Film-Tech Forum ARCHIVE: Placing screen speakers with bass cabine on botton and HF on top behind screen

This is topic Placing screen speakers with bass cabine on botton and HF on top behind screen in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Marin Zorica (Member # 1716) on 12-07-2009, 09:36 AM:

I having one cinema, a really bad room situation, 32meter long, 11 meter width....so 3:1 which is really bad in aspect of cinema acustic, more prefered for live music and so, also secound thing is that first row of seats is about 10m from screen because there is 1m height stage. In fact that wouldn't be any kind of problem as I need to worry as nobody will invest in rebuilding of house, now we wanted to upgrade sound, found some KCS S-2500, it has 47cm deep cabinet for low freq, and mounted on top HF driver....the thing is that I can put it behind a screen because i have only 42cm space between back wall and screen. But, i do have some space below the screen, there is some black curtain which is in parralel with screen and from it to back wall there is enought space to put speakers, so I was think....that is too low for speakers, and also that curtain has higher amount attenution of high frequencies, so maybe to put LF cabinet down, and HF driver to get it mount upp in 2/3 from top of screen as usual?

Don't know if anybody did do anything like it? I did hear for some system that HF drivers are mounted on top of screen and so, but newer had a chance to hear how that is working.

Posted by Louis Bornwasser (Member # 3063) on 12-07-2009, 12:13 PM:

If the acoustics are bad (live) enough, you will be better to put the LF low and mount the HF above the screen, with the idea of aiming toward the floor, thus avoiding any reflections from the rear wall.

Yes, this is bad form, but better than the alternatives. Louis

Posted by Cameron Glendinning (Member # 3516) on 12-07-2009, 03:00 PM:

Better still, get a different smaller horn! For the best results in a room like yours use a 60 x 40 style like web page
It is also possible to build a box that would fit within your backstage.

One more thing I would suggest is a backstage acoustic treatment.

Louis is on the money as usual regarding how important correct installation of the horn is. To me it is more important than brand, ie a great speaker will sound just as crap as a no name one if they are both installed badly!

Posted by Marin Zorica (Member # 1716) on 12-07-2009, 06:26 PM:

Well....I was think same as you two did, also was again to check room, is not bad at all it seems on first, well reverbation time is quite small is you count size of it, so less than 1 second or so, on stage there is a some flatter echo, because of ceiling, and normally back wall would be treated with apsorber or something I will need to get "In" financial situation.

On other hand, is not possible to put HF horn above screen, because screen frame top is about 10cm from ceiling and in that space curtain console is mounted. So probably horn will get on 2/3 of from top of screen as usual. To bad this isn't to be BI amplification, because than I could compensate, because when HF is mounted on top, there will be bit more away than LF unit which is on bottom from seats.

Posted by Gordon McLeod (Member # 33) on 12-08-2009, 10:43 AM:

AMC did that for years with some of their Torus suck screens

Posted by Richard Hamilton (Member # 321) on 12-08-2009, 12:50 PM:

about 15 years ago, I walked into a room with a "suck" screen. It looked and sounded horrible. I told the local tech that I wasn't going to fuck with it. I cleaned the optics and set dolby levels and walked away. LJ fucked up with this idea. He must have been in bed with the vampire

Posted by Cameron Glendinning (Member # 3516) on 12-08-2009, 03:06 PM:

quote: Marin Zorica
and normally back wall would be treated with apsorber

Just making it clear that I am recommending back stage behind the screen not the back wall. Its the early reflections that cause the biggest intelligibility issues.

The right horn correctly installed could have very few issues with the back wall reflections.

There are speakers that can fit within 40 cm stage depth perhaps its better to wait or save for some?

What is currently backstage? perhaps its better to refurbish?

Posted by Frank Angel (Member # 248) on 12-08-2009, 08:02 PM:

If you must place the bins below the screen, there is a very light weight material that you can use which is fairly transparant acoustically and it is has excellent light absorbing characteristics well -- any image spill on this stuff literally becomes almost invisible. It is black satin. We found it much better in that respect even than the traditional velour for the masking surround, it's much easier to work with because of its light weight and as I said, sound will pass right thru it practically unscathed, especially low end stuff. You can get Black Satin at Rose Brand in NY/NJ.

Posted by Frank Angel (Member # 248) on 12-09-2009, 09:09 AM:

Sorry, I misspoke....it's black VELVET, not satin.