Where do movie theaters put their subs?

Discussion in 'Archived Threads 2001-2004' started by Earl J, Mar 20, 2002.

  1. Earl J

    Earl J Stunt Coordinator

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    I was at the local AMC Theater over the weekend watching Ice Age (fun movie by the way), and started wondering where the heck they put their subwoofers and how many they typically use. It was a really large theater and we were seated dead center. Do they put them under floor? Behind the screen? Also does anybody know what brand of subwoofer theaters tend to use?
    Just curious[​IMG]
     
  2. Phil Iturralde

    Phil Iturralde Screenwriter

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    The majority of the Theater placed their sub's behind the screen. IMAX demo reveals their 7' foot high dual-sub behind the screen, left from the center.
    Quantity depends on which Theater Speaker package they purchased. Check out the JBL PRO Website.
    Phil
     
  3. jeff lam

    jeff lam Screenwriter

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    I got to play bass for a church service once that was held in an AMC theater at Onterio Mills. I was right up against the screen on stage. The subs are all the way across the front floor just behind the curtain. There must have been about 10-15 18" subs in their cabinets spread across the front of the theater. They are just under the screen. They were just normal Pro Audio subwoofers(didn't have a brand name on them). Now this was a fairly large theater(3 section/stadium seating), front stage was about 30 feet deep from screen to front row. This was no IMAX or THX certified theater but was larger than most stadium theaters.

    So, nothing special behind those curtains, just PA subs(a lot of them).
     
  4. Juan Castillo

    Juan Castillo Second Unit

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    Speaking of theaters... I saw Brotherhood of the Wolf this past Saturday in a Stadium type theater in Austin. I hate that I have to travel over an hour to see some movies because local theaters in College Station keep movies like Monsters Inc in rotation for 10 months. Anyway, thats a whole different topic. I really liked this movie, despite the use of cgi/martial arts in a period film. I thought the best part of the movie in this particular theater was the soundtrack. It was really loud, and really added to it. Anyway, I noticed that before the movie played, during the commercial filler time, the sound was coming from behind the screen. It was very directional. While during the movie, it was obviously coming from the speakers on the side walls of the theater. So, do any of you all know how Big theaters are set up? Do they use different hardware for stereo audio? If I counted correctly, there were 8 or more speakers on the side, and a couple behind the seating area.. This is obviously not 5.1, nor 6.1, nor 7.1 One of the speakers even had a satellite type mounted on top if it.. Only one of them was like this, and I have never noticed it before in any other theater.. Kind of hard to believe that it was a replacement for a damaged speaker, since it obviously was not up to par with the rest, and it is a fairly new theater. So... do you all know what hardware they use? Kinda peaked my interest, as I looked around the theater before the movie started.. Before getting into this hobby, I really took all of it for granted. It made me enjoy the experience more I think..
     
  5. Juan Castillo

    Juan Castillo Second Unit

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    Hey, btw, looking at the Pro JBL website, I noticed that the crossover frequencies recommended by JBL for their Subwoofer lines are from 80 - 150 Hz... isnt that more midrange frequency than subwoofer?
     
  6. Earl J

    Earl J Stunt Coordinator

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    Jeff, I live about 1/2 hour from that Ontario Mills theater. 10-15 18" subs? Wow! It's amazing how far the bass can travel in those theaters when the subs are behind the screen. I remember watching Saving Private Ryan in that theater and was sitting towards the back. The bass was pretty darn good. Hmmm, I wonder what 10-15 SVS Ultra's would be like in the same theater.
     
  7. I don't know about you, but I would want 10-15 BPD1803's in my local theaters=)
     
  8. jeff lam

    jeff lam Screenwriter

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    Ya Ant, then they would need about 15K watts of power but WOW, it will be some serious bass.
     
  9. Jon D

    Jon D Stunt Coordinator

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    I knew a guy who had seen the speaker systems in one of the newer stadium style theaters. He said they had a series of 12" behind the screen and several 15" in the walls and floors. I saw The Phantom Menace there, and I nearly suffered cardiac arrest from the bass.
     
  10. Christian Dolan

    Christian Dolan Stunt Coordinator

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    Juan,

    I was a part-time projectionist for about a year and a half at an 11-plex in Bloomington, IN. I remember that the Dolby and Ultra-Stereo processors make an allowance for external audio (muzak, local radio) to be switched in. This is essentially routed to front L/R.

    As for the satellite,if it was located on the rear wall, it may be a small PA speaker (like to tell the audience that the theater's on fire, etc.). Hope this helps.

