Low pass filter for subwoofer

Description.
Many low pass filter circuits for subwoofer are given here and this is just another one. The circuit given here is based on the opamp TL062 from ST Micro electronics. TL062 is a dual high input impedance J-FET opamp which has very low power consumption and high slew rate. The opamp has excellent audio characteristics and is very suitable for this circuit.
Out of the two opamps inside TLC062, first one is wired as the mixer cum pre amplifier stage. The left and right channel are connected to the inverting input of IC1a for mixing. The gain of first stage can be adjusted using POT R3.The output of the first stage is connected to the input of second stage through the filter network comprising of components R5,R6,R7,R8,C4 and C5. The second opamp (IC1b) serves as a buffer and the filtered output is available at the pin 7 of the TLC062.

Circuit diagram.

Power supply for the circuit.

Notes.

  • Assemble the circuit on a good quality PCB.
  • The circuit can be powered from a +12/-12 V DC dual power supply.
  • IC1 must be mounted on a holder.

Show Comments

69 thoughts on “Low pass filter for subwoofer

  1. Midhunmp

    Sir,
    I am new in electronic field. I want to build a subwoofer amp. I made a 150w poweramp for subwoofer using +35/-35v 5amp dual power supplay. Now i have a doubt. If any problem can i connect the filter circut to the 35v 5amp dual power supplay? Please clear my doubt sir. And give me a solution to overcome this limitation. Iam hoping ur replay. Please help me… Have a good day..

    Reply
  2. vicky

    hello sir i wan’a surrounding circuit that means left right that to centre(mid range) and surround left right circuit

    Reply
  3. cooool

    sir I built both 100 watt subwoofer amplifier and subwoofer filter but nothing works. I built subwoofer filter using 47k fixed resistor instead of pot and I connected to a sterio amplifier (I don’t know power of amplifier) but nothing come out please help in building both circuits I spend nearly Rs. 2000/- for this circuit’s component. thankyou.

    Reply
  4. GS TURNA

    Hello sir, this circuit oprate on 12-12 G.But i need it work on 12 0. Is this possble, if yes then how please help me

    Reply
  5. shreyas98

    can some one please tell me the function of R6 and R7 and if i could use 2 presets and furthermore can i use a preset for R3 to make rare adjustments?

    Reply
    • Seetharaman

      Hi for R3 you can use a preset as it is meant level, if you are going to use only the same input source always. R6 & R7 should be a ganged pot or you can use 2 identical presets adjust them in similar fasion such that they operate like a ganged control. you can attach both the presets with a thin non conductive shaft.

      Reply
  6. cooool

    Sir can I connect this filter output to a 50watt power amplifire or there is any specific amplifire for this circuit please reply me.

    Reply
  7. rujtam

    Sir,maybe you have a layout pcb this filter,please send to my mail,,actualy I confuse conect pins pot line..
    Thanks very much….

    Reply
  8. rujtam

    Sir,,I tes this filter,I connect out to subwoofer,but I can hear a sound,what the problem,or I must conect that to power amplifier..
    Thanks sir,,I am newbie…:)

    Reply
    • Seetharaman

      you have to connect the output of this filter to a subwoofer power amplifier of not less than 40watts RMS

      Reply
  9. jay olvido

    sir im an enthusiast bout electronics .favor please sir please do mail me tthe more detail schematic of this low pass filter sir? with the values of each capacitors and resistors used? it means a lot to me sir if you grant my asked favor.thank you in advance

    Reply
  10. Pankaj

    Hello Sir,
    I am planning to build this circuit but I am not able to find this tl062 ic. so can I use tl074 instead of tl062.

    Reply
    • Seetharaman

      YTou can use TL072 or TL082 they are dual Fet opamps. TL074 is quad you can use them also. Two of the quad can be used

      Reply
  11. Zygis

    Hi, i made this filter and it works perfect! I’m really happy with that. But i had to change R1 and R2 in to lower nominal couse it plays very quietly. I change to 4.7kOhm and than everything worked fine. Thank you! :)

    P.S I was using my cell phone to test this filter.

