Best screen material with acoustic transparency - Page 3

I tried different distances up to 1 foot, and I found that the distance only moved the peaks and nulls around, it didn't reduce them. I don't know enough about the physics behind comb filtering to discuss this though, only report what I found. Those measurements were with the screen roughly 12" from the source, but as I said, putting it closer or even farther had minimal effect on reducing or increasing the shear size of the peaks and nulls, and mostly just moved them around a little.

Acoustic phase is key in understanding whats going on here. I didn't post it because most people don't really understand it, but if there is interest, I can post those as well. You see drastic flip/flops added to the phase response which directly correlate to the response anomalies. As I understand it comb filtering is a function of the sound waves at different frequencies arriving at the "destination" at different times, attenuating and enhancing the frequencies in the "comb" shape. If moving the material farther away could reduce comb filtering, it needs to show up in the phase (our proxy indicator of time differences) and it didn't stop the effect, it just moved it around, which is exactly as I would expect. It really makes no sense to me that moving the mesh farther away would change that, but as I said, I just don't know enough about the subject to discuss it extensively.

Good stuff!

Some of the $1200 a piece speakers for theaters have plastic grilles with holes punched in them, go to any theater in the last decade and it a thick peice of vinyl with holes poked in it, Stewart actually recomended EQing their top selling audio screens that sold gazillions and comb filtered horribly if Im not mistaken.

There is some different methods for testing this stuff from my 3 years of looking into audio screens and Ive heard so much bruhaha about this and that being better and not better. Just buy whatever you think you will be happy with and you probably will, testing on anything but a full sized screen with your speakers in place, and your room treated is a crap shoot anyway. Buy what gives you a Bright, Vivid, Spectacular picture and EQ the sound if you dont like it. 90% wont know the difference in a Blindfold test, been there done that, and the 10% will probably pick the "screened " speaker as the non "screened" speaker like the audiophiles did in my tests.

We are building another theater in the guest house right now, I bought an SmX Proline 130" 2.23:1 screen and have been testing it out and if it combfilters, then I want all my speakers to combfilter because the sound is Phenominal!

Why you say Moire not an issue?, I just about done with my screen 4500 I used and Moire is driving me crazy. The brighter the image the worst it looks and 1080p material is even more notisable. I'll try to post picture later and more on my setup.

I have one of the most moire producing projectors there is for the guest house theater ( Epson 6100) and it Moired on everything but the SmX, the real SmX that is, not the SW 4500 everyone seems to confuse with SmX.

It may be the reason SmX didnt stick with the SW4500 if thats what they originally used. You have to rotate the heck out of the 4500, I barely have my SmX screen rotated at all, no moire

well what you are basically arguing is that the bad comb filtering is probably not audible, and I'm inclined to disagree. I would suspect the audibility of it is going to be very dependent on the material used to test with, the area that has the worse comb filtering (most is up high, but the audible range is more between 1 and 5k), and the spacing of the valley's and peaks. None the less, all that work to get the speakers response nice and smooth only to find peaks and valley's like that from the screen is disconcerting. I'm inclined to continue testing with larger pieces to see if it has an audible effect. Harman and Dr. Geddes have mentioned a simple ABX technique of recording the speaker playing back pieces of material with and without the change as an evaluation technique, I may try this.

my Moire isue with 4500, 135" 2:40:1 acreen. Epson 1080UB 16.5ft from screen, 14ft. 1st row seating. Front wall/ ceilling flat black, walls/ dark blue flat.
Here are some picture of whats happening:
1st. pic./ blu ray, zoomed to fit full screen/ all good,



2nd. pic./ zoomed to about 100-90" and you see what happens.



3/4th. pic./ zoomed to 16:9 blu-ray and you see as well (if I zoom out bigger, pic. is amazing).





The 4500 material turned very, very little. I purchased the 45 or something inches, not the 96 or something.
Is my projector too close? I could move that 1 more foot.

the reason dyslexic said moire is not an issue is because the Panasonic with it's smooth screen technology does not necessarily require you to tilt the material for 1080P. The Epson 1080UB does require for you to tilt the material so that moire would not become an issue for you. Did you get the Epson before or after you got your screen material? Did you buy it from SeymourAV? They are pretty knowledgeable over there and they would have likely told you that any other 1080P proj. was gonna require you to buy the wider material.

You could try to move your proj. back thus increasing the size of the pixels this may aid in the interaction that your seeing of the pixels and the weave. Good luck.

thanks, material was purchased from link provided in 4500 thread. I should have got the larger size. I'll try moving projector back 1 foot, if that doesn't work I can get larger material or Panasonic 3000. , I'll run this by my wife.

yourtoys7,

You mentioned you rotated the screen material very, very little. Did you try rotating it about 15 degrees. It sounds like you didn't experiment very much. You should have tried this first on a sample piece and then ordered enough screen material to make you screen. I would say rotate it more. If you can't I would just try it and if it works order more material.

i dont know much about this

I only rotated very little because I ordered shorter vertion of it, I might have to go for 96" or something. Then will be able to rotate more.

