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Author Topic: Speaker Placement Carlos Villalpando Film Handler Posts: 21 From: Villa de Álvarez, Colima, México Registered: Jan 2013 posted 02-09-2013 12:18 PM                     Hi to everyone! I had this question in my head for a while, so I decided to post it in here. I don't know if it's in the right forum, but I don't think there's a "sound forum" xD, and since most of the screens are Digital, I thought this one could be the right forum. I've visited all complexes in the city and I've noticed something: In some theatres (Cinépolis) the R and L speakers are in a distance were you can notice the sounds coming from the sides of the screen, but not too far to the edges. In other complex (a local city enterprise) the R&L are so to the sides that you can sometimes mistake them for the surrounds, for example, loud music from a trailer coming way from the sides. And in other complex you don't even notice them! So, my question is: ¿How far to the sides of the screen is the ideal spot to put the R and L speakers?  |  IP: Logged Marcel Birgelen Film God Posts: 3357 From: Maastricht, Limburg, Netherlands Registered: Feb 2012 posted 02-19-2013 06:55 PM                     Have a look at the picture here. That picture represents about the optimal placement for THX certified rooms with three front channels (LF/CF/RF). The big box in the bottom center is obviously the subwoofer. Even with good equipment, for the end effect, not only the placement of the speakers is important, but also the characteristics of the room and the equalization of the audio system. What you can also see on that picture is the baffle wall around the speakers. That helps (amongst other things) to smooth the transition between the separate channels, so you cannot pinpoint the exact location of the speakers that easily. Baffle walls are mandatory for THX certified theaters, but are also often applied in theaters without certification.  |  IP: Logged Mike Blakesley Film God Posts: 12767 From: Forsyth, Montana Registered: Jun 99 posted 02-20-2013 12:10 PM                        In the picture, what is the purpose of the two "indented"-looking areas on each side of the center channel?  |  IP: Logged Ian Freer Expert Film Handler Posts: 135 From: Wellington, New Zealand Registered: Oct 2003 posted 02-20-2013 04:11 PM                     quote: Mike Blakesley In the picture, what is the purpose of the two "indented"-looking areas on each side of the center channel? It looks like this was originally a 5-screen channel set up but LC and RC have been removed?  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 02-20-2013 04:36 PM                     Instead of making cutouts in the baffle wall and setting the speakers in the resulting alcoves, the speakers were set in front of the baffle wall and pieces were put around the front of them.  |  IP: Logged Jarod Reddig Jedi Master Film Handler Posts: 513 From: Hays, Ks Registered: Jun 2011 posted 02-20-2013 10:57 PM                     Yes I agree with Randy.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 02-20-2013 11:42 PM                     If side adjustable maskings are used: the L/R were placed within the FLAT masking tabs. On unmasked screens, the L/R were place more outward towards the edge of the screen.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 02-21-2013 07:10 AM                        The baffle wall has little or no effect much below the crossover frequency. Best effect is 100 Hz or below. Yes, it is important but not exactly for the reason that thx says. Louis  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 02-21-2013 09:32 AM                       Marcel, The idea of the THX wall was to pinpoint the channel separation nut blur it. Among many other benefits the wall keeps backstage echos, mostly mid and lower frequencies, from getting though between the speakers and blurring the precise location. The padding on the front of the wall soaks up the HF bouncing off the back of the screen, for the same purpose; to sharpen the separation, not blur it. If there are to be sounds located between channels, it's the mixers job to place them there during the mix. This has been covered a number of times on this forum.  |  IP: Logged

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