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I need 5.1 surround circuit

Discussion in 'General Electronics Chat' started by carloscapitao, May 9, 2004.

  1. carloscapitao

    carloscapitao New Member

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    :D Hy, I need circuit, diagram, schematic 5.1 decoder system.

    I have surround theory, but with one surround channel output.

    I want 5.1 sistem whit two surround channel output , Ls and Rs.

    Help me

    thanks

    Carlos
  2. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Dolby 5.1 is a digital system (used on DVD players and digital satellite receivers), presumably all you need is the correct I/C (and all the support components), for which you have to pay Dolby a licence fee.

    I would have thought it's totally impractical to try and build one, you can buy DVD players and amplifiers with Dolby 5.1 built-in for very little money.
  3. carloscapitao

    carloscapitao New Member

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    5.1 surround discrete system

    In dolby site there is all about surround sound system and because this
    I could project, to build and to set up with success a prototype.

    I sought information about 5.1 system but they are superfluous and I could not project an appropriate system.

    I am sure that as soon as I discover the origin of the channels Sr and Lr I can project a circuit with great efficiency.
  4. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Re: 5.1 surround discrete system

    As far as I know they are simply individual channels in the digital data stream - which is why it can have two rear channels, and the analogue Pro-Logic can only have one.
  5. olly_k

    olly_k Member

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    Before I could afford a decent surround amp - in the days when even dolby surround processors seemed expensive (never mind pro-logic!) I connected a pair of speakers in series between the two 'right' output terminals of my amplifier's 'speakers b output'. i.e. nothing connected to the negative terminals.

    I then switched the nicam and channel 'a' speakers off (mono sound, no front speakers) to balance the L+R channels until I could here minimum sound from the rear speakers. this was accomplished through VCR and amplifier balance controls.
    This left me with rear speakers that only displayed left and right information and gave a very atmospheric surround effect! Surround sound which in my opinion was as good as the sherwood pro-logic amp I purchased a few years later!
    I think that is possibly one of the more realistic approaches to making your own surround setup because as Nigel implied, Dolby are very protective over the technical details of their surround systems.
    Even if you could get hold of the processors, making even a simple circuit would be no simple task!
  6. sumon

    sumon New Member

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    where is the circuit diagram
  7. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Connecting the rear speakers in series and to both hot terminals of the stereo amplifier is The Hafler Method of cheap and simple surround sound. it was invented in the early 70's. I used it with vinyl records. Its front to back separation is very low but it is audible.

    Attached Files:

  8. harishece86

    harishece86 New Member

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    how design doubly digital pro logic board and wish component will you to design the doubly system
  9. audioguru

    audioguru Well-Known Member Most Helpful Member

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    No speaky zee English?
  10. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    Here you go! Good luck building one! :)

    Attached Files:

  11. tifahot

    tifahot New Member

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    thank you very much
    but , i want how can control this ic [ NJW1107FC3 ] and [ NJU26108 ] and all functions



    thank you very much
  12. crutschow

    crutschow Well-Known Member Most Helpful Member

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    You read and follow the data sheet information.
  13. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Are you Japanese? Very few if any of us use those old obsolete Japanese ICs.

    I bought my daughter a sound system with old Dolby Pro-Logic for her 16th birthday 14 years ago. Dolby Pro-Logic is not used today.
    Now they use Dollby Digital Surround Sound.
    I think the mono-to-stereo or to-surround is Mickey-Mouse because you cannot make stereo or surround sound from mono.

    You can probably control those old obsolete Japanese ICs with a microcontroller.
    Last edited: Jan 1, 2011
  14. kecik

    kecik New Member

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    i want to do the simple surround sound..
    how can i got the schematic.?
  15. audioguru

    audioguru Well-Known Member Most Helpful Member

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    The simplest "surround sound" system was the Hafler circuit. It produced very little front to back separation.
    Here is an article about the Hafler surround sound circuit: http://sound.westhost.com/project18.htm
    The first one has 3 channels: left front, right front and rear. It uses only a stereo amplifier and 4 speakers.
    The second one uses 6 amplifiers and 6 speakers.
  16. kecik

    kecik New Member

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    ok thank you.
    so,how about surround schematic use 6 amplifier and 6 speakers?
  17. unclejed613

    unclejed613 Well-Known Member

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    there's also a way of using op amps to do addition and subtraction. first you buffer the R and L inputs, as well as feed them into gain of 2 op amps. you now have the following signals: L, 2L, R, 2R. for center channel, sum L+R. then you need to subtract some signals with a diff amp. for L front, use 2L-R, for right front use 2R-L. for the rear channels: Surround L is L-R, surround R is R-L. it's sort of a modification of the Hafler surround, but gives more defined channel separation. and it's all done with op amps.
  18. audioguru

    audioguru Well-Known Member Most Helpful Member

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    It is a very simple circuit in the article I linked to. It uses 6 power amplifiers. Since it is very simple then the front to back and L to R rear separations are very poor. I copied it here:

    Attached Files:

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