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Author Topic: Speakers behind screen vs. around screen question. Ray Bernardi Expert Film Handler Posts: 120 From: Antrim, NH, USA Registered: Feb 2003 posted 04-10-2003 08:00 AM                     I've learned a lot here. I thank you all. I'd like to ask a question. I own a small theatre that has a lousy sound system. I'm going to upgrade it. I have a large screen curved set into the back wall. No way to put a screen array behind it. I have room on the left, the right, above and below inside the wall for speakers. My thought was to put the new speakers in the wall. Left and right are obvious. I'd put the center channel on top angled down at the audience. The subwoofer would go on the bottom of the screen. I've mentioned doing this to the folks who are going to do the work for me. They suggest I put up a new sound screen in front of my old screen and place the speakers directly behind it. I know the new screen would give me a brighter picture, but does it really matter if the speakers are directly behind it or just around it as I propose? Please give me your feedback. I really want to do this once, and do it right. Thanks guys and gals.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 04-10-2003 08:46 AM                     AMC installs their speakers above the screen in the installations that use the curved compound screen. Its quite obvious that the sound is comming from ABOVE the screen in those places. Installing a new screen and installing the speakers behind it would be the correct way to do this....can't you just get rid of the old screen all together, or move it slightly out from the back wall? If that screen is really bad it should be replaced anyway. Your customers WILL appreciate any improvements you do there!! Generally screen frames are not "nailed in place" so to say...sometimes flown though and that might be a limitation if that is the case....or then just get rid of it. Mark @ CLACO  |  IP: Logged Mark J. Marshall Film God Posts: 3188 From: New Castle, DE, USA Registered: Aug 2002 posted 04-10-2003 08:51 AM                    This may be a stupid question, but I have to ask... Is the current screen perforated? And where are the current lousy speakers?  |  IP: Logged Ray Bernardi Expert Film Handler Posts: 120 From: Antrim, NH, USA Registered: Feb 2003 posted 04-10-2003 02:13 PM                     The current screen is made of sheetrock. It's curved. yes you can curve sheetrock we've already covered that in a previous thread! It's built right over the back wall - it's actually the back wall itself. There is no behind it, it's not perforated at all. The current crappy speakers are on either side of the screen. Mono - no left no right no center no sub no surround - it's basically a 20 watt PA system with two speakers hooked to it. I gotta tell ya, Chicago sounded like CRAP! I know I need to do something. Putting up the perforated sound screen adds 1K to the project. I was hoping I could cut that corner a bit.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 04-10-2003 02:34 PM                        Unless the screen is really small, the sound will not seem to come from the image unless the speakers are behind a perforated screen. A unique solution might be to REFLECT the sound from the solid screen by aiming the speakers at the screen, but that is a phasing and equalization nightmare.  |  IP: Logged Bob Koch Expert Film Handler Posts: 183 From: williams ca Registered: Nov 2001 posted 04-10-2003 03:12 PM                     If the speakers are not where the action is it`s disaster.Try closing your eyes while listening, when the speakers are not in their proper location with dialogue and you`ll see that you don`t want to use a weird location.  |  IP: Logged Mike Blakesley Film God Posts: 12767 From: Forsyth, Montana Registered: Jun 99 posted 04-10-2003 05:37 PM                        I vote replacement. Your customers will be thanking you for years. People care more about sound than they let on, especially in small locations.  |  IP: Logged Don Sneed Master Film Handler Posts: 451 From: Texas City, TX, USA Registered: Aug 2001 posted 04-10-2003 06:42 PM                        I been to several AMC theatres using EAW speakers, with the hi-freq. located above the screen & the woofers on the floor, I was impress with the sound quailty & thought it was a good idea...but I would hate to be the poor tech that has to get up to the hi-freq. cabinet to replace the voice diapham...exspecially since I'm scare of hieghts...(I have a man to do all my speaker connections, repairs, & speaker aiming...  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 04-10-2003 09:15 PM                        Just seems obvious that the sound should come from where the actor's mouth is, or therebouts. Don't know that one could ever get quite used to movies, featuring a cast of ventriloquists! Don't feel too bad about the lousy sound system... at least you've recognized you have an issue that needs dealing with. I once saw an indoor house that had reasonably good equipment right up to the amplifier.... which was a Bogen CHS series PA amp, mounted right under the observation port!  |  IP: Logged Michael Schaffer "Where is the Boardwalk Hotel?" Posts: 4143 From: Boston, MA Registered: Apr 2002 posted 04-10-2003 09:50 PM                        quote: Just seems obvious that the sound should come from where the actor's mouth is, or therebouts. Since we don`t get treated to directional mixing anymore, that`s what we see/hear a lot of times anyway. But that`s a different subject... I know the technical manager of a North European chain, and they install all their cinemas with the speakers above the screen aimed steeply downwards. I will contact him about details.  |  IP: Logged Philippe Laude Film Handler Posts: 79 From: Longueville, Belgium Registered: Jul 99 posted 04-11-2003 02:21 AM                     I totally agree with Mark. Ray don't forget that when you bring your essential new screen closer to the projector, you"ll need to change your lenses too. Another unexpected expense! Your audience will just love you. Philippe  |  IP: Logged Lindsay Morris Expert Film Handler Posts: 233 From: Darlington, WA, Australia Registered: Sep 2002 posted 04-11-2003 05:07 AM                     Ray, I have a similar problem being an outdoor screen, made of steel and certainly NOT perforated so when I set my system up I followed what an dear friend of mine did some years ago at his outdoor which had a brick screen and was about 45feet wide. He put his HF unit on top and his Bass boxes, a pair of 15" drivers either side of the screen. Sound was magic but of course that was in mono days. I am basically mono with a bit of simulated stereo fed into a column speaker unit hung on either side of the screen. In my case I have mounted the HF Horn (which is now a Raycophone unit and has a field coil requiring 10volts to energise it... so it is VERY old) right on top of the screen angled down so the centre of the multi-cellular throat points into the middle of the audience. The bass unit with 2 x 15" drivers, powered 80watt subwoofer, 400Hz Crossover plus HF field coil power supply are all in the one big "W" bin at the base of the screen. It is something like 7 metres from bass unit up to HF horn and the sound is quite OK. It all blends nicely and there is no perception that the sound is coming from the top or the bottom of the screen it seems to spread out and merge very well. The original horn, a Vitavox had 8 throats and for 6 years that worked OK until zapped by lightning one night. The replacement Raycophone is probably a 1940's era of manufacture and has 16 throats and if anything is far superior to the Vitavox in terms of spreading the sound and the clarity of its output. We seat 310 and have had 500 some nights for Big Fat Greek Wedding and if I feed about 5watts down the line it is VERY loud.(Very efficient units they made in those days) So if your setup is phased OK I do not think you will have much problem having the HF unit on top. When I set mine up I wired a reversing switch into the HF line and with some music going had a helper at the base of the screen switch the reversing switch each time I raised my hand. I was really battling to pick which way round was the best in terms of phasing between the HF and LF units. Even going to voice from a radio source still did not alter the clarity which ever way I set the connections. I think phasing is more important for LF efficiencies as due to the frequency those cones have to shift more air for people to hear it effectively and if you connect a couple of woofers out of phase you soon can pick that up. Possibly the phasing of the HF to LF units is more critical indoors than outdoors... never had to tinker with indoor setups. I hire a cherry picker to check and service the HF horn each season as it sits up there all year round, rain hail or shine but it's driver is well covered in plastic and canvas to waterproof it and has a heavy duty gauze over the face to prevent insects building nests in the throats.. wasps love those little tunnels. I would just try it out and see what works best... shifting that screen would be like me having to shift mine... not likely with 3 x 100mm steel legs set in concrete. I may be in for a surprise this winter as I upgrade to stereo and surround sound but I have nowhere else to put the speakers so it will an interesting when I get "true" stereo going to see what it all sounds like then! Lindsay  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 04-11-2003 07:30 AM                        quote: Ray don't forget that when you bring your essential new screen closer to the projector, you"ll need to change your lenses too. Another unexpected expense! Just get a bigger screen when you move it forward! edit: Now that I'm awake... your moving the screen back towards the lens, not forward. It's going to get smaller. You know, new lenses would be nice though. [ 04-11-2003, 10:31 AM: Message edited by: Daryl C. W. O'Shea ]  |  IP: Logged Ray Bernardi Expert Film Handler Posts: 120 From: Antrim, NH, USA Registered: Feb 2003 posted 04-11-2003 07:33 AM                     New lenses? I didn't think the screen was going to move that far. The new screen would only be about 20 inches closer. It would make that big a difference? Hmmmm. How much bigger a screen would that require? I like the idea of a bit bigger picture....... but...... I'm starting to think that I'll try it with the old screen first. Put the speakers in the wall and do the best that I can with it. If I'm not happy with it when it's all done, I can always put up the sound screen later. What should I paint the old screen with to make it really reflective? Any suggestions? +++++++ Scratch all above ---- +++++++ Here we go - I'm going to do the new screen. I'll make it bigger so I don't need to change the lenses. I'll mask it doing a pipe and drape deal around it. All material up to fire code. The screen array goes behind it. I'll have a center, left, right and a single subwoofer back there. Two surround sounds on the left wall two on the right wall. All new in the booth, processor, amps, sound head, reader etc.... The plan is to have this accomplished within 3 weeks from now without stopping business to do it. Keep giving me ideas please. You've all been very helpful. I'll be taking some before and after pictures of the auditorium and the booth as I do this. I'll post them when I can so you can see how much fun I'm having. Who the hell knew this much went into showing a damn movie? I sure didn't when I got this business. It's been an education I tell ya.......  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 04-11-2003 08:45 AM                        Moving the screen closer to the projector will result in a SMALLER image, or require a shorter focal length lens to keep the same image size. Use one of the on-line lens calculators: http://www.schneideroptics.com/software/ http://www.iscooptic.de/english/downloads/indexdown.php  |  IP: Logged

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