Stereo Circuit Help Required Urgently.

Discussion in 'The Projects Forum' started by khushal1988, Nov 12, 2010.

  1. khushal1988

    Thread Starter Member

    Nov 12, 2010
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    I have made parametric speaker which is a stereo system only work on 3.5mm stereo jack but i want to make a circuit for that in which i can talk through mic to send my voice as it is sending the stereo voice please help me out designing the mic circuit.
     
    Last edited: Nov 12, 2010
  2. Audioguru

    New Member

    Dec 20, 2007
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    A microphone has an output level of only 5mV AC so it needs a pre-amplifier.
    If the microphone and the amplified speakers are near each other so that the microphone hars the speakers then you will have feedback howling.
     
  3. khushal1988

    Thread Starter Member

    Nov 12, 2010
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    can u please tell me which circuit is correct for it among the two. and if there are any errors please correct them
    circuits are attached.
     
  4. khushal1988

    Thread Starter Member

    Nov 12, 2010
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    1k & 470 is the resistors
    4.7mf is capacitor
    Jack plug Male Stereo
    Battery holder 2 AA
    these are for mic1
    c1=1000mf
    c2=100mf
    r2=r1/10=220ohm
    9v battery
    these are for mic 2
     
  5. Audioguru

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    Dec 20, 2007
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    Your left circuit shows two electret microphones and no preamplifiers for them. Do you have two heads? Usually only a single microphone is used for one person.

    Your right circuit is a transistor microphone preamplifier showing a single electret microphone. The transistor will produce high distortion.
     
  6. khushal1988

    Thread Starter Member

    Nov 12, 2010
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    can u please provide me with the exact circuit to use , please send me a circuit which is in working condition and which works for my stereo system.
     
  7. khushal1988

    Thread Starter Member

    Nov 12, 2010
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    i need circuit diagram along with some explanation , so i could complete my project soon as possible , i am newbie please help me out sir
    Audio Guru Please help me u got my point please make a circuit diagram for me.
     
  8. Audioguru

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    Dec 20, 2007
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    Your circuits do not have a 470 ohm resistor and do not have a C2.
    Make two of the transistor preamplifier circuits.

    But a microphone is mono, not stereo so why do you have two microphones?
    How will you prevent feedback howling?
     
  9. khushal1988

    Thread Starter Member

    Nov 12, 2010
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    let me explain again i have a circuit designed which works on a stereo jack , i connect it with computer and listen the voice of the voice played in computer through speaker now my problem is to talk in a mic which can transmit my voice in the speaker but using the stereo 3.5mm jack so how can i do it can u please draw me the circuit diagram for that shall be very thankful to you sir waiting for the reply. and if we can contact through email please leave me ur email i want to discuss it with you. if possible otherwise tell me here.
     
  10. khushal1988

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    Nov 12, 2010
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    i want my voice to be played in the system and people can hear my voice when i talk in mic instead of connecting it to the computer. but the mic should be on stereo
     
  11. iONic

    AAC Fanatic!

    Nov 16, 2007
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  12. khushal1988

    Thread Starter Member

    Nov 12, 2010
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    do this circuit works for a stereo input ? as the system designed can get an input a stereo only .
     
  13. Audioguru

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    A microphone is mono, not stereo. The output of a single preamplifier can feed both inputs of a stereo amplifier then both speakers will have the same signal.
     
  14. khushal1988

    Thread Starter Member

    Nov 12, 2010
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    i am not understanding sir , i have a stereo system designed which works with computer speaker jack 3.5mm stereo jack and mp3 players but i want to design a mic system for that stereo system in which i want to deliver my own voice in talking through the mic.
     
  15. khushal1988

    Thread Starter Member

    Nov 12, 2010
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    please send me the circuit diagram for that or modify my diagrams sent before as an attachment and send them to me again. but after the modification.
     
  16. Audioguru

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    I assume that you have a stereo amplifier, not just a 3.5mm stereo jack. Stereo amplifiers have many different kinds of input jacks.
    You have only a single head and a single mouth so use just a single microphone and a single preamplifier for it. The output of the preamplifier can feed both inputs of your stereo amplifier.

    Make any preamplifier circuit that you want. An audio opamp will make a much better mic preamp than a transistor circuit.
     
  17. khushal1988

    Thread Starter Member

    Nov 12, 2010
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    please check this one will this be ok, see the attachements component list :

    R1 4.7 kohm
    R2 220 kohm
    R3 2.2 kohm
    R4 120 ohm
    C1..C4 10 uF 16V electrolytic
    C5 100 uF 16V electrolytic
    D1 Red LED
    Q1 BC547B
    SW1 on/off switch
     
  18. Audioguru

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    Now you show a very simple old transistor mic preamp circuit.
    But it has an input for an electret mic and another input for a dynamic mic. You must decide which type of mic you will use.
     
  19. khushal1988

    Thread Starter Member

    Nov 12, 2010
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    which one is better for the system electret or dynamic ?
     
  20. Audioguru

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    An electret mic is small, has excellent sound quality, is used in many audio products and is inexpensive. Some dynamic microphones have poor sound quality and are expensive.
     
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