Surrounder Explained

Discussion in '3-D Audio' started by ROBSCIX, Sep 4, 2004.

  1. ROBSCIX

    ROBSCIX New Member

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    I found some people are unclear as to certain values in surrounder. I will explain these settings as I have come to understand them.
    Speaker Mode: Set to speakers you have. e.g 2.0, 4.1, 5.1..etc.
    Surround: On...Enables balancing of surround parameters.
    Surround: Off...Disables surround sound.
    Surround: Copy....Allow Rear front and rear channels to receive same signal.

    VCenterA: The Amount of signal to the CENTER channel on a 5.1 system.
    VRearA: The Amount of signal to the REAR channels.
    VRearW: The Width of your REAR channels.
    VRearD: The Amount of signal Delay between front and rear channels.

    Use Subwoofer: Enables Discrete subwoofer output, if you have one.

    Enable Bass Redirection: Enables crossover frequency adjustment for the subwoofer channel.

    Split Freq: The Frequency (Hz) at which crossover starts to filter signals to subwoofer channel.

    Change your settings to get best possible surround sound imaging. Use Bass Redirection and split freq to get the most natural sounding bass response. Of course you just set them to what sounds good on your system in your space to you.

    Hope that helps.
     
    Last edited: Aug 28, 2005
  2. dj_stick

    dj_stick Apple Fanboy?

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    you sound right, and yup sticky
     
  3. Max M.

    Max M. h/h member-shmember

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    probably, you'll find following info to be useful too
    (these are some details about first version of surrounder - written 25.02.03
    - something may be changed since)

    :
    Code:
    signal paths:
    
    spk:2.1, sur:off
    ----------------------
    L  -------> fL
    R  -------> fR
    fL -------> fL
    fR -------> fR
    sL -------> sL
    sR -------> sR
    sC -------> sC
    
    spk:2.1, sur:copy
    ----------------------
    L  -------> fL
    R  -------> fR
    fL -------> fL
    fR -------> fR
    sL -------> sL
       `------> fL
    sR -------> sR
       `------> fR
    sC -------> sC
       `------> fL
       `------> fR
    
    spk:2.1, sur:on
    ----------------------
    L  -------> fL
    R  -------> fR
    fL -------> fL
    fR -------> fR
         ___
    sL -|   |-> fL
    sR -|   |-> fR
    sC -|enc|-> sL
        |   |-> sR
        |___|-> sC
    
    
    spk:5.1, sur:off
    ----------------------
    L  -------> fL
    R  -------> fR
    fL -------> fL
    fR -------> fR
    sL -------> sL
    sR -------> sR
    sC -------> sC
    
    spk:5.1, sur:copy
    ----------------------
    L  -------> fL
       `------> sL
       `------> C
    R  -------> fR
       `------> sR
       `------> C
    fL -------> fL
    fR -------> fR
    sL -------> sL
    sR -------> sR
    sC -------> sC
    
    spk:5.1, sur:on
    ----------------------
         ___
    L  -|   |-> fL
    R  -|   |-> fR
        |dec|-> sL
        |   |-> sR
        |___|-> sC
    fL -------> fL
    fR -------> fR
    sL -------> sL
    sR -------> sR
    sC -------> sC
    
    
    spk:4.1 - same as 5.1 except Center as in 2.1
    
    ---------------------------------
    phisical meaning of sur controls:
    ----------------------------------------------------------------------------------
              |         2.1           |          4.1          |          5.1          |
    ----------------------------------------------------------------------------------
    VCenterA  | C to fL/fR amount     | C to fL/fR amount     | L/R to C amount       |
    VRearA    | sR/sR to fL/fR amount | L/R to sL/sR amount   | L/R to sL/sR amount   |
    VRearW    | width of encoded rear | width of decoded rear | width of decoded rear |
    VRearD    |         n/a           | delay of decoded rear | delay of decoded rear |
    
    So.. ok, in other words:
    Sur:Off  - means "What you hear is what you play"
        (e.g. "normal" mode - nothing happens with the sound except mixing L/R into fL/fR)
    Sur:Copy - "You hear everything you play with all of your speakers"
        (e.g. "dummy heads" mode)
    Sur:On - same as Copy with ~phase encoding/decoding applied
        (e.g. "dumb heads" mode)
    
    
     
  4. Rswave2k2

    Rswave2k2 New Member

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    wow thanks for the help and the sticky.
     
  5. Russ

    Russ Well-Known Member

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    Here is an updated version of Max's routing diagram. It is almost the same, except that it uses the current input/output names, and the 2.1 modes appear to be a little different. The diagram is based on the code used in Surrounder+.

