Are screens acoustically transparent?

Discussion in 'Displays' started by Jonty Rees, Apr 14, 2004.

  1. Jonty Rees

    Jonty Rees Stunt Coordinator

    Joined:
    Nov 13, 2003
    Messages:
    81
    Likes Received:
    0
    Trophy Points:
    0
    Just in the Scratch'n'sniff stage of looking at a projector setup, so I'm wondering if I would have to rearrange my speakers to avoid them being muffled by a pull-down screen.

    I'm thinking of having the screen pull down in front of my current setup, consisting of a 35" Sony TV set, large Infinity speakers on either side of it and a center channel on top, with all my components on a rack below. It's all tucked into a built-in entertainment center, set into the wall. We watch a lot of TV in the room, and I don't want to give up the TV performance of the direct view set, nor do I have much space for a new 16-9 RPTV, (I just don't like the regular TV pic on any of the newer sets I've seen, Plasma, whatever). On the other hand, we watch quite a lot of movies, and a letter-boxed 2.35:1 movie on a 35" TV is REALLY small.

    It's a strange shaped room also - about 22x15, high ceiling, with the TV in the middle of one of the long walls, sofa about 10 feet from it. We had an extension built on behind the sofa, so there is kind of an archway leading out to an office with a vaulted ceiling with a skylight in it. So light is kinda difficult to control during the day, (no biggie, we would watch movies at night mostly).

    My thought is that this would cover both our watching preferences, and I should be able to switch between TV and Projector through my receiver, right? (Onkyo Tx-DS575).

    Thoughts?
     
  2. ChrisWiggles

    ChrisWiggles Producer

    Joined:
    Aug 19, 2002
    Messages:
    4,791
    Likes Received:
    1
    Trophy Points:
    0
    some screens are acoustically transparent, and they can vary in terms of how acoustically transparent they are. I'm not super familiar with pull-down screens though, I would assume you could get acoustically transparent pull-down screens, but not sure.
     
  3. Matthew Todd

    Matthew Todd Second Unit

    Joined:
    Jan 3, 2000
    Messages:
    338
    Likes Received:
    0
    Trophy Points:
    0
    The acoustically transparent screens are either microperforated (lots of very small pin holes through the screen) or they are woven. They are quite expensive too.

    The microperf screens can have moire pattern problems with digital projectors depending on the native resolution of the projector and the size of the screen. Woven screens do not exhibit this problem.

    That's about what I can add right now, as I'm not overly familiar with them either.
     
  4. SethH

    SethH Cinematographer

    Joined:
    Dec 17, 2003
    Messages:
    2,867
    Likes Received:
    0
    Trophy Points:
    0
    If you've got the cash to spend there are some THX certified screens which are certified based on their transparency.
     
  5. Scott Dautel

    Scott Dautel Second Unit

    Joined:
    Oct 6, 1998
    Messages:
    471
    Likes Received:
    0
    Trophy Points:
    0
    Hi Jonty ...

    I have to congratulate you for having excellent forethought. You've hit on a real problem for many of us who have jumped into front Projection.

    There's no easy solution. Typical pulldown screens are NOT acoustically transparent. They will muffle your center channel somewhat. I'm talking about pulldowns that are reasonably priced ... you can get a std Dalite Model B manual pulldown for ~$200. Acoustically transparent screens seem to jump the price up to nearlt $1000 or more. It seems the problem is associated with tensioning. Low cost pull down screens are not tensioned, they just hang. The microperf screens apparently have a tendency to wrinkle when they hang without side tensioning. Also, I think they may wrinkle when they retract/roll up.

    Of course, you can special order a tab-tensioned, electric motor driven, ceiling drop, acoustically transparent screen from Stewart, Dalite, etc ... but who really wants to pay more for their screen than they did for their Projector.

    One other solution is to special order about 8 feet of Microperf screen material, then make your own screen over a wooden frame. You can then hang it from the ceiling and take it down when you want to use the std. CRT television behind. This is what I do (thought not AT yet), but it's a big hassle storing the massive fixed screen.

    You can also use a std (non-acoustically transparent) pull down screen and turn up the CC volume when the screen is down. It's not a bad solution ... I would estimate that the screen may muffle the CC volume by ~20% but I never measured it. Anecdotally, I would say that there is also a little loss in dialog clarity.

    The really best solution is to find a way to mount your CC speaker below the screen and TV. I'm considering building a little narrow custom table just below the screen and putting a long wire on the CC speaker, which allows me to physically move it when in "FP HT mode".

    Comments about light control ... this is likely to be your greatest frustration. In the summer, when sunset is well after 8:00 PM, you will hate it. For FP to look really good, you need a VERY DARK (95%) room. In your case, I think a very high gain screen is justified. See my comments about FP & screen gain in this thread

    Scott
     
  6. Jonty Rees

    Jonty Rees Stunt Coordinator

    Joined:
    Nov 13, 2003
    Messages:
    81
    Likes Received:
    0
    Trophy Points:
    0
    Thanks for the input - I'm sure this is going to take me a while to work through, (and pay for! I'm really cheap which complicates matters further - no $1000+ screen if I can help it). It's always hard to have your cake AND eat it.

    I thought about having a long wire on my center channel, but then it drops the dialogue down to floor level as if people are talking through their feet. I'd still have the problem of my main front speakers being behind the screen, as mine are close in to the side of the TV - not ideal, I know, but a concession to spousal interior design. I think if I do take the projector route, I'll just crank up the volume from behind the screen.[​IMG]

    The light thing may be more of a problem. Maybe a curtain across the archway would work. The drawback with a high-gain screen is that blacks are not very black, correct?
     
  7. Matthew Todd

    Matthew Todd Second Unit

    Joined:
    Jan 3, 2000
    Messages:
    338
    Likes Received:
    0
    Trophy Points:
    0
    Another thing to consider is that you can order pull down screens with a custom amount of "drop" before the screen surface begins. It is possible to have the drop only perforated, although I'm not familiar with how much this costs (seems like it may be less) or if it affects the screen surface below.

    Matt
     
  8. Jonty Rees

    Jonty Rees Stunt Coordinator

    Joined:
    Nov 13, 2003
    Messages:
    81
    Likes Received:
    0
    Trophy Points:
    0
    Maybe I could use a little needle and poke holes in the top part of the screen!

    Actually, the more I think about it, light control and viewing angle might be my bigger problem. I need to take some proper measurements.
     

Share This Page