Is it possible to obtain left and right rear corner imaging in a ES/EX setup?

Discussion in 'Archived Threads 2001-2004' started by David Proud, Jan 27, 2003.

  1. David Proud

    David Proud Stunt Coordinator

    Joined:
    Jul 25, 2000
    Messages:
    202
    Likes Received:
    0
    in a 5.1 setup monopole side surrounds are positioned to the sides and slightly behind your ears on the side walls. This provides great imaging for rear left corner, rear center, and rear right corner.

    However when moving up to a ES/EX setup with 2 rear speakers in back of the room they recommend you move your side surrounds up even with your ears on the side walls. This is to improve side imaging. In this config it provides strong rear center imaging when information is dead on back center do to the matrix extraction/channel in the rear of the room, but how would one still be able to get rear left corner imaging and rear right corner imaging with the side surrounds even with the ears?

    Take the patriot for example. with a 5.1 setup and side surrounds slightly behind and to the left there are explosions all across the back of the room in different locations. In back left corner, back center, back right corner.

    With moving to THX-EX and moving tge side surrounds up and only 1 center channel in the back it seems as though my rear soundstage will be shrinking. no more left corner imaging or right corner imaging in the patriot.

    Am I wrong in my assumption that rear steering will be effected?
     
  2. Craig_Kg

    Craig_Kg Supporting Actor

    Joined:
    Feb 25, 2002
    Messages:
    768
    Likes Received:
    0
    It depends on how much of the mix is common to the rear channels. Sounds are rarely exclusive to the left or right rear so a small amount of common material will be matrixed out to the rear centers to steer your perception. The amount will vary from scene to scene in any title but in extreme cases, you may lose the exact corner effect.
     
  3. Marty Neudel

    Marty Neudel Stunt Coordinator

    Joined:
    Mar 16, 1999
    Messages:
    223
    Likes Received:
    0
    David,

    Logic7 will provide separate left and right back channels with EX/ES (as well as without). This effect, however, may not be what the directos/sound-mixer intended for that film.

    Marty
     
  4. AaronBatiuk

    AaronBatiuk Second Unit

    Joined:
    Aug 23, 2002
    Messages:
    333
    Likes Received:
    0
     
  5. David Proud

    David Proud Stunt Coordinator

    Joined:
    Jul 25, 2000
    Messages:
    202
    Likes Received:
    0
    so for a theater with 2 or more rows LOGIC7 is a must for the 2nd row where the side surrounds are in front of them?
     
  6. David Proud

    David Proud Stunt Coordinator

    Joined:
    Jul 25, 2000
    Messages:
    202
    Likes Received:
    0
    ah, logic7 downmixes. man. So what is one to do with 2 rows. The backrow will have the side information 4 feet in front of them on the side walls, does the rear center behind them help that much?

    In my original design I was going to put the side surrounds at 14ft exactly in the middle of the two rows. Now I want the best sound for the back row as well and realize I could really benifit from an ES/EX setup.

    However in going to a ES/EX setup everything I read told me that it is recommeneded to move my side surrounds forward directly to the sides of my main listening row. I am concerned that by doing this I will sacrafice rear soundstage. That is why I asked if in a es/ex setup how well the rear centers steer with the side speakers.

    Take the Dolby Digital Trailer where the flying disc flys over head, rotates back and forth behind you and works its way forward though the back channels up to the front channels.

    Will that trailer be able to image between the left side
    surround and the back centers ie for left back corner placement? If not I don't see how anyone could recommend moving the sides up directly to the side. If so my worries are over,

    If they can I just don't understand how the rear center dirivied from a matrix and sides could be mixed at the same time.
     
  7. Marty Neudel

    Marty Neudel Stunt Coordinator

    Joined:
    Mar 16, 1999
    Messages:
    223
    Likes Received:
    0
    On January 28th, AaronBatiuk posted the following:

    "Be very careful in using Logic 7 on 5.1 sources! The logic 7 algorithm can only be applied to 2 channel sources; the few pieces of equipment that allow it to be applied to 5.1 sources actually downmix to 2 channels first, then apply logic 7 to that. The result, as you said, is most certainly not what the director/sound-mixer intended ."

    I e-mailed Jeremy Frost at Lexicon about this and he responded:

    "this is not accurate.

    The L7 modes for 5.1 and 6.1 sources are very different from the L7 modes designed for 2 CH sources. There is more information to work with in 5.1 and 6.1 sources. Unlike EX and ES, 5.1 L7 and dts L7 can steer sounds between the rear speakers.

    This person may be confusing this with another feature. It is possible to downmix a 5.1 or 6.1 channel soure to 2 channels (at which point it is encoded in L7), record it, and then play it back through an L7 decoder. This is a handy way to retain surround information when recording, for instance, from a satellite onto a PVR like a Tivo unit.

    Jeremy"
     

Share This Page