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HA Progress 3.0
im more concerned about eating up reflections. i got a couple of samples of black paint from lowes, but i dont think either will be what i want.

for now, the next step is to get the trim measured, cut, primed and painted. i will do that while my wife paints the walls, let it dry and hopefully be able to tack it up tomorrow evening.
do the needful ...
Hue | Sonos | Harmony | Elk M1G // Netatmo / Brultech
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It doesn't need to be velvet necessarily. Something dark with a slightly rough weave and no reflective type thread content will do a good job. If it's on the wall behind the screen, it shouldn't be getting any real direct light, right? A little leakage around the edges maybe, but the lens should be keeping the light on the screen itself. It mostly should only have to deal with doubly reflected light, what bounces off the screen out to the rest of the room and then back again.

Thousands of years ago, when I had a home theater, I had sort of dark wine red curtains behind the screen, and that worked fine. I had the same curtains on the back wall, so there wasn't too much doubly reflected light either.

And don't forget sound treatment as well, it's equally as important.
Dean Roddey
Software Geek Extraordinaire
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jkmonroe Wrote:im more concerned about eating up reflections. i got a couple of samples of black paint from lowes, but i dont think either will be what i want.

for now, the next step is to get the trim measured, cut, primed and painted. i will do that while my wife paints the walls, let it dry and hopefully be able to tack it up tomorrow evening.

I got specialty paint, very thick, only available in quarts (and wicked expensive but cheaper than fabric). No reflection at all. But thinking about it more, i'm not sure I'd want to paint a wall as it'll take 2 solid coats of primer and 2 coats of new paint over it to cover it. With latex paint thats some serious additional thickness.
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Dean Roddey Wrote:... And don't forget sound treatment as well, it's equally as important.

good call. been doing some reading on acoustic panels and it looks like i might be able to make my ceiling panels 'acoustic'. lots of good information over on AVS.
do the needful ...
Hue | Sonos | Harmony | Elk M1G // Netatmo / Brultech
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I have beau coup school of hard knocks experience in this area, so ask here as well and I'll kick in.
Dean Roddey
Software Geek Extraordinaire
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jkmonroe Wrote:good call. been doing some reading on acoustic panels and it looks like i might be able to make my ceiling panels 'acoustic'. lots of good information over on AVS.

...oh and then there is the "Starry Night with shooting stars" system that needs to be installed above the ceiling treatment.

The worries are endless!
Thanks,
Dave Bruner
Cool
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Keep in mind on the ceiling that it's really the first reflection point that's the issue there, because your speakers and you are a distance apart. So there's no direct reflection to the ceiling and back down.

When you a music studio, where they are often using near field speakers on the desk just in front of them, then you get direct up and back down reflections and you need to deal with that. In a theater scenario, if the speakers are some distance away from you, then the angle there gets wider and the reflection point between you and the speakers is where you want to treat. Putting something directly over you may not get you nearly as much benefit in that case.

The corners are usually the worst, depending on room shape, so doing the corners will get you the biggest bang for the buck. They channel energy coming from multiple directions back at you. Then do the area of the wall directly behind you probably as the next best bang for the buck.

If you really want to get into it, get an analog SPL meter. The defacto used to be a Radio Shack model, but they don't exist now. I'm not sure what has replaced it. But find a decent analog SPL meter. Then find a bass frequency sweep wav file, that does like 300 down to 40 or below. Play that at reasonable volume and put the SPL meter at the listening position (and move it around since a small position change can make a big difference.) Don't worry about anything outside the listening area.

You'll see the frequencies at which it peaks and dips. That'll tell you where to attack first. Those frequencies are directly related to the length of one or more of the axes of the room relative to the sound wav length at that frequency. With the SPL meter you figure out your worst problem areas and attack those. Initially, if you have the raw materials for the bass traps, you can move them around manually and do tests of different thicknesses in different places before you commit to putting them in place.

There are various calculators out there to work that out. But basically it's 1130 ft/sec for the speed of sound. A 40hz sound wave is 28 feet long. So if one of your axes is 28 feet, you'll have an issue in the center of that axis at 40hz, and so on. If one of them is 14 feet, you'll have one at 40hz and one at 80hz (half the wave length so they both equally fit that length.) Those center nodes are the worst. You'll also have some issues at some odd ratios along the length. There are also good charts out there that show those. The simplest and most effective thing of all is to make sure your viewing position front to back is in between any of those prominent problem points.

Another one of the biggest things you can do, which maybe you could still do, is to make the area non-rectilinear. Even getting one wall non-parallel will help a lot. That means that reflections don't go straight back in the direction they came from.

If you really wanted to get ambitious you could make a nice sized diffuser for the back wall. There are plenty of plans for those out there. They create a randomized surface that breaks up sound waves across a wide range of frequencies.
Dean Roddey
Software Geek Extraordinaire
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Dean Roddey Wrote:If you really wanted to get ambitious you could make a nice sized diffuser for the back wall. There are plenty of plans for those out there. They create a randomized surface that breaks up sound waves across a wide range of frequencies.

yeah, ive thought about it. the room is like an echo chamber right now, but it's a concrete floor with no furniture. acoustic panels behind the speakers and on the ceiling, plus diffuser on the rear wall might be just what I need to do.

besides, i like the look of diffusers. adds some 3D interest to the room. Smile
do the needful ...
Hue | Sonos | Harmony | Elk M1G // Netatmo / Brultech
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jkmonroe Wrote:hmmm ... so you have a 2.35 screen now? which means you would be doing CIH to switch. would you need a panamorph for that?

im not going to futz with it now and just go 16:9, but ive been giving some thought to how to best migrate to 2.35 in the future.

Yes, I CIH my projection. The one catch is when I get a 2.4:1 movie and I have to bleed onto the side frame a little. But Falcon's velvet is super dark and it's almost impossible to see the bleed. I swear I spent 3 hours with my spreadsheets making sure I had all the right measurements for a dolby standard setup, and then I missed on the projector mount. Not because I calculated wrong, but because I did so for 2.35 instead of 2.4. Crap. My 2.35 has about a 1/2 inch of bleed just for safety margin. 2.4 doesn't quite fill the vertical; it's off by about an inch or so. I'd need to move my projector back about 6 inches to get a full height 2.4:1. I may do it at some point once I get the control system working.

My goal is to have CQC drive movie selection from a repository so it can send zoom/pan instructions to my JVC. Struggling with the setup at the moment and hoping for that DLNA driver we've been talking about.
Flamin' Noobie...
Warp speed now and don't give me any of that dilythium crystal crap!
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rtarver Wrote:My goal is to have CQC drive movie selection from a repository so it can send zoom/pan instructions to my JVC. Struggling with the setup at the moment and hoping for that DLNA driver we've been talking about.

What are you struggling with? I don't think that the DLNA driver will really make any difference in that particular aspect of it. It's just another way to get to the same data.
Dean Roddey
Software Geek Extraordinaire
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