I wouldn't order any more material until you try rotating the material you have to see if that takes care of the moire.

my material is at the post office, I'll try and get it built this weekend and post snaps. I don't plan on tilting it, but will experiment before I attach the screen.

thanks, I have 1ft. x 1ft. and looks good, but not shure if thats enuph material to test. How big are the samples?

the sample they send should be good enough to test. Make sure you are sitting at a relatively close enough distance to see the effect. Try moving your head around and changing your seating position (walk up a bit close, sit on the floor, whatever). If at any point you see the effect in this testing, it's likely to show up with the larger material.

Finished the screen - no moire for me; and I also tilted as much as I could but I could only get maybe 5 degrees. Its so awesome.

Dyslexic

What projector you running, distance from screen to lens (I'm 16.5), screen size (135" daig.).

I'm running the Panasonic AE3000 - my lens is just over 14 feet to the screen.

The screen is 48.5 High and 115 Wide - that's about 125 diagonal......the panasonic has smoothscreen technology so moire is not an issue....

I"m a little surprised people aren't more concerned with the sound quality aspect of the screen. If there are any questions, please do let me know.

I didn't want to make a lot of comments about what this effect really was, I suspected that, while related to comb filtering, given it's classical defenition and common use, it was actually more similar to diffraction (which is part of what can cause comb filtering). After discussion with an acoustic physicist and a few friends a bit more knowledgeable than I, it was describe as being very similar to edge diffraction or horn mouth diffraction. In other words it has as detrimental an effect on sound as a really bad bit of edge diffraction.

I also made up wave files of music and movie portions, with and without the screen, and attempted to ABX. I was succesful 100% of the time, as were others I had try it, but it's not a good test. It's a linear distortion (with some non-linear effects as well) caused by a physical barrier, therefor the "aurilzation" like technique I used assumed the two recordings were done identically. I tried adding it synthetically, but lack the knowledge or ability to truely match what the screen was doing. Since it's not really comb filtering, you can't just add a comb filter. I also had a hard time picking apart the nature of the non-linear distortion it was adding, so I could only guess what type to add. While for some this may not be important, for me, it's a pretty big issue. I spent a lot of time and money minimizing the types of distortions which are found to be most audible, and so to re-introduce them with the screen seems like a pretty big waste.

I'd really like to see manufacturers and companies begin supplying impulse responses with the response graphs. This turned out to be the recommended way to properly interpret what was really happening here, and it really became clear from those that the effect was not small, and likely to be audible (which I believe it is).

I'm reluctant to say there is something out there that fits my needs, at any price. The 4K kept emerging as more and more of that ideal solution, but I'm very concerned about the picture. No idea if the picture is any worse, but the small sample made it hard to compare, but seemed less "brilliant."

The sound to me is very good, but its not same as theyre in front of you. You sure sacrificing some sound, but the gain of the size image you you get is far grater to me.
My next step (when ever that will happen) is to have electric screen. When I want to listen to music, screen is up. Foe movies I'll just drop the screen and enjoy the show.

it depends on the distance of the viewer from the screen that makes it clear. the resolution should be maximized from a distance. it matters a lot.

It has been a while since anyone posted anything about this fabric. Is there anything else going on out there?

I'm curious about the Seymour XD material. I've had a Dazian CCC screen for over 2 years now and have been generally happy with the sound transparency, but would like to try something different in an attempt to brighten and sharpen up the picture some. Seymour XD looks like it might be the right stuff. Can anyone who has tried this material provide any feedback? I have the Panasonic AX-100 PJ, so I don't think moire would be much of an issue.

Go to the screen forum and then to the Seymour Screen thread to read comments from users about the XD material. Call or e-mail Chris and get a 8.5 x 11 sample or pay $20 and get a much larger piece of the material to try out.

Hi All,

I'm still in the early of my dedicated HT build but have been looking into AT screen options this past couple of weeks. I'm looking to go the DIY route and therefore just read the prerequisite original SMX material thread from the archives (SMX begins..).

Obviously this was back in 2006 but from what I have found there has been nothing on a similar scale since. In this thread there is a suggestion that the original SMX fabric was SW 4500, but if you read the archived thread it it almost certain it was a special order of SW2390 in the P06 (Chaulk) color (although in one post Ruben claims it is a custom weave somewhere between SW2000 and SW2390). The spec's for the 2390 can be found here.

So.... if this really is the magical AT material and nothing better has been found since, then all that is keeping the keen DIYers from it it enough purchasing power to warrant a special production run and someone to coordinate the effort. I think the magic number of people would be around 100. What are people's thoughts? Are there close to 100 people out there that would be interested in rallying behind a group buy?

Just thinking out loud at this point...

Last year, I bought screen material from Seymour AV to build a 100" screen. I have yet to roll out the material as I'm still building my theater, however, I did compare my Seymour AV material to w00lly's SMX material and I couldn't really spot a difference....



With that said, I just sent Chris an e-mail as I am interested in their new material