    Reply
  12. jenken

    thank u sir? i’ve done it the sound very low? ur the best?more power to u! im using ic op amp.4558?

    Reply
  13. Pankaj

    sir also how can I fabricate it on a copper clad board?????
    I mean from where I can get its board layout

    Reply
    • Seetharaman

      Hi Pankaj IC1a is used as a gain controlled buffer amplifier. IC1b is used as an active tunable low pass filter in the very low audio frequency area(with R6 & R7 filter charesterestic can changed a little.
      You can use an universal board (staight line vero boards or connecting perforated dotted boards suitably)

      Reply
  14. SUNRISEZERO

    Dear sir,
    I would like to ask you if this filter can be used to infrasound frequencies … 1 to 12 Hz
    thank you

    Reply
  15. wally francia

    two input signal left and right will be feed to this amp. and the output will become one??

    Reply
  16. walter

    sir is my understanding is correct that i will feed left and right signal in the input of the circuit, and later it will become one output…

    Reply
  17. walter

    do you have simple transistorized low pass filter? kindly send me if you have one because IC is kinda expensive thanks…

    Reply
  18. Seetharaman

    Hi Alam through an 100K volume control you can feed the output of this filter to any high power amplifier.
    Hi Abhinash you have to connect the output through high power amplifier to the speaker (sub woofer)

    Reply
  19. alam

    how to use this circuit with 150 watt amplifier ???
    1) by connecting its output to the inputs of amplifier
    or if it should be connected by other method so please define it …

    Reply
  20. Abinash

    Sir, shall i connect the output of above circuit directly to speaker or i have to connect a TDA7240A amplifier to it???
    Thanx in advance???

    Reply
  21. arunkumar

    i assembled 100 Watt sub woofer amplifier. but it somke
    please do needful

    used spare
    ==========

    24-0-24 transformer 5 ams

    thank you

    k.arunkumar

    Reply
  22. arunkumar

    i assembled 100 Watt sub woofer amplifier. but it somke
    please do needful

    used spare
    ==========

    24-0-24 fransformer 5 ams

    thank you

    k.arunkumar

    Reply
  23. prasad

    common man, need help !!! I saw this Circuit on the web which i
    was searching for kind of one
    for a long time and unfortunetly there
    are some mismatch between PCB,
    Data Sheet, Built PHOTO posted. i really
    need this circuit so, looking for help from you to understand the
    Circuit and need its working
    DIagram http://www.free-circuit.com/
    subwoofer-filter-gainer-auto-power-
    system-circuit/

    Reply
  24. vivek

    Thanks Seetharaman, for that website. I am working on this circuit and planning to connect it to a TDA 2030 audio amplifier im having will it work or do i need any other amplifier? Thanks in advance.

    Reply
  25. vivek

    thanks seetharaman for the reply and can you help me in getting dual power supply from single output transformer.
    thanks in advance

    Reply
  26. seetharaman

    Hi Vivek you can limit the upper frequency response from 30Hz to 150 Hz by the turn of the ganged potentiometer (stereo potentiometer).

    Reply
  27. seetharaman

    Hi Mujtaba these ICs are with bipolar inputs hence input impedance will be low and may load the filter circuit. It is recommended to use FET input operation amplifiers for these filter circuits.

    Reply
  28. Seetharaman

    Hi Mike NE5532 can be used as it works down to 6 volts(+3 & -3 volts).
    Hi Romesh it is between 60 and 160 Hz as per pot setting.

    Reply
  29. Romesh

    Hi, nice post. By the way what’s the cut off frequency? Or can we change it using the 22k pot. Thanks in advance.

    Reply
  30. Seetharaman

    Hi Rupjyoti you can use TL072 or TL082
    TL062 confirms to Military specification can work down to 4volt ( +2 & -2)
    TL072 confirms to Industrial specification can work down to 7volt ( +3.5 & -3.5)
    TL082 confirms to General Purpose use can work down to 12volt ( +6 & -6)hence for our use this is quite satisfactory

    Reply

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