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    This audio noise filter circuit is a bandpass filter for audio frequency band. It filters unwanted signals that are lower or higher than the audio frequencies.
    It has 2 filters: a low pass filter and a high pass filter in a cascade configuration.
    Both filters are second-order filters with a 24 dB/octave fiter capability. The 3 dB cut-off freq. are 11.8 Hz and 10.7 kHz.

    The bandpass characteristic can be changed by changing the values of the capacitors and resistors. If you want to raise the bottom cut-off freq., you must reduce the values of C1 up to C4. For lowering the bottom cut-off freq. you must increase the values.

    If you want to reduce the top cut-off f you must raise the values of R5 up to R8 and decrease it in order to increase the top cut-off frequency.

    Noise Filter circuit diagram

    noise filter diagram

    Audio Noise Filter Parts List

    R1 = R2 = 56kΩ
    R3 = 39kΩ
    R4 = 100kΩ
    R5 = R6 = R7 = R8 = 3.3kΩ
    C1 = C2 = C3 = C4 = 0.33µF ceramic
    C5 = C6 = 0.0033µF ceramic
    C7 = 0.0047µF ceramic
    C8 = 0.0018µF ceramic
    IC1 = IC2 = NE5532N

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    7 Responses to "Audio Noise Filter Circuit"

    1. FENIX FROM DESERT says: on June 23, 2012 at 7:28 am

      Não entendi nada.
      Poderiam me explicar algo mais simples por exemplo um filtro com elementos passivos.

    2. i want digital filter

    3. i want to add digital filter in this circuit

    4. i want full report of the audio noise filter circuit please send to my mail ID…


    6. If you want use this filter in a DC voltage application and improve the IC ‘s used in the schematic use IC part number OPA2107G4 from Texas Instruments . Also use part# 987-1173-ND from DigiKey it is a trimmer resistor to replace R5-R8 in the schematic . If you do this improvement it will give you a better filter with even less noise and give you an adjustable upper cut off frequency. The trimmer is adjustable from 2 ohm – 2 Mohm.

    7. Sir I make amplifier using STK 4141 ic but didn’t got nice response from that can you send the best filter for bass as well as trable and some digital technology

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