    Note that the diagram does not show the Bass Redirection stuff.

    Code:
    spk:2.1, sur:off
    ----------------------------
    inL    -----|-> fL
    in_nw  -----|
    
    inR    -----|-> fR
    in_ne  -----|
    
    spk:2.1, sur:copy
    ----------------------------
    inL    -----|-> fL
    in_nw  -----|
    in_sw  -----|
    in_n   -----|
    
    inR    -----|-> fR
    in_ne  -----|
    in_se  -----|
    in_n   -----|
    
    
    spk:2.1, sur:on
    ----------------------------
             ___
    inL    -|   |
    in_nw  -|   |-> fL 
    in_ne  -|   |
    in_n   -|enc|
    in_sw  -|   |
    in_se  -|   |-> fR 
    inR    -|___|
    
    spk:5.1, sur:off
    ----------------------------
    inL    -----|-> fL
    in_nw  -----|
    
    inR    -----|-> fR
    in_ne  -----|
    
    in_sw  -------> sL
    in_se  -------> sR
    in_n   -------> Center
    
    spk:5.1, sur:copy
    ----------------------------
    inL    -----|-> fL
    in_nw  -----|
    
    inR    -----|-> fR
    in_ne  -----|
    
    inL    -----|-> sL
    in_sw  -----|
    
    inR    -----|-> sR
    in_se  -----|
    
    inL    -----|-> Center
    inR    -----|
    in_n   -----|
    
    spk:5.1, sur:on
    ----------------------------
             ___
            |   |-> fL 
    inL    -|   |-> fR
            |dec|-> sL
    inR    -|   |-> sR
            |___|-> Center        
    in_nw  -------> fL
    in_ne  -------> fR
    in_sw  -------> sL
    in_se  -------> sR
    in_n   -------> Center
    
    LFE input/output works as follows (not including Bass Redirection stuff):

    The LFE output is only used when "Use Subwoofer output" is enabled. In this case, LFE Out = LFE In, with no mixing of LFE into other channels.

    If "Use Subwoofer output" is disabled:
    If Surround is OFF, LFE input is not used, otherwise:
    In 2.1 Speaker mode, LFE input (half) is subtracted from the resulting downmix.
    In all other speaker modes, LFE input (half) is subtract from inL/inR, and the result is used for upmixing/downmixing.
     
    Last edited: Jan 16, 2008
  6. Russ

    Russ Well-Known Member

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    Input/output names
    -------------------

    L/R are the generic left/right inputs.
    Input here is upmixed according to Surrounder's settings.

    N/S/W/E/NW/NE/SW/SE = Directional indicators like those found on a
    compass (except 'N' is always directly in front of you).

    fL/fR = Front Left/Right
    sL/sR = Surround/Rear Left/Right
    Center = Center (front)
    LFE = LFE

    6.1 Mode:
    sCenter1 = Rear Center

    7.1 Mode:
    sCenter1 = Side Left
    sCenter2 = Side Right

    Code:
    fL · · · · · ·  C  · · · · · · fR
    ·                               ·
    ·               N               ·
    ·      NW       ·       NE      ·
    ·         ·     ·     ·         ·
    ·           ·   ·   ·           ·
    ·             · · ·             ·
    ·     W · · · · + · · · · E     ·
    ·             · · ·             ·
    ·           ·   ·   ·           ·
    ·         ·     ·     ·         ·
    ·      SW       ·       SE      ·
    ·               S               ·
    ·                               ·
    sL · · · · · · · · · · · · · · sR
    
     
    Last edited: Dec 3, 2007
  7. brainless_beginner

    brainless_beginner is so brainless..

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    Is it possible somehow to have really stereo surround? i mean left surr and right surr separately
     
  8. Russ

    Russ Well-Known Member

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    I am not sure what you mean, sL and sR and separate. The only mixing between the two (IIRC) is from the rear width setting (VRearW). If you do not want any mixing, then set VRearW to 0.
     
  9. brainless_beginner

    brainless_beginner is so brainless..

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    i mean when VRearW=1 the sounds from sl and sr speakers are the same (kinda mono from both)
     
  10. brainless_beginner

    brainless_beginner is so brainless..

