Two feet behind the front may be OK -- let your ears be the judge of whether another foot or two would improve things. For when you do some serious listening, you could try throwing an acoustic blanket over the TV -- it's a lot easier than moving it and may give you OK results. |
Switching to front projection was the second best thing I've done for my two channel sound.
A blanket on top of the TV would kill high-frequency reflections, which aren't a real problem because the speaker is more directional at those frequencies. It won't do anything for lower frequencies which are hitting it. |
OK. Let's see. A 32" TV you say? (diagonal?) And let's say the front face is represented by a 32" dia. disk. 32" is 2.6 feet. If you let that dimension be the length of the half wave it will reflect, then the full wave dimension is 5.2 feet. If you divide the speed of sound (approx. 1100 ft./sec.) by 5.2, that would be a frequency of 211 Hz.
The TV will be essentially invisible to any sound below that frequency, since it won't reflect them, and as for sounds above 211 Hz, unless you're using a dipole/planar type speaker, there probably will be minimum reflection, since most frequencies above 211 Hz (and certainly above 500 Hz) will be projected forward. |
Hey all, good input. I never thought of using the blanket. I do most of my "critical" listening at night with the light off so cosmetics not an issue. Try it you will like it.
A projection TV with a drop down screen is definitely on the wish list for the future. |
I like the idea of the blanket as well. My wife makes designer quilts and I have one the size of my 60" RPTV, which is recessed into the wall leaving 16" projecting out into the room. My speakers are about 18" in front of the plane of the TV and 22" to the sides. Your distance will be different depending on your speakers' radiation pattern, height, timbre, etc. It is a reflective surface and scattered high frequencies. The sound is alot truer and natural with the blanket in place. Good luck |
I'm not disagreeing with anyone, but I'm confused about how a tv would have a negative effect on low frequencies since it seems to ubiquitous. I would think the high freq. would cause the problems?? |
hey ...guess who
I did a field trip once....using a percussion instrument,a small wood block ,the ones they use for latin music etc...You could use a triangle or any inexpensive bongo.
Go outdoors and strike it several times.Get used to the sound "au naturel".Make sure there are no walls or your not in between houses because you will get the awful cement bounce.So drive out far from walls.What you are hearing is the full harmonics and full dynamics.
Now take that same instrument,go to your bedroom and try it a foot away from your bed....oh where are those harmonics and dynamics...all sucked up.=absorption
Now go and strike it a few inches from your RPTV,mine was a pioneer elite,piano black etc...What do you think happened????
I'll leave you hanging and see if anybody wants to take a guess?I'll post again tomorrow.... |
Robm, I didn't see anything suggesting that low frequencies are a problem. Nsgarch calculated that only higher frequencies than about 200 Hz would be affected. The issue, I believe, is potentially one of soundstage and a bit of higher end distortion if the same music is hitting your ears at different times. Of course, that always happens but it's best when controlled through good room design and speaker placement. It's one of the reasons first reflection points are often damped or diffused. |
It is not an issue of low frequencies. It is only an issue of high mid and high frequencies. They have shorter wavelengths and bounce around, affecting the sound image that reaches our brains. Absorption of high frequency reflections is a good thing, to a point. Nobody likes an anechoic room, but too much reflection is a bad thing. |
part 2
Ok ....everybody including me thought it would be reflective.After hitting my instrument ,it turned out to be ...absorbing the sound ,just lke a matress or bed would.It is therefore a huge issue with low frequencies ,because it acts like a bass trap + overall absorber...hope it helps....It is after all a big hollow box!! |
Sorry, I did read the post backwards. It makes sense now. I'm with everyone else. A blanket works good (thick) for listening sessions. Although, I tend to accept the lack of soundstage in order to watch tv while listening sometimes. |
In my old room (a dedicated LEDE room) I had some Infinity Prelude MTS set up and sounding amazing. The depth is something I'm still trying to acheive in my new room. Anyway, we decided to add a 36" Sony WEGA HDTV monitor to turn it into a theater. The monitor was placed between the speakers and the imaging went to hell. I tried experiments with draping a big heavy blanket over the monitor to try to get the imaging back and was only marginally successful. Then I had an idea to create a "stealth shroud" around the monitor. I took a pair of window screens that were close the the side dimensions of the monitor and glued Sonex foam to them. Then attached them to each other using some 3/8" dowels across the top of the monitor (turning it into a sort of cage around the monitor). I put a few Sonex panels on top of the dowels but left enough space on top and at the bottom of the screens so that air could still flow. This improved the imaging immensely. It wasn't quite like the monitor wasn't there but it was close. |
After I painted my old apartment, the first thing I set up was the stereo. Moved in the couch, rug, set up the speakers and let it warm up. The imaging was beyond belief. Not only did images actually jump out at you, but they materialized ubove & below the speakers. Living conditions dictates that you cannot have a seperate room for a stereo, and another for video, but this would be ideal conditions. |
Everybody has this problem in a normal livivg situation. The only recorse is to move the speakers as far out as possible. Now I don't mean the speakers should be in front of your face, this will depend on the size of the room. People say drape a blanket in front of your TV, but then your friends start to look at you funny. just learn to live with it unless you can afford a dwelling with a seperate TV room. |
Interesting stuff about "stealth" cover for TV.Sounds like Defense Dept .stuff.I had same phenomena when friend had is dog cage between speakers with blanket over it.I told him just use blanket when they go in for night and your stereo is of.Made big difference.But even though the cage had huge gaps and was not a solid it made difference when removed.Too many folks keep their rack between their speakers when they could sue long speaker cables or better XLR connects between pre and amps on floor.I have thought of "treating" my traditional 10" by 60+" windows behind my Speakers with either sonnex tiles on plywood and just hinge them to swing into a full square when listening better to use a diffuser as opposed to absorptive pattern to do so.think I migh also try buying 6" plastic pipe using acoustic tile or at least on half of it.Then finish by making pedestals that then and this way you can realy tune the room at least somewhat concerning the speaker refelction.Can be big benefits for little money.But even cheaper is getting clutter around speaker cleaned as much as room permits/.
Cheers
chazz |
