Finding extra surrounds

Discussion in 'Speakers' started by andySu, Jul 15, 2006.

  1. andySu

    andySu Cinematographer

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    Last night I heard a sound on the split-surrounds-EX, Star Wars Episode 3 Revenge of the Sith, 2005, that made me think it was placed between channels right-side-surround and centre-back-surround, now to get the surrounds to literally “circle” you will need two matching “matrix decoders” for this technique to work, and matching surrounds, pretty much the same approach as I have taken, at least my surrounds are ready for any improvement.

    So how do I get connected, firstly decoder “A” needs to have the “right output” from the split-surrounds connected to the “right input” the centre back needs to have a (Y) lead connected to the “centre back output” and this needs to be connected to the “left input”.

    The outputs from this decoder will then go to the matching amplifiers and matching surrounds, first output to “right-side-surround” this will be the common “front right” which is assigned to run the “right-side-surrounds”, the “centre-front-output” will go to the two matching surrounds placed on the back wall and placed near to the corners. This is where the new signal will be placed and heard!

    The left font output, will go to the “center-back-surrounds” this is will still sound the same, with a slight difference, don’t worry it will still “knock your soaks off”.

    Decoder ”B“ send the outputs from left split surround to the “left front input” and the “centre back output” connect this to “front right input” now connect the “front left output” to the “left-side-surrounds” and “front centre output” to the two matching surrounds placed on the back wall and placed near to the corners. This is where the new signal will be placed and heard!

    Note: the use of an SPL db metre is required for the set-up and calibration of the new surround array!

    Setting the levels for “playback” use “wideband” “pink noise all channels” turn off the fronts, “center-back-surround” also.

    Now playback the “wideband pink noise” by turning decoder “B” off, or bypass the output mode, set the decoder “A” in “none Dolby” mode, you should hear sound coming from the “right-side-surround” array, set to a comfortable level, (75dbc).

    Now set the level for”centre-back-surround” on decoder “A” for (75dbc)

    Now turn off the amplifier driving the “right-side-surrounds” and turn the “Dolby Pro-Logic” and adjust the center front level for a comfortable level of (75dbc) whilst playing the “wideband pink noise” you should hear it coming from the (new surround position) “left corner”, set the level for “75dbc”.

    Now turn the amplifiers off or the speaker output for “right-side-surround” and set the decoder in “bypass mode” you will hear the “wideband pink noise” coming from the “centre-back-surround” and set the level for 75dbc). Now that levels have been set, or partly done, as an EQ will finalize it all, addressing for slight errors in the frequency response, to the listening position.

    Turn decoder “A” off or bypass the settings, now turn decoder “B” on and will go though this again, turn the amplifier that drivers the “centre-back-surround” to off or bypass the speaker output settings, now play the “wideband pink noise” and set the “left-side-surround” for a comfortable level of (75dbc) now set the decoder “B” to “Dolby Pro-Logic” and adjust the center front level to get a comfortable (75dbc) you should hear it coming from (new surround position) “left corner”


    Now if you what to finalize the whole new multi surround array, you will need “matching graphic equalizers” to get it done right and an (RTA) to see the peaks and dips in the frequency response.

    Now have some good listening fun with this new surround set! And may the force be with you!
     
  2. andySu

    andySu Cinematographer

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    Now I will be looking into this a lot more over the weeks, and trying out films with split-surrounds, it’s rather incredible that split-surrounds have been around us sine Superman the Movie 1978, whooshed around the cinema 28 years, and yet I’m looking for more ways to get some of the information out of the “split-surrounds mix” and push it to the limits!

    Whilst reading an old article, I have just come up with another “wow idea” as soon as I can get the other JBL Control 1 surrounds installed for the ceiling, I’ll add a few features that will enable me to switch this extra signal to ether the “rear corner sides” or an array placed along the ceiling.

    I’ll keep you updated.
     

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