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    i guess it's achived by substracting L from R or vice versa resulting in

    L-R=SL-SR or
    R-L=SL-SR

    i mean to have only SL from SL spk and SR from SR spk
     
  11. Russ

    Russ Well-Known Member

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    Right, that is how width works.

    i.e. (rear: (W)idth, (A)mount, and (D)elay settings are used something like this)

    sL = VRearD_Delayed ( (inL * VRearA) - (inR * (VRearW * VRearA)) )
    sR = VRearD_Delayed ( (inR * VRearA) - (inL * (VRearW * VRearA)) )

    So again, set VRearW to 0, if you do not want that behavior.

    BTW: Those settings only effect upmixing/downmixing.
     
    Last edited: Feb 22, 2011
  12. WxMan1

    WxMan1 Active Member

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    :hmm:

    Not seeing these settings in Surrounder (v3541 - debug) having any affect on sL, sR, or CENTER output when doing SPEAKER TEST.

    When performing SPEAKER TEST, PEAK indicates -13.6dB and -Inf output level from Surrounder+ sR / sL whether VRearW is 1 or 0; the output levels of the specific Surrounder+ sChannels are appropriate to the specific sChannel being tested. Moreover, whether VRearA is 1 or 0, SPEAKER TEST results in the same -13.6dB output levels appropriate to the sChannel being tested, albeit output signal fluctuatation can be observed in accordance to the source program from Media Player input. However, in either case, no affect can be discerned by any changes either VRearA or VRearW (either independently or concurrently).

    Nevertheless, even so PEAK indicates the same -13.6dB Surrounder+ CENTER output level whether VCenterA is 0 or 1 when performing SPEAKER TEST, it does have an affect if Media Player is the source, i.e., VCenterA at 0 results in -Inf output level observed from Surrounder+ CENTER output by PEAK.

    :confused:

    This on a CT4780 (10k1) set to 5.1 in WinXP & in Surrounder+.

    POSTSCRIPT: additional testing has revealed that VRearA has only the affect of influencing VRearW. When VRearA is set to 0, then VRearW is absolutely without affect. When VRearA is some non-zero value, then VRearW has the affect of establishing the degree of mono the rear channel signal with respect to VRearA.

    When VRearA is 0, the only difference betwixt the front & sChannels signal then would be with respect to the delay that VReadD imparts upon the front channel stereo signal. If, however, VRearD is 0 then the only intrinsic difference would be any difference in gain - if any - the sChannels inherently have with respect to the front stereo channels, i.e., with VRearA and VRearD set to zero the Surrdounder+ SURROUND mode is essentially set to "copy".

    This affect is very easy to demonstrate by plugging in headphones into the correct "rear" speaker jack. With VRearA set to 0 the sound is essentially two-speaker stereo. However, when VRearA is increased to 1, then maximum head-phone quality sound can then be discerned with VRearW set to zero. Subsequent increases in VRearW increases a perceived magnitude of "centerness" to the sChannels; essentially a psuedo sCenter.
     
    Last edited: Nov 18, 2008
  13. Max M.

    Max M. h/h member-shmember

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    Îòâåò: Surrounder Explained

    The answer is given by Russ right above:
    p.s.: for the rest (e.g. VRearA/VRearW/VRearD relationship) - see the table in the end of post #3 - i believe it explains that all (not counting older names for input channels it uses)
     
    Last edited: Nov 18, 2008
  14. WxMan1

    WxMan1 Active Member

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    Yeah, I get it now. :D

    The source used for SPEAKER TEST is not appropriate for configuring surround speakers though (per the first part of my previous post). :x

    Furthermore, the PEAK signal level was quite misleading with respect to VRearA and VRearW. This lead to my initial post. :wtf:

    However, the key was in that PEAK showed VCenterA did affect CENTER output from Surrounder+ with Media Playour source. It was this that caused me to listen to the sChannel from Media Player source with head-phones that I discerned what was actually happening. :cool:

    Nevertheless, even with head-phones, there's no discernable difference on sChannel between VRearA 0 or 1, or VRearW 0 or 1 when the source is SPEAKER TEST. :duh:
     
  15. Russ

    Russ Well-Known Member

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    Right, the speaker test audio is not subject to upmixing because it is positional audio (i.e. like 3D audio in games, etc).
     
  16. GP500

    GP500 New Member

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    I thougth i could find it out in surrounder, but i can't get it to work.

    for the mic setup is used this: kX Project: Knowledgebase: kX Getting Started Guide - Microphone Setup

    That's oke.

    Win7 with a ct4832 10k1. sb live! 5.1 sort off.


    I would like my front and rear to give the same output so i can use my headset or switch on my speakers.

    i used all the 2.0 and 4.0 settings and copy features.
    The only thing that happens is that the sound picked up by the mic is given out on the speakers. :x
     

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