring 25"W x 22"H. Comparing sonic output with the print in place and that same section bared (it's wood-siding wall) resulted in better left-to-right channel balance and a more spacious and dimensional right-side presentation with the print removed, i.e, on bare wall. (It's even better--considerably--with the 244 in place.)



Or let's take the second photo's situation of a large flat surface positioned nearer wall center, in this case a ceramic-tile-and-glassed-firescreen chamber of reflective horrors. Although well behind the plane of the forward-radiating speakers (though bass port output emerges from enclosure rear) and at some lateral distance from them, that large surface "flattened" the fore-to-aft soundstage, smeared individual imaging, and buried low-level detail, all of which was considerably improved by the placement of the horizontal 244 shown in Photo 1.



(Note: My preference would be to replace the Kitchell print above the fireplace with acoustic treatment. But this is a shared, very lived-in living space in which I wish to maintain at least a modicum of domestic peace. I may, however, look into a custom-sized "234" to cover the flat screen during serious listening sessions.)

[Photon46]

Thanks guys, Murphy11 in particular. To restate, my doubts have nothing to do with the fact that our audio systems usually sound better with some sort of acoustic treatment on the back wall. I have a pair of Gik traps on the wall behind my speakers and cover my tv with a thick quilt when listening. My only question is whether a wall mount tele is substantially worse than a bare painted wall, paneling, patio door etc.

[Austin08]

IMO, glass do more harm than bare drywall or paneling due to being more solid nature.

[Photon46]

IMO, glass do more harm than bare drywall or paneling due to being more solid nature.

If an acoustic wave strikes a boundary, it is either partially absorbed or reflected at that junction depending on the resonant frequency and density of the material it encounters. From my understanding of acoustics, I don't think that high frequency acoustic waves exhibit very different behaviors when striking a plaster wall vs. a glass wall. Is there enough energy in a high frequency acoustic wave to cause absorbtion into a painted plaster surface? Lower frequencies will have enough energy to exhibit different behaviors encountering glass vs. plaster but those aren't the part of the audio spectrum that influence our perception of things like "glare" and "ringing."

[sharpsuxx]

Even more than the acoustic affects are the psycho-acoustic effects.  Having any large central object between your speakers sucks the sound stage towards it and sucks the space out of the recording.  Unless of course you are listening with your eyes closed all the time.  It is a hard effect to avoid but even with a sculpture with no flat facets and lots of air throughout it, it will still seem to squash the sound stage.  This is all separate from the reflections which are another issue, if you really want to have a devoted 2 channel listening room, leave the TV out of there.  If you must have one, cover it with something that is non reflective and blends with the walls.

[macrojack]

My 59 inch plasma is hanging on the wall between my horns. Either the directionality of the horns makes this a non-issue or I just don't care enough to seek this problem. Either way, I'm good.

[Glenn Kuras]

If an acoustic wave strikes a boundary, it is either partially absorbed or reflected at that junction depending on the resonant frequency and density of the material it encounters. From my understanding of acoustics, I don't think that high frequency acoustic waves exhibit very different behaviors when striking a plaster wall vs. a glass wall. Is there enough energy in a high frequency acoustic wave to cause absorbtion into a painted plaster surface? Lower frequencies will have enough energy to exhibit different behaviors encountering glass vs. plaster but those aren't the part of the audio spectrum that influence our perception of things like "glare" and "ringing."

Right... I kind of laugh every time I walk into a room at RMAF and they have covered the mirror and not the other walls.  Both are going to reflect pretty much the same.

[Austin08]

Right... I kind of laugh every time I walk into a room at RMAF and they have covered the mirror and not the other walls.  Both are going to reflect pretty much the same.

Glenn,

Thanks for clarify that. I always though glass will do more harm than bare wall.

[Glenn Kuras]

In same ways it can help  as it lets low frequency out, which is always a good thing. The problem can sometimes happen  that you might have a window behind a speaker and not the other which might through things off a bit. Not the end of the world but can happen. 

[martyo]

My 59 inch plasma is hanging on the wall between my horns. Either the directionality of the horns makes this a non-issue or I just don't care enough to seek this problem. Either way, I'm good.

"I just don't care enough to seek this problem".

  A most refreshing answer.