Audio Noise Filter and Bandpass Filter for Audio Frequency Band
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.
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| Audio Noise Filter and Bandpass Filter for Audio Frequency Band |
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
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
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
