6.1. Lets clear up any confusion.

Discussion in 'Archived Threads 2001-2004' started by Geoff S, Jul 13, 2002.

  1. Geoff S

    Geoff S Stunt Coordinator

    Jun 1, 2002
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    Used to be I would hear Dolby Ex 6.1 and DTS ES 6.1 were out, and I read that it used a center surround back speaker to improve the entire surround effect dramatically in theaters, and since 2000 in the home. Now that I'm getting a 7.1 receiver I'll have the option to go 6.1/7.1 in the future (but not now, no room for SB speakers yet). I like to have total understanding of these things before moving onto them.

    But exactly how does it work? I've been reading a little on this but I want to make sure I have it right... so here it is:

    Dolby Digital EX (THX Surround EX) is it...

    A). A 7 channel encoding (6.1) that adds the surround back channel to the mix, thus increasing the 384, or 448 kbps bitrate to something higher?

    B). A 5.1 format that has a special remix on the two surround channels that can be matrixed into 6.1 without having to increase the bitrate.

    C). Geoff... you're totally off, or just a little off... what it really is is *(your answer here)*

    As for DTS ES I think I understand it. There is DISCRETE that is a true 6.1 and would slightly increase the 768kbps or 1.5mbps bitrate a little. and DTS EX MATRIX being that encoding on the surround speakers to derive the 6th surround back channel from. Right?

    In theory, with the higher bitrate, and being fully discrete, wouldn't DTS ES Discrete be the best quality for a 6.1 system?

    Also, with a 6.1/7.1 system, a standard 5.1 mix can be matrixed to fill all speakers, correct? So how does this sound?

    Thanks for the clarification. I just like to make sure and have all the facts. Any additional details would be nice too.
  2. John Garcia

    John Garcia Executive Producer

    Jun 24, 1999
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  3. ThomasL

    ThomasL Supporting Actor

    Mar 13, 2001
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    The 6th channel in DD-EX and DTS-ES matrix is a matrixed channel which is "piggybacked" in the L and R surround channels. With DTS-ES Discrete, the 6th channel is a discrete channel. DTS has been able to do this, I believe, by using unused "space" in the bitstream to "squeeze" the 6th channel into the current standard (i.e. the same bitrate, etc.). Any disc that is DTS-ES Discrete is also DTS-ES Matrix so when played back using a DTS-ES Discrete decoder, the "matrixed" portion in the L and R surrounds must be removed. So, in reality, it is also not a true 6.1 discrete format since the L and R surrounds are not "pure" discrete channels.

    Finally, yes, a 5.1 mix can be played back using one of the above decoders. Your mileage may vary. I personally watch 5.1 movies using either DD or DTS decoding and only use the DD-EX or DTS-ES decoders when I'm actually watching a movie that has such a mix on the dvd. There is an excellent list in the Software section of the forum of all the DD-EX/DTS-ES discs that are currently out. I usually check there to see if a movie I'm renting is mixed in one of those formats before I watch.

    hope this helps,


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