    -Christian
     
  11. Dan Hine

    Dan Hine Screenwriter

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  12. Tom Brennan

    Tom Brennan Screenwriter

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    Dan--Good post. Yes, the needs of theater sound systems are high output with low distortion, also directivity control at midrange and high frequencies. Thus the use of high-efficiency, high-output drivers with very low distortion. Good pro-sound is expensive but not that expensive, a single theater main consisting of double 15s in a vented box and a 2" throat compression driver on a constant-directivity horn sells for under $2500; JBLPro or KlipschPro. You can pay that much for audiophile 2-ways with cheap Madisound Catalog drivers. I use 2 JBL 4648-A8 bassbins in my HT, these are the vented double 15 bassbins used in JBL THX mains. Placed at the boundry of wall and floor and given a little EQ (6 db at 30hz) they are flat at 25hz, the lowest reading on my RTA. And the pair is 100db efficient counting the 6db EQ. At full power they are capable of 128.5 db at 25hz, that's counting the EQ and 4.5db of compression at full power (how many speakermakers even dare talk about compression). I use them from 100hz down to augment the bass of my Altec VOT theater speakers. I bought these bins brand new for $220 each (with free shipping no less) from the JBL Pro online tentsale, quite a bargain considering that the 2226 woofers used cost $330 each at Parts Express, that's over $1300 worth of raw drivers in the 2 bins, such a deal, the bins retail for $1300 each. There are still 4638 bassbins, double 15 theater bins but with a little less output, available there for about $216 each, check it out.
     
  13. Dan Hine

    Dan Hine Screenwriter

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    Tom,
    Indeed it certainly does sound like you got some good deals. [​IMG] My guess on the cost of the JBL commercial subs comes from the fact that I know they must be better than the OAP subs I work with and they were $900ish apiece. Great for overall output, not something I would want in my home. I've actually toyed with the idea of building a sub for road use by using a typical DIY driver like a Tempest or Brahma. They would take up less space and cost less, but I would lose some output do to the lower efficiency. It's still up in the air.
    Regards,
    Dan Hine
     
  14. Tom Brennan

    Tom Brennan Screenwriter

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    Dan---Yeah, it never ends, always tradeoffs, no speaker does it all and is easy to move. I was in a band with a bassplayer who used one of those huge Acoustic 370 amps with the folded horn bassbin (I'm dating myself), it made LOTS of bass but was a monster to move. The bin's weak midrange combined with the guy's Gibson EB-3 bass made for more mud than than the Monsoon season, he shoulda worn rubber boots when he played.
     
  15. Keir H

    Keir H Second Unit

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    Another "fun" question: has anyone seen a theater with Bose speakers installed? I saw a magazine ad once with Bose all around for side and rear surround. At least its different than the normal JBL! or Klipsch we see ofter. [​IMG]
     
  16. Thomas_A

    Thomas_A Second Unit

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    No..but the local waterburger (restaurant) has bose in them.. I almost choked on my burger. I was wonder where the sound was comming from..sure enough.. bose! in the ceiling.. anyway..

    the one theater we go to uses the klipsch
     
  17. John Garcia

    John Garcia Executive Producer

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    I was in a JBL THX certified theater in Michigan last year, even with a little intro about the speakers (HLS series). It sounded like complete and utter crap. So bad, I almost walked out. I don't remember the movie, but I remember the horrible sound.

    At an AMC locally, I could acutally hear that they had killed at least one of their subs (or damaged something), because it was rattling very badly.

    Locally, I like the THX Century theaters. Even in the smaller theaters, the sound is good. Now if they could only get some nicer seating...

     
  18. marc seals

    marc seals Agent

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    A friend of mine used to be an assistant manager at the brand new (3 years ago) Century 16 here in Anchorage. I got him to give me a tour of the projection rooms and also check out the subs they used.

    They use JBL subs and had them underneath the stage. In the larger theater the actual sub boxes were huge, though I don't remember any model #'s.

    The projection room tour was pretty cool also. They use QSC for amps and had 6 or 8 of them for one of the larger theaters. Once again I don't remember the models involved.

    All in all an interesting tour though.
     
  19. Tom Brennan

    Tom Brennan Screenwriter

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    Anthony---A theater I go to, The Tivoli in Downers Grove, Illinois, has an HPS 4000 rig. It is the finest theater sound I've heard since the 70mm magnetic track roadshow days when 10 hornloaded Altec 15"s behind the screen was common. Actually I think theater speakers have taken a step backwards with THX. The standard speaker for THX uses a woofer bin consisting of double 15" woofers in vented boxes, I think these sound inferior to the old Altec A series bassbins that used 15"s in combination horn-reflex cabinets. Those Altecs had a warmth and projection I find missing today. But those A4s were VERY large and expensive, easier and cheaper to do simple vented boxes and of course the vented boxes do work very well. Checkout www.voiceofthetheatre.